RESUMO
BACKGROUND: Prader-Willi syndrome (PWS) is a rare multisystemic hereditary illness. Recombinant human growth hormone (rhGH) therapy is widely recognized as the primary treatment for PWS. This study aimed to examine how different PWS genotypes influence the outcome of rhGH treatment in children with PWS. METHODS: A review was conducted on 146 Chinese children with PWS, genetically classified and monitored from 2017 to 2022. Unaltered and modified generalized estimating equations (GEE) were employed to examine the long-term patterns in primary outcomes (growth metrics) and secondary outcomes (glucose metabolism metrics and insulin-like growth factor-1 (IGF-1)) during rhGH therapy. The study also evaluated the prevalence of hypothyroidism, hip dysplasia, and scoliosis before and after rhGH treatment. RESULTS: Children with PWS experienced an increase in height/length standard deviation scores (SDS) following rhGH administration. The impact of rhGH therapy on growth measurements was similar in both the deletion and maternal uniparental diploidy (mUPD) cohorts. Nevertheless, the deletion group was more prone to insulin resistance (IR) compared to the mUPD group. No significant variations in growth metrics were noted between the two groups (P > 0.05). At year 2.25, the mUPD group showed a reduction in fasting insulin (FINS) levels of 2.14 uIU/ml (95% CI, -4.26, -0.02; P = 0.048) and a decrease in homeostasis model assessment of insulin resistance (HOMA-IR) of 0.85 (95% CI, -1.52, -0.17; P = 0.014) compared to the deletion group. Furthermore, there was a decrease in the IGF standard deviation scores (SDS) by 2.84 (95% CI, -4.84, -0.84; P = 0.005) in the mUPD group during the second year. The frequency of hip dysplasia was higher in the mUPD group compared to the deletion group (P < 0.05). CONCLUSIONS: rhGH treatment effectively increased height/length SDS in children with PWS, with similar effects observed in both deletion and mUPD genotypes. Children with mUPD genetype receiving rhGH treatment may experience enhanced therapeutic effects in managing PWS.
Assuntos
Genótipo , Hormônio do Crescimento Humano , Síndrome de Prader-Willi , Humanos , Síndrome de Prader-Willi/tratamento farmacológico , Síndrome de Prader-Willi/genética , Hormônio do Crescimento Humano/uso terapêutico , Criança , Feminino , Masculino , Pré-Escolar , Fator de Crescimento Insulin-Like I , Adolescente , Resultado do Tratamento , Proteínas Recombinantes/uso terapêutico , Lactente , Hipotireoidismo/tratamento farmacológico , Hipotireoidismo/genética , Resistência à InsulinaRESUMO
Recombinant human growth hormone therapy (rhGH) has been widely accepted as the safe treatment for short stature in children with such genetic syndromes as Prader-Willi syndrome and Turner or Noonan syndrome. Some patients with short stature and rare genetic syndromes are treated with rhGH as growth hormone-deficient individuals or as children born small for their gestational age. After years of experience with this therapy in syndromic short stature, it has been proved that there are some aspects of long-term rhGH treatment beyond growth promotion, which can justify rhGH use in these individuals. This paper summarizes the data of a literature review of the effects of rhGH treatment beyond growth promotion in selected genetic syndromes. We chose three of the most common syndromes, Prader-Willi, Turner, and Noonan, in which rhGH treatment is indicated, and three rarer syndromes, Silver-Russel, Kabuki, and Duchenne muscular dystrophy, in which rhGH treatment is not widely indicated. Many studies have shown a significant impact of rhGH therapy on body composition, resting energy expenditure, insulin sensitivity, muscle tonus, motor function, and mental and behavioral development. Growth promotion is undoubtedly the primary benefit of rhGH therapy; nevertheless, especially with genetic syndromes, the additional effects should also be considered as important indications for this treatment.
Assuntos
Hormônio do Crescimento Humano , Síndrome de Prader-Willi , Humanos , Hormônio do Crescimento Humano/uso terapêutico , Síndrome de Prader-Willi/tratamento farmacológico , Síndrome de Prader-Willi/genética , Síndrome de Noonan/genética , Síndrome de Noonan/tratamento farmacológico , Síndrome de Turner/tratamento farmacológico , Síndrome de Turner/genética , Transtornos do Crescimento/tratamento farmacológico , Transtornos do Crescimento/genética , Proteínas Recombinantes/uso terapêuticoRESUMO
Genomic imprinting involves differential DNA methylation and gene expression between homologous paternal and maternal loci. It remains unclear, however, whether DNA replication also shows parent-of-origin-specific patterns at imprinted or other genomic regions. Here, we investigate genome-wide asynchronous DNA replication utilizing uniparental human embryonic stem cells containing either maternal-only (parthenogenetic) or paternal-only (androgenetic) DNA. Four clusters of imprinted genes exhibited differential replication timing based on parent of origin, while the remainder of the genome, 99.82%, showed no significant replication asynchrony between parental origins. Active alleles in imprinted gene clusters replicated earlier than their inactive counterparts. At the Prader-Willi syndrome locus, replication asynchrony spanned virtually the entirety of S phase. Replication asynchrony was carried through differentiation to neuronal precursor cells in a manner consistent with gene expression. This study establishes asynchronous DNA replication as a hallmark of large imprinted gene clusters.
Assuntos
Período de Replicação do DNA , Impressão Genômica , Humanos , Metilação de DNA/genética , Diferenciação Celular/genética , Replicação do DNA/genética , Células-Tronco Embrionárias Humanas/metabolismo , Família Multigênica , Síndrome de Prader-Willi/genética , AlelosRESUMO
BACKGROUND: Prader-Willi syndrome (PWS, MIM 176,270) and Angelman syndrome (AS, MIM 105,830) are caused by imprinting defects of chromosome 15q11-13, with loss of maternal gene expression causing AS and paternal gene expression causing PWS. The diagnosis, once established in most cases by using a methylation-specific PCR test, enables appropriate therapeutic interventions and avoids the need for further investigations. Genetic testing for PWS/AS is limited in Sri Lanka (and in other low- and middle-income countries), mainly because parents are unable to pay for testing as these are not funded by the health service. METHODS: Ninety cases (46 female) with clinical features suggesting PWS (n = 37) and AS (n = 53), referred by a pediatric endocrinologist and a pediatric neurologist, were recruited. Clinical information and blood samples were obtained following informed consent. DNA was extracted and methylation-specific PCR (MS-PCR) was performed following bisulfite modification of DNA by using an in-house method and a kit. Results were validated using known positive controls. Parent-child trio DNA samples were used in cases with confirmed PWS and AS to determine if the disease was due to a deletion or uniparental disomy. The cost of the MS-PCR testing of the two modification methods and the microsatellite analysis was determined. RESULTS: Among the suspected PWS cases, 19/37 were positive, while 5/53 of the suspected AS cases were positive. The lower identification rate of AS is probably related to the overlap of clinical features of this condition with other disorders. The kit-based modification method was more reliable, less time-consuming, and cost-effective in our laboratory. CONCLUSIONS: The kit-based modification followed by MS-PCR described in this study enables more affordable genetic testing of suspected PWS/AS cases, and this is likely to improve patient care by targeting appropriate therapy for the affected cases. Parental genetic counselling is made possible regarding the low recurrence risk, especially where a deletion or uniparental disomy is confirmed. In MS-PCR, negative cases with a strong clinical suspicion of AS, UBE3A mutation testing is required. In addition, imprinting center mutation/deletion testing may also be needed in strongly clinically suspected, MS-PCR negative PWS and AS cases.
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Síndrome de Angelman , Metilação de DNA , Testes Genéticos , Síndrome de Prader-Willi , Humanos , Síndrome de Prader-Willi/genética , Síndrome de Prader-Willi/diagnóstico , Síndrome de Angelman/genética , Síndrome de Angelman/diagnóstico , Sri Lanka , Testes Genéticos/métodos , Testes Genéticos/economia , Feminino , Masculino , Criança , Pré-Escolar , Reação em Cadeia da Polimerase/métodos , Adolescente , Lactente , Reprodutibilidade dos TestesRESUMO
Human cell line models, including the neuronal precursor line LUHMES, are important for investigating developmental transcriptional dynamics within imprinted regions, particularly the 15q11-q13 Angelman (AS) and Prader-Willi (PWS) syndrome locus. AS results from loss of maternal UBE3A in neurons, where the paternal allele is silenced by a convergent antisense transcript UBE3A-ATS, a lncRNA that terminates at PWAR1 in non-neurons. qRT-PCR analysis confirmed the exclusive and progressive increase in UBE3A-ATS in differentiating LUHMES neurons, validating their use for studying UBE3A silencing. Genome-wide transcriptome analyses revealed changes to 11 834 genes during neuronal differentiation, including the upregulation of most genes within the 15q11-q13 locus. To identify dynamic changes in chromatin loops linked to transcriptional activity, we performed a HiChIP validated by 4C, which identified two neuron-specific CTCF loops between MAGEL2-SNRPN and PWAR1-UBE3A. To determine if allele-specific differentially methylated regions (DMR) may be associated with CTCF loop anchors, whole genome long-read nanopore sequencing was performed. We identified a paternally hypomethylated DMR near the SNRPN upstream loop anchor exclusive to neurons and a paternally hypermethylated DMR near the PWAR1 CTCF anchor exclusive to undifferentiated cells, consistent with increases in neuronal transcription. Additionally, DMRs near CTCF loop anchors were observed in both cell types, indicative of allele-specific differences in chromatin loops regulating imprinted transcription. These results provide an integrated view of the 15q11-q13 epigenetic landscape during LUHMES neuronal differentiation, underscoring the complex interplay of transcription, chromatin looping, and DNA methylation. They also provide insights for future therapeutic approaches for AS and PWS.
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Fator de Ligação a CCCTC , Diferenciação Celular , Cromossomos Humanos Par 15 , Metilação de DNA , Impressão Genômica , Neurônios , Transcriptoma , Ubiquitina-Proteína Ligases , Humanos , Impressão Genômica/genética , Fator de Ligação a CCCTC/metabolismo , Fator de Ligação a CCCTC/genética , Cromossomos Humanos Par 15/genética , Neurônios/metabolismo , Metilação de DNA/genética , Transcriptoma/genética , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Diferenciação Celular/genética , Síndrome de Angelman/genética , Síndrome de Angelman/patologia , RNA Longo não Codificante/genética , Síndrome de Prader-Willi/genética , Síndrome de Prader-Willi/patologia , Síndrome de Prader-Willi/metabolismo , Proteínas Centrais de snRNP/genética , Proteínas Centrais de snRNP/metabolismo , Alelos , Linhagem Celular , EpigenomaRESUMO
PURPOSE: An investigation for the co-occurrence of two unrelated genetic disorders of muscular dystrophy and Prader-Willi syndrome (PWS) (OMIM#176270) using joint whole genome sequencing (WGS). METHODS: Trio WGS joint analysis was performed to investigate the genetic etiology in a proband with PWS, prolonged muscular hypotonia associated hyperCKemia, and early-onset obesity. The parents were unaffected. RESULTS: Results showed maternal isodisomy uniparental disomy (UPD) in chromosome 15, expanding from 15q11.2 to 15q22.2, including PWS regions at 15q11.2-15q13. Maternal heterodisomy was detected from 15q22.2 to 15q26.3. A pathogenic variant, NM_000070.3(CAPN3):c.550del (p.Thr184fs), was identified at 15q15.1 in a heterozygous state in the mother that was homozygous in the proband due to maternal isodisomy. CONCLUSION: This is the first study of the concurrent molecular etiology of PWS and calpainopathy (OMIM#253600) in the same patient. This report highlights the utility of joint analysis and the need for the assessment of autosomal recessive disease in regions of isodisomy in patients with complex and unexplained phenotypes.
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Calpaína , Cromossomos Humanos Par 15 , Síndrome de Prader-Willi , Dissomia Uniparental , Feminino , Humanos , Masculino , Calpaína/genética , Cromossomos Humanos Par 15/genética , Proteínas Musculares , Síndrome de Prader-Willi/genética , Síndrome de Prader-Willi/diagnóstico , Síndrome de Prader-Willi/patologia , Dissomia Uniparental/genética , Sequenciamento Completo do GenomaRESUMO
Prader-Willi syndrome (PWS) is a complex genetic neurodevelopmental disorder with multisystem impact and a unique behavior profile that evolves over the life span. Beyond the primary care needs of all children and adults, the unique medical concerns and management needs of those with PWS are best served in a multidisciplinary academic center. Our PWS center has provided care for individuals with PWS and their families since 1981. Our growth hormone studies contributed to growth hormone supplementation becoming standard of care in this country. Here, in collaboration with the primary care provider, early childhood intervention programs, schools and local parent organizations, solid, patient-centered care for affected individuals and their families can be provided across the life-span. The purpose of this article is to provide a brief overview of PWS and the attendant medical and behavior management challenges attendant to the disorder.
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Síndrome de Prader-Willi , Síndrome de Prader-Willi/terapia , Síndrome de Prader-Willi/diagnóstico , Síndrome de Prader-Willi/genética , Humanos , Criança , Hormônio do Crescimento Humano/uso terapêuticoRESUMO
BACKGROUND: Prader-Willi syndrome (PWS) is a genetic disorder characterized by abnormalities in the 15q11-q13 region. Understanding the correlation between genotype and phenotype in PWS is crucial for improved genetic counseling and prognosis. In this study, we aimed to investigate the correlation between genotype and phenotype in 45 PWS patients who previously underwent methylation-sensitive high-resolution melting (MS-HRM) for diagnosis. RESULTS: We employed methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) and Sanger sequencing, along with collecting phenotypic data from the patients for comparison. Among the 45 patients, 29 (64%) exhibited a deletion of 15q11-q13, while the remaining 16 (36%) had uniparental disomy. No statistically significant differences were found in the main signs and symptoms of PWS. However, three clinical features showed significant differences between the groups. Deletion patients had a higher prevalence of myopia than those with uniparental disomy, as well as obstructive sleep apnea and an unusual skill with puzzles. CONCLUSIONS: The diagnostic tests (MS-HRM, MS-MLPA, and Sanger sequencing) yielded positive results, supporting their applicability in PWS diagnosis. The study's findings indicate a general similarity in the genotype-phenotype correlation across genetic subtypes of PWS.
Assuntos
Genótipo , Fenótipo , Síndrome de Prader-Willi , Humanos , Síndrome de Prader-Willi/genética , Feminino , Masculino , Brasil , Pré-Escolar , Criança , Adolescente , Adulto , Dissomia Uniparental/genética , Cromossomos Humanos Par 15/genética , Lactente , Adulto JovemRESUMO
The neurodevelopmental disorders Prader-Willi syndrome (PWS) and Schaaf-Yang syndrome (SYS) both arise from genomic alterations within human chromosome 15q11-q13. A deletion of the SNORD116 cluster, encoding small nucleolar RNAs, or frameshift mutations within MAGEL2 result in closely related phenotypes in individuals with PWS or SYS, respectively. By investigation of their subcellular localization, we observed that in contrast to a predominant cytoplasmic localization of wild-type (WT) MAGEL2, a truncated MAGEL2 mutant was evenly distributed between the cytoplasm and the nucleus. To elucidate regulatory pathways that may underlie both diseases, we identified protein interaction partners for WT or mutant MAGEL2, in particular the survival motor neuron protein (SMN), involved in spinal muscular atrophy, and the fragile-X-messenger ribonucleoprotein (FMRP), involved in autism spectrum disorders. The interactome of the non-coding RNA SNORD116 was also investigated by RNA-CoIP. We show that WT and truncated MAGEL2 were both involved in RNA metabolism, while regulation of transcription was mainly observed for WT MAGEL2. Hence, we investigated the influence of MAGEL2 mutations on the expression of genes from the PWS locus, including the SNORD116 cluster. Thereby, we provide evidence for MAGEL2 mutants decreasing the expression of SNORD116, SNORD115, and SNORD109A, as well as protein-coding genes MKRN3 and SNRPN, thus bridging the gap between PWS and SYS.
Assuntos
Peptídeos e Proteínas de Sinalização Intracelular , Proteínas Intrinsicamente Desordenadas , Síndrome de Prader-Willi , Humanos , Cromossomos Humanos Par 15/genética , Citoplasma/metabolismo , Células HEK293 , Mutação , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Síndrome de Prader-Willi/genética , Proteínas/genética , Proteínas/metabolismo , RNA Nucleolar Pequeno/genéticaRESUMO
OBJECTIVES: Prader-Willi syndrome (PWS) is a rare and complex genetic disorder caused by the loss of expression of the paternal copy of the imprinted genes on chromosome 15q11-q13. A variety of findings have been reported on the phenotypic differences between the genetic subtypes of PWS. This article compares the clinical findings of 57 PWS patients by genetic subtype and explores possible associations in this context. METHODS: Methylationspecific multiplex ligation-dependent probe amplification and single nucleotide polymorphism microarrays were used to diagnose deletion and uniparental disomy (UPD). For phenotype-genotype correlation, clinical data were collected and genetic subgroups were compared statistically, and P â <â 0.05 was considered to indicate statistical significance. RESULTS: These 57 patients consisted of 15 type I deletions, 20 type II deletions, six atypic deletions, 11 heterodisomy UPD, four isodisomy UPD, and one translocation-type PWS. All patients had hypotonia, poor neonatal sucking, and feeding difficulties during infancy. Other PWS-related clinical findings, such as speech articulation problems (85.9%), sleep apnea (77.2%), normal birth length (71.9%), small hands/feet (71.9%), childhood polyphagia (57.9%), clinodactyly (56.1%), thick viscous saliva (54.4%), and behavioral problems (50.9%) were observed at varying rates with no statistical difference between genetic subtypes in general. CONCLUSION: This study highlights the phenotype-genotype associations on PWS from a cohort of Turkish pediatric patients as a single-center experience.
Assuntos
Estudos de Associação Genética , Fenótipo , Síndrome de Prader-Willi , Humanos , Síndrome de Prader-Willi/genética , Síndrome de Prader-Willi/diagnóstico , Masculino , Feminino , Pré-Escolar , Lactente , Turquia/epidemiologia , Criança , Genótipo , Dissomia Uniparental/genética , Adolescente , Cromossomos Humanos Par 15/genética , Polimorfismo de Nucleotídeo Único , Metilação de DNA , Recém-NascidoRESUMO
INTRODUCTION: Long-read whole genome sequencing like Oxford Nanopore Technology, is increasingly being introduced in clinical settings. With its ability to simultaneously call sequence variation and DNA modifications including 5-methylcytosine, nanopore is a promising technology to improve diagnostics of imprinting disorders. METHODS: Currently, no tools to analyze DNA methylation patterns at known clinically relevant imprinted regions are available. Here we present NanoImprint, which generates an easily interpretable report, based on long-read nanopore sequencing, to use for identifying clinical relevant abnormalities in methylation levels at 14 imprinted regions and diagnosis of common imprinting disorders. RESULTS AND CONCLUSION: NanoImprint outputs a summarizing table and visualization plots displays methylation frequency (%) and chromosomal positions for all regions, with phased data color-coded for the two alleles. We demonstrate the utility of NanoImprint using three imprinting disorder samples from patients with Beckwith-Wiedemann syndrome (BWS), Angelman syndrome (AS) and Prader-Willi syndrome (PWS). NanoImprint script is available from https://github.com/carolinehey/NanoImprint.
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Síndrome de Angelman , Síndrome de Beckwith-Wiedemann , Metilação de DNA , Sequenciamento por Nanoporos , Síndrome de Prader-Willi , Humanos , Síndrome de Angelman/genética , Síndrome de Angelman/diagnóstico , Síndrome de Beckwith-Wiedemann/genética , Síndrome de Beckwith-Wiedemann/diagnóstico , Sequenciamento por Nanoporos/métodos , Nanoporos , Síndrome de Prader-Willi/genética , Síndrome de Prader-Willi/diagnóstico , Análise de Sequência de DNA/métodosRESUMO
Prader-Willi syndrome (PWS) is the prototypic genomic disorder resulting from deficiency of paternally expressed genes in the human chromosome 15q11-q13 region. The unique molecular mechanism involving epigenetic modifications renders PWS as the most attractive candidate to explore a proof-of-concept of epigenetic therapy in humans. The premise is that epigenetic modulations could reactivate the repressed PWS candidate genes from the maternal chromosome and offer therapeutic benefit. Our prior study identifies an EHMT2/G9a inhibitor, UNC0642, that reactivates the expression of PWS genes via reduction of H3K9me2. However, low brain permeability and poor oral bioavailability of UNC0642 preclude its advancement into translational studies in humans. In this study, a newly developed inhibitor, MS152, modified from the structure of UNC0642, has better brain penetration and greater potency and selectivity against EHMT2/G9a. MS152 reactivated maternally silenced PWS genes in PWS patient fibroblasts and in brain and liver tissues of PWS mouse models. Importantly, the molecular efficacy of oral administration is comparable with the intraperitoneal route. MS152 treatment in newborns ameliorates the perinatal lethality and poor growth, maintaining reactivation in a PWS mouse model at postnatal 90 days. Our findings provide strong support for MS152 as a first-in-class inhibitor to advance the epigenetic therapy of PWS in humans.
Assuntos
Modelos Animais de Doenças , Epigênese Genética , Síndrome de Prader-Willi , Humanos , Animais , Síndrome de Prader-Willi/tratamento farmacológico , Síndrome de Prader-Willi/genética , Camundongos , Epigênese Genética/efeitos dos fármacos , Administração Oral , Antígenos de Histocompatibilidade/genética , Antígenos de Histocompatibilidade/metabolismo , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Histona-Lisina N-MetiltransferaseRESUMO
Prader-Willi syndrome (PWS) is a complex genetic disorder caused by three different types of molecular genetic abnormalities. The most common defect is a deletion on the paternal 15q11-q13 chromosome, which is seen in about 60% of individuals. The next most common abnormality is maternal disomy 15, found in around 35% of cases, and a defect in the imprinting center that controls the activity of certain genes on chromosome 15, seen in 1-3% of cases. Individuals with PWS typically experience issues with the hypothalamic-pituitary axis, leading to excessive hunger (hyperphagia), severe obesity, various endocrine disorders, and intellectual disability. Differences in physical and behavioral characteristics between patients with PWS due to deletion versus those with maternal disomy are discussed in literature. Patients with maternal disomy tend to have more frequent neurodevelopmental problems, such as autistic traits and behavioral issues, and generally have higher IQ levels compared to those with deletion of the critical PWS region. This has led us to review the pertinent literature to investigate the possibility of establishing connections between the genetic abnormalities and the endocrine disorders experienced by PWS patients, in order to develop more targeted diagnostic and treatment protocols. In this review, we will review the current state of clinical studies focusing on endocrine disorders in individuals with PWS patients, with a specific focus on the various genetic causes. We will look at topics such as neonatal anthropometry, thyroid issues, adrenal problems, hypogonadism, bone metabolism abnormalities, metabolic syndrome resulting from severe obesity caused by hyperphagia, deficiencies in the GH/IGF-1 axis, and the corresponding responses to treatment.
Assuntos
Estudos de Associação Genética , Síndrome de Prader-Willi , Síndrome de Prader-Willi/genética , Humanos , Doenças do Sistema Endócrino/genética , FenótipoRESUMO
Prader-Willi syndrome (PWS) is a complex epigenetic disorder caused by the deficiency of paternally expressed genes in chromosome 15q11-q13. This syndrome also includes endocrine dysfunction, leading to short stature, hypogonadism, and obscure hyperphagia. Although recent progress has been made toward understanding the genetic basis for PWS, the molecular mechanisms underlying its pathology in obesity remain unclear. In this study, we examined the adipocytic characteristics of two PWS-induced pluripotent stem cell (iPSC) lines: those with the 15q11-q13 gene deletion (iPWS cells) and those with 15q11-q13 abnormal methylation (M-iPWS cells). The transcript levels of the lipid-binding protein aP2 were decreased in iPWS and M-iPWS adipocytes. Flow-cytometry analysis showed that PWS adipocytes accumulated more lipid droplets than did normal individual adipocytes. Furthermore, glucose uptake upon insulin stimulation was attenuated compared to that in normal adipocytes. Overall, our results suggest a significantly increased lipid content and defective in glucose metabolism in PWS adipocytes.
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Adipócitos , Células-Tronco Pluripotentes Induzidas , Síndrome de Prader-Willi , Síndrome de Prader-Willi/patologia , Síndrome de Prader-Willi/metabolismo , Síndrome de Prader-Willi/genética , Adipócitos/metabolismo , Adipócitos/patologia , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes Induzidas/patologia , Glucose/metabolismo , Cromossomos Humanos Par 15/genética , Cromossomos Humanos Par 15/metabolismo , Proteínas de Ligação a Ácido Graxo/metabolismo , Proteínas de Ligação a Ácido Graxo/genética , Linhagem Celular , Metilação de DNA , Deleção de Genes , Metabolismo dos Lipídeos , Insulina/metabolismoRESUMO
Due to its rare nature and subtle dysmorphisms, Prader-Willi syndrome can be challenging to recognize and diagnose in the neonatal period. Feeding difficulties and hypotonia ('floppy infant') are the most striking characteristics. Prader-Willi syndrome requires specific follow-up and treatment, emphasizing the importance of early recognition.We encountered an infant of three months old with severe hypotonia. The hypotonia ameliorated spontaneously over time, although feeding per nasogastric tube was necessary. There were no apparent dysmorphisms. Extensive genetic investigations showed a maternal uniparental disomy of chromosome 15, fitting with Prader-Willi syndrome explaining all symptoms. After excluding contraindications, treatment with growth hormone therapy was started. Parents were educated regarding medical emergencies specific for Prader-Willi syndrome ('medical alerts'). Although Prader-Willi syndrome is rare, it should always be considered in cases of neonatal hypotonia. Early recognition is paramount as specific recommendations and treatment are warranted.
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Hipotonia Muscular , Síndrome de Prader-Willi , Humanos , Lactente , Diagnóstico Precoce , Hipotonia Muscular/etiologia , Hipotonia Muscular/diagnóstico , Síndrome de Prader-Willi/diagnóstico , Síndrome de Prader-Willi/genética , Dissomia UniparentalRESUMO
BACKGROUND: Diagnosing imprinting defects in neonates and young children presents challenges, often necessitating molecular analysis for a conclusive diagnosis. The isolation of genetic material from oral swabs becomes crucial, especially in settings where blood sample collection is impractical or for vulnerable populations like newborns, who possess limited blood volumes and are often too fragile for invasive procedures. Oral swab samples emerge as an excellent source of DNA, effectively overcoming obstacles associated with rare diseases. METHODS: In our study, we specifically addressed the determination of the quality and quantity of DNA extracted from oral swab samples using NaCl procedures. RESULTS: We compared these results with extractions performed using a commercial kit. Subsequently, the obtained material underwent MS-HRM analysis for loci associated with imprinting diseases such as Prader-Willi and Angelman syndromes. CONCLUSIONS: Our study emphasizes the significance of oral swab samples as a reliable source for obtaining DNA for MS-HRM analysis. NaCl extraction stands out as a practical and cost-effective method for genetic studies, contributing to a molecular diagnosis that proves particularly beneficial for patients facing delays in characterization, ultimately influencing their treatment.
Assuntos
Síndrome de Angelman , DNA , Impressão Genômica , Mucosa Bucal , Síndrome de Prader-Willi , Humanos , Mucosa Bucal/citologia , Mucosa Bucal/patologia , Síndrome de Angelman/genética , Síndrome de Angelman/diagnóstico , Síndrome de Prader-Willi/genética , Síndrome de Prader-Willi/diagnóstico , DNA/genética , DNA/isolamento & purificação , Cloreto de Sódio , Recém-Nascido , Masculino , Transtornos da Impressão GenômicaRESUMO
INTRODUCTION: A microdeletion including the SNORD116 gene (SNORD116 MD) has been shown to drive the Prader-Willi syndrome (PWS) features. PWS is a neurodevelopmental disorder clinically characterized by endocrine impairment, intellectual disability and psychiatric symptoms such as a lack of emotional regulation, impulsivity, and intense temper tantrums with outbursts. In addition, this syndrome is associated with a nutritional trajectory characterized by addiction-like behavior around food in adulthood. PWS is related to the genetic loss of expression of a minimal region that plays a potential role in epigenetic regulation. Nevertheless, the role of the SNORD116 MD in DNA methylation, as well as the impact of the oxytocin (OXT) on it, have never been investigated in human neurons. METHODS: We studied the methylation marks in induced pluripotent stem-derived dopaminergic neurons carrying a SNORD116 MD in comparison with those from an age-matched adult healthy control. We also performed identical neuron differentiation in the presence of OXT. We performed a genome-wide DNA methylation analysis from the iPSC-derived dopaminergic neurons by reduced-representation bisulfite sequencing. In addition, we performed RNA sequencing analysis in these iPSC-derived dopaminergic neurons differentiated with or without OXT. RESULTS: The analysis revealed that 153,826 cytosines were differentially methylated between SNORD116 MD neurons and control neurons. Among the differentially methylated genes, we determined a list of genes also differentially expressed. Enrichment analysis of this list encompassed the dopaminergic system with COMT and SLC6A3. COMT displayed hypermethylation and under-expression in SNORD116 MD, and SLC6A3 displayed hypomethylation and over-expression in SNORD116 MD. RT-qPCR confirmed significant over-expression of SLC6A3 in SNORD116 MD neurons. Moreover, the expression of this gene was significantly decreased in the case of OXT adjunction during the differentiation. CONCLUSION: SNORD116 MD dopaminergic neurons displayed differential methylation and expression in the COMT and SLC6A3 genes, which are related to dopaminergic clearance.
Assuntos
Comportamento Aditivo , Metilação de DNA , Neurônios Dopaminérgicos , Células-Tronco Pluripotentes Induzidas , Síndrome de Prader-Willi , RNA Nucleolar Pequeno , Metilação de DNA/genética , Humanos , Células-Tronco Pluripotentes Induzidas/metabolismo , Neurônios Dopaminérgicos/metabolismo , Síndrome de Prader-Willi/genética , Síndrome de Prader-Willi/metabolismo , RNA Nucleolar Pequeno/genética , RNA Nucleolar Pequeno/metabolismo , Comportamento Aditivo/genética , Comportamento Aditivo/metabolismo , Epigênese Genética/genética , Ocitocina/metabolismo , Adulto , Diferenciação Celular/genética , Masculino , Feminino , Proteínas da Membrana Plasmática de Transporte de Dopamina/genética , Proteínas da Membrana Plasmática de Transporte de Dopamina/metabolismoRESUMO
BACKGROUND: The 15q11-q13 region is a genetic locus with genes subject to genomic imprinting, significantly influencing neurodevelopment. Genomic imprinting is an epigenetic phenomenon that causes differential gene expression based on the parent of origin. In most diploid organisms, gene expression typically involves an equal contribution from both maternal and paternal alleles, shaping the phenotype. Nevertheless, in mammals, including humans, mice, and marsupials, the functional equivalence of parental alleles is not universally maintained. Notably, during male and female gametogenesis, parental alleles may undergo differential marking or imprinting, thereby modifying gene expression without altering the underlying DNA sequence. Neurodevelopmental disorders, such as Prader-Willi syndrome (PWS) (resulting from the absence of paternally expressed genes in this region), Angelman syndrome (AS) (associated with the absence of the maternally expressed UBE3A gene), and 15q11-q13 duplication syndrome (resulting from the two common forms of duplications-either an extra isodicentric 15 chromosome or an interstitial 15 duplication), are the outcomes of genetic variations in this imprinting region. METHODS: Conducted a genomic study to identify the frequency of pathogenic variants impacting the 15q11-q13 region in an ethnically homogenous population from Bangladesh. Screened all known disorders from the DECIPHER database and identified variant enrichment within this cohort. Using the Horizon analysis platform, performed enrichment analysis, requiring at least >60% overlap between a copy number variation and a disorder breakpoint. Deep clinical phenotyping was carried out through multiple examination sessions to evaluate a range of clinical symptoms. RESULTS: This study included eight individuals with clinically suspected PWS/AS, all previously confirmed through chromosomal microarray analysis, which revealed chromosomal breakpoints within the 15q11-q13 region. Among this cohort, six cases (75%) exhibited variable lengths of deletions, whereas two cases (25%) showed duplications. These included one type 2 duplication, one larger atypical duplication, one shorter type 2 deletion, one larger type 1 deletion, and four cases with atypical deletions. Furthermore, thorough clinical assessments led to the diagnosis of four PWS patients, two AS patients, and two individuals with 15q11-q13 duplication syndrome. CONCLUSION: Our deep phenotypic observations identified a spectrum of clinical features that overlap and are unique to PWS, AS, and Dup15q syndromes. Our findings establish genotype-phenotype correlation for patients impacted by variable structural variations within the 15q11-q13 region.
Assuntos
Síndrome de Angelman , Síndrome de Prader-Willi , Humanos , Feminino , Masculino , Animais , Camundongos , Variações do Número de Cópias de DNA/genética , Alelos , Síndrome de Angelman/genética , Síndrome de Prader-Willi/genética , Bangladesh , MamíferosRESUMO
OBJECTIVE: To estimate the prevalence of epilepsy and febrile seizures and their association with genotype, i.e., 15q11-q13 deletions, uniparental chromosome 15 disomy (UPD) and other mutations, in the population with Prader-Willi syndrome (PWS). METHODS: A systematic search of Medline, Scopus, Web of Science and the Cochrane Library was conducted. Studies estimating the prevalence of seizures, epilepsy and febrile seizures in the PWS population were included. Meta-analyses of the prevalence of epilepsy and febrile seizures and their association with genotype using the prevalence ratio (PR) were performed. RESULTS: Fifteen studies were included. The prevalence of epilepsy was 0.11 (0.07, 0.15), similar to the prevalence of febrile seizures, with a prevalence of 0.09 (0.05, 0.13). The comparison "deletion vs. UPD" had a PR of 2.03 (0.90, 4.57) and 3.76 (1.54, 9.18) for epilepsy and febrile seizures. CONCLUSIONS: The prevalence of seizure disorders in PWS is higher than in the general population. In addition, deletions in 15q11-q13 may be associated with a higher risk of seizure disorders. Therefore, active screening for seizure disorders in PWS should improve the lives of these people. In addition, genotype could be used to stratify risk, even for epilepsy, although more studies or larger sample sizes are needed.
Assuntos
Epilepsia , Síndrome de Prader-Willi , Humanos , Síndrome de Prader-Willi/genética , Síndrome de Prader-Willi/complicações , Síndrome de Prader-Willi/epidemiologia , Epilepsia/genética , Epilepsia/epidemiologia , Prevalência , Genótipo , Cromossomos Humanos Par 15/genéticaRESUMO
Feeding difficulties, aspiration, and failure to thrive in infancy are commonly seen in patients with Prader-Willi Syndrome (PWS) and attributed to hypotonia. Patients with PWS and laryngeal clefts were identified by review of medical records at three tertiary care children's hospitals between 2017 and 2022. We present three patients with PWS with feeding difficulties who were also found to have laryngeal clefts which likely contributed to their feeding difficulties. Additional factors such as airway anomalies should be considered in patients with PWS, especially when swallowing dysfunction, dysphagia, or abnormal swallow evaluations are present.