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Background: Boucher-Neuhäuser syndrome (BNS, MIM 215470) is a rare autosomal recessive syndrome caused by mutations in the PNPLA6 gene. Few BNS cases have been reported for functional validation at the RNA level. Herein, we report on the family of a 17-year-old girl with clinical characteristics of BNS, genetic validation, and a systematic review of PNPLA6 variants related to BNS. Methods: Clinical data and blood samples were collected from the patient and their parents, and whole-exome sequencing was performed and confirmed by Sanger sequencing. RNA-sequencing (RNA-Seq) and quantitative RT-PCR (qRT-PCR) were performed, and the three-dimensional protein structures of the variants were predicted. Results: We report a 17-year-old female with progressive night blindness since the age of four, primary amenorrhea, and non-development of secondary sexual characteristics. Her impaired vision was diagnosed as retinal pigmentary degeneration of the retina. She had congenital hypogonadotropic hypogonadism (CHH) but no cerebellar ataxia at present. Two novel compound heterozygous variants (c.2241del/p.Met748TrpfsTer65 and c.2986A>G/p.Thr996Ala) of the PNPLA6 gene (NM_006702.4) were identified by whole-exome sequencing. The former variant was carried from her healthy father and has not been reported previously. The latter was inherited from her healthy mother and was noted in a report without functional studies. The RT-PCR results showed that the mRNA expression of PNPLA6 was lower in this patient and her father than in the control group. She was diagnosed with BNS. Both variants (c.2241del and c.2986A>G) were likely pathogenic according to the ACMG criteria. The novel variants in the PNPLA6 gene related to Boucher-Neuhäuser syndrome were summarized in this article. Conclusion: The possibility of Boucher-Neuhäuser syndrome should be considered when patients present with night blindness, impaired vision, and hypogonadotropic hypogonadism. Gene sequencing is currently the primary diagnostic method. Herein, novel compound heterozygous variants of PNPLA6 were identified in a BNS patient, and its function was verified at the RNA level. The PNPLA6 c.2241del variant is novel and potentially pathogenic, expanding the mutation spectrum in PNPLA6.

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Gordon Holmes syndrome (GHS) is an autosomal recessive disease characterized by cerebellar ataxia and hypogonadotropic hypogonadism. Among the genes associated with this syndrome, mutations in PNPLA6 have been detected and correlated with the phenotype of GHS. We report a case of a patient affected with GHS, confirmed by physical, neurological, laboratory and genetic analyses. Two compound heterozygous missense mutations on the PNPLA6 gene described as probably damaging/damaging in multiple in silico predictive tools have been detected with massive multigene sequencing. Interestingly, brain MRI uncovered abnormalities in the periventricular white matter, which so far have not been associated with GHS caused by PNPLA6 mutations.

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Purpose: The current study aims to raise awareness of Boucher - Neuhauser syndrome (BNHS) that occurs as a rare phenotype due to biallelic pathogenic variants in the PNPLA6 gene.Methods: Detailed family histories and clinical data were recorded. Whole exome sequencing was performed and co-segregation analysis of the family was done by sanger sequencing. Also, review of 28 molecularly confirmed patients with BNHS from the literature was evaluated.Results: We identified a missense homozygous variant (c.3524 C > G (p.Ser1175Cys)) in the PNPLA6 gene, which explains the phenotype of the patient and neurologic, ophthalmologic, endocrine, and genetic evaluations established a diagnosis of BNHS. Symptoms, ethnicity, clinical and genetic findings of 28 molecularly confirmed patients with BNHS from the literature were also presented.Conclusion: We present the main findings of a Turkish family with BNHS together with detailed clinical and genetic profiles of patients diagnosed as BNHS that have been molecularly confirmed in the literature so far.

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PNPLA6-related disorders include several phenotypes, such as Boucher-Neuhäuser syndrome, Gordon Holmes syndrome, spastic paraplegia, photoreceptor degeneration, Oliver-McFarlane syndrome and Laurence-Moon syndrome. In this study, detailed clinical evaluations and genetic testing were performed in five (4 Chinese and 1 Caucasian/Chinese) syndromic retinal dystrophy patients. Genotype-phenotype correlations were analyzed based on review of the literatures of previously published PNPLA6-related cases. The mean age of patients and at first visit were 20.8 years (11, 12, 25, 28, 28) and 14.2 years (4, 7, 11, 24, 25), respectively. They all presented with severe chorioretinal dystrophy and profoundly decreased vision. The best corrected visual acuity (BCVA) ranged from 20/200 to 20/2000. Systemic manifestations included cerebellar ataxia, hypogonadotropic hypogonadism and hair anomalies. Six novel and three reported pathogenic variants in PNPLA6 (NM_001166111) were identified. The genotypes of the five cases are: c.3134C > T (p.Ser1045Leu) and c.3846+1G > A, c.3547C > T (p.Arg1183Trp) and c.1841+3A > G, c.3436G > A (p.Ala1146Thr) and c.2212-10A > G, c.3436G > A (p.Ala1146Thr) and c.2266C > T (p.Gln756*), c.1238_1239insC (p.Leu414Serfs*28) and c.3130A > G (p.Thr1044Ala). RT-PCR confirmed that the splicing variants indeed led to abnormal splicing. Missense variants p.Thr1044Ala, p.Ser1045Leu, p.Ala1146Thr, p.Arg1183Trp and c.3846+1G > A are located in Patatin-like phospholipase (Pat) domain. In conclusion, we report the phenotypes in five patients with PNPLA6 associated syndromic retinal dystrophy with variable systemic involvement and typical choroideremia-like fundus changes. Ocular manifestations may be the first and the only findings for years. All of our patients carried one severe deleterious variant (stop-gain or splicing variant) and one milder variant (missense variant). Retinal involvement was significantly correlated with severe deleterious variants and variants in Pat domain.

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BACKGROUND: Gordon Holmes syndrome (GHS), characterized by cerebellar ataxia and hypogonadotropic hypogonadism (HH), has been related to recessive mutations in PNPLA6 gene. AIMS OF THE STUDY: Describe one Portuguese family with GHS due to compound heterozygosity of two new PNPLA6 variants. METHODS: Report on the clinical presentation, diagnostic and genetic workup to reach GHS diagnosis. RESULTS: The index case presented with slight cognitive impairment and primary amenorrhea, developed at the age of 25 a cerebellar syndrome. Her neurological exam revealed ataxia and mild extrapyramidal syndrome. She was born from non-consanguineous parents and had 8 siblings. Two of her sisters also had history of primary amenorrhea, tremor and ataxia. All 3 were diagnosed with HH and previous FMR1 gene screening on her sisters revealed a 51 CGGs allele. However, 2 normal-sized FMR1 alleles were identified on the proband thus excluding the FXTAS diagnosis in the family. Further PNPLA6 variant screening revealed 2 novel variants in compound heterozygosity [c.2404G > C]; [c.4081C > T], which co-segregated with the disease. CONCLUSIONS: This case shows how incomplete studies can be misleading, increases genetic knowledge of GHS and expands its clinical spectrum. The coexistence of a FMR1 intermediate allele in this family constituted an additional challenge in the etiological investigation.

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Autosomal recessive cerebellar ataxias (ARCAs) represent a heterogeneous group of inherited disorders. The association of early-onset cerebellar ataxia with hypogonadotropic hypogonadism is related to two syndromes, known as Gordon Holmes syndrome (GHS-ataxia and pyramidal signs with hypogonadotropic hypogonadism) and Boucher-Neuhäuser syndrome (BNS-ataxia with chorioretinal dystrophy). Mutations in the PNPLA6 gene have been identified as the cause of hereditary spastic paraplegia and complex forms of ataxia associated with retinal and endocrine manifestations. We reported two Brazilian patients with sporadic, progressive cerebellar ataxia, associated with hypogonadotropic hypogonadism, in whom the GHS and BNS were confirmed by the demonstration of compound heterozygote mutations in the PNPLA6 gene. Genetic analysis of the patient 1 revealed compound heterozygous mutations, one allele in exon 34 and the other allele in exon 29. Genetic exam of the patient 2 also demonstrated compound heterozygous mutations. Three were novel mutations. The missense mutation c.3373G> A, found in the BNS patient, was previously related to Oliver-McFarlane syndrome. These different mutations in this gene suggest a complex phenotype associated disease spectrum.

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Objective To investigate the clinical manifestations, genetic basis and related literatures of Boucher-Neuh(a)user syndrome(BNS), hoping to help physicians recognize this rare disease. Methods A 25-year-old BNS patient was reported.The clinical manifestations and the laboratory data including fundus examination, blood testing, brain MRI and genetic data were summarized.The related literatures were also reviewed.Results The patient presented with tremors, ataxia, secondary sexual characteristics dysplasia,epilepsy, and then got worse progressively.Brain MRI showed severe cerebellar atrophy.Two mutations of PNPLA6 gene were found: one is the heterozygous mutation c.1811C >T (p.A604V),which has not been reported;another is c.2990C>T(p.S997L),which has been reported as a pathogenic mutation related to BNS.Conclusion PNPLA6-related BNS may be considered for adolescent patients with tremor and ataxia,secondary sexual characteristics dysplasia and epilepsy.