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BACKGROUND: Ectodermal dysplasias (EDs) are a heterogeneous group of genetic conditions affecting the development and/or homeostasis of two or more ectodermal derivatives, including hair, teeth, nails, and certain glands. There are currently 49 recognized EDs with molecularly confirmed etiology. The EDs are very rare disorders, individually and in aggregate. Very little is published regarding the prevalence of these rare disorders. As a result of the genomics revolution, rare diseases have emerged as a global health priority. The various disabilities arising from rare disorders, as well as diagnostic and treatment uncertainty, have been demonstrated to have detrimental effects on the health, psychosocial, and economic aspects of families affected by rare disorders. Contemporary research methodologies and databases can address what have been historic challenges encountered when conducting research on rare diseases. OBJECTIVE: In this study, we aim to ascertain period prevalence rates for several of the more common ectodermal dysplasia syndromes, by querying a large multicenter database of electronic health records, Oracle Real-World Data. METHODS: For each of the included ectodermal dysplasia syndromes a clinical definition was developed by a committee of international experts with interests in EDs. The clinical definitions were based upon a combination of clinical features and designated by ICD-9 and ICD-10 codes. The January 2023 version of the Oracle Real-World Data database was queried for medical records that coincided with the clinical definitions. For our study, there were 64,523,460 individual medical records queried. RESULTS: Period prevalence rates were calculated for the following ED disorders: hypohidrotic ectodermal dysplasia, found to be 2.99 per 100,000; ectodermal dysplasia and immunodeficiency 1, 0.23 per 100,000; Clouston syndrome, 0.15 per 100,000; ectrodactyly ectodermal dysplasia and cleft lip/palate syndrome, 0.61 per 100,000; ankyloblepharon-ectodermal defects-cleft lip/palate syndrome, 0.36 per 100,000; focal dermal hypoplasia, 0.10 per 100,000; and incontinentia pigmenti, 0.88 per 100,000. CONCLUSION: This study established estimated period prevalence rates for several of the ectodermal dysplasia syndromes, and it demonstrated the feasibility of utilizing large multicenter databases of electronic health records, such as Oracle Real World Data.

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CASE HISTORY: A 4-month-old male Shih Tzu dog (Case 1) and an 11-month-old female Devon Rex cat (Case 2) were referred to specialist veterinary hospitals for evaluation of right thoracic lameness and growth abnormality in the distal aspect of the forelimb. CLINICAL FINDINGS: Non-weight-bearing lameness and decreased range of motion were noted in the affected limbs of both cases. Case 1 had a plantigrade stance, and a cleft separation between the first and second digits extending upwards to the distal third of the antebrachium. There was no pain on palpation, and the affected limb was shorter than the contralateral. Radiographic examination revealed cleft separation between metacarpal bones I and II, and carpal bone fusion (I, II, III), and the distal radius ended freely and was attached to the first metacarpal bone.Case 2 had a small cleft medial to metacarpal III. The limb was consistently held in abduction and had marked carpal varus. The limb had never been used for weight bearing. Radiographic examination showed agenesis of metacarpal bone II and separation of metacarpals I and III. The radius and ulna were separated and the radial head did not articulate normally at the elbow, leading to marked elbow incongruity. DIAGNOSIS: Ectrodactyly in both cases. TREATMENT AND OUTCOME: Amputation of the radius followed by ulnocarpal arthrodesis were performed in both cases. Follow-up evaluations up to 1 year (Case 1) and 10 weeks (Case 2) after surgery indicated satisfactory arthrodesis fusion, owner satisfaction, and a good clinical outcome. CLINICAL RELEVANCE: Ectrodactyly is a rare congenital deformity of the forelimb with a heterogeneous character, requiring an individualised treatment plan. These are the first cases reported in the literature of ectrodactyly in small animals that were treated successfully with ulnocarpal arthrodesis. This case series therefore provides evidence in support of this treatment option for this heterogeneous congenital deformity.

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Split hand/foot malformation is a heterogeneous congenital disorder mainly presented with a median cleft of hands or/and feet. It can be associated with long bone aplasia, a syndrome also known as split hand/foot syndrome with long bone deficiency (SHFLD), which is a very rare condition. We report a very rare case of a male fetus with SHFLD syndrome combined with fibular aplasia, tibial campomelia, and oligosyndactyly (FATCO) syndrome. FATCO syndrome is also an extremely infrequent congenital limb defect by itself. Based on our review of the literature, there appears to be no other FATCO case reported in Greece.

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OBJECTIVE: To describe a rare congenital deformity of the phalanges and the surgical details and outcome in a dog with ectrodactyly combined with polydactyly. STUDY DESIGN: Single case report. ANIMAL: A 3.5-month-old male intact mixed breed dog with forelimb lameness and paw malformations. METHODS: Surgery was performed on a dog with a congenital limb deformity consisting of resection of the extra bone and soft tissue structure to prevent further subluxation of the remaining metacarpals. Stabilisation consisted of a cortical screw in compression and a K wire across the proximal metacarpals. RESULTS: Postoperative radiographs showed adequate implant positioning and good reduction of the proximal metacarpal row. At six weeks, the dog showed improvement in limb function and weight bearing. Major complications occurred at twelve weeks, and revision surgery with implant removal was required. At six months, the dog showed near normal range of motion and no lameness. CONCLUSIONS AND CLINICAL RELEVANCE: The decision to perform surgery on a dog with limb deformity resulted in an almost physiological gait, and the dog showed no abnormalities in daily life. This report adds to the literature on congenital limb deformities by describing the combination of ectrodactyly and polydactylism in a canine species, including the surgical approach and outcome. However, the optimal management of this heterogeneous condition is currently unclear.

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OBJECTIVE: To describe in detail the lacrimal drainage system anomalies and review of literature in patients with Goldenhar syndrome, Rubinstein-Taybi syndrome (RTS), and Ectodermal-Ectrodactyly-Clefting syndrome (EECS), their management and outcomes. METHODS: A retrospective chart review from January 2011-June 2023 of all cases presenting to the Dacryology clinic with Goldenhar syndrome, RTS, and EECS was obtained. Data collected included demographics, laterality, clinical presentations, proximal and distal lacrimal drainage anomalies, associated systemic features, management, and outcomes. RESULTS: Eight children with Goldenhar syndrome (n = 13), three with RTS (n = 5) and three with EECS (n = 5) presented with lacrimal drainage system involvement. Cases with Goldenhar syndrome showed male predominance (5/8), and the mean age at presentation was 14.75 months. Four cases had simple CNLDO, seven cases with complex CNLDO (4 - buried probe and 3 - atonic sacs) and a single neonate presented with bilateral dacryocele. Patients with RTS presented with mean age of 36.33 months with male predominance. Probing under endoscopic guidance explored the anatomy thoroughly and those with altered nasal anatomy increased the probability of complex CNLDO. Those with EECS (n = 5) presented with a greater involvement of proximal lacrimal drainage system compared with Goldenhar syndrome and RTS, including anomalies like punctal agenesis, incomplete punctal canalization (IPC), ectopic puncta, canalicular stenosis, and complex CNLDO. CONCLUSIONS: A step-wise approach to assessing the proximal and lacrimal drainage system in those affected with craniofacial malformations and addressing them can result in satisfactory outcomes for the majority of patients.

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Copy number variation in loss of 7q21 is a genetic disorder characterized by split hand/foot malformation, hearing loss, developmental delay, myoclonus, dystonia, joint laxity, and psychiatric disorders. Osteogenesis imperfecta caused by whole gene deletions of COL1A2 is a very rare condition. We report a Turkish girl with ectrodactyly, joint laxity, multiple bone fractures, blue sclera, early teeth decay, mild learning disability, and depression. A copy number variant in loss of 4.8 Mb at chromosome 7 (q21.2q21.3) included the 58 genes including DLX5, DLX6, DYNC1I1, SLC25A13, SGCE, and COL1A2 . They were identified by chromosomal microarray analysis. We compared the findings in our patients with those previously reported. This case report highlights the importance of using microarray to identify the genetic etiology in patients with ectrodactyly and osteogenesis imperfecta.

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The 17th century was a time of scientific discovery in Europe. Leading academic centers provided the general population with an opportunity to view anatomic dissections of human bodies. Rather than portray idealized versions of individuals, Dutch painters were committed to accurately representing their models. This was true for Johannes Vermeer. The 2023 exhibition of Vermeer's paintings at the Rijksmuseum in Amsterdam provided an unprecedented opportunity to observe 28 of his 37 existing paintings simultaneously in person. Here the authors suggest that in at least eight paintings a visibly pregnant woman is present. Vermeer's wife was pregnant or lactating most of the time during their 22-year marriage. Further, evidence of specific medical findings and congenital anomalies such as polydactyly, ectrodactyly, alopecia, kyphosis, and hyperthyroidism were observed in the paintings. These have not been previously reported in the medical or art history literature.

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Introduction: To our knowledge, there are few examples of intrafamilial variability involving two different TP63-linked morphopathies within a same family. Here, we describe a Mexican family in which the son had ectrodactyly, ectodermal dysplasia, and cleft lip/palate syndrome 3 (EEC3), and his father acro-dermato-ungual-lacrimal-tooth (ADULT) syndrome, both heterozygous for the p.Arg266Gln pathogenic variant in TP63. Additionally, we reviewed the clinical information reported for this TP63 genotype. Case Presentation: The son of this family presented ectodermal defects (thin and sparse hair, mild nail dysplasia), tetramelic ectrodactyly, syndactyly, and nasolacrimal duct obstruction (NLDO), indicative of an EEC3 diagnosis. His father, however, exhibited severe NLDO, facial freckling, dental abnormalities, mild nail dysplasia, and a history of micturition problems, compatible with ADULT syndrome. Both were heterozygous for the NM_003722.5(TP63):c.797G>A (p.Arg266Gln) pathogenic variant in TP63. Discussion: This report expands the spectrum of intrafamilial variability confirming that this can include the expression of distinct types of TP63-related disorders among different members of the same family, whose implications should be also considered in genetic counseling. From our review, we observed that p.Arg266Gln variant seems to correlate particularly with the presence of NLDO, sparse hair/eyebrows, ridged/dystrophic nails, anodontia/hypodontia, and micturition difficulties, as well as for a minor frequency of cleft lip/cleft palate.

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Split-hand/foot malformation (SHFM) is a genetically heterogeneous congenital limb reduction defect characterized by the deficiencies of central rays of the autopod. Tandem duplications at 10q24 locus account for approximately 20% of all SHFM cases. Here, we report five affected individuals from four unrelated Indian families with SHFM3 caused by microduplication of 10q24 locus showing varied clinical presentations. This report substantiates and extends the current understanding of this rare, multifaceted, and complex condition.

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BACKGROUND: Ectrodactyly is a rare congenital limb malformation characterized by a deep median cleft of the hand and/or foot due to the absence of central rays. It could be isolated or depicts a part of diverse syndromic forms. Heterozygous pathogenic variants in the TP63 gene are responsible for at least four rare syndromic human disorders associated with ectrodactyly. Among them, ADULT (Acro-Dermato-Ungual-Lacrimal-Tooth) syndrome is characterized by ectodermal dysplasia, excessive freckling, nail dysplasia, and lacrimal duct obstruction, in addition to ectrodactyly and/or syndactyly. Ophthalmic findings are very common in TP63-related disorders, consisting mainly of lacrimal duct hypoplasia. Absent meibomian glands have also been well documented in EEC3 (Ectrodactyly Ectodermal dysplasia Cleft lip/palate) syndrome but not in ADULT syndrome. METHODS: We report a case of syndromic ectrodactyly consistent with ADULT syndrome, with an additional ophthalmic manifestation of agenesis of meibomian glands. The proband, as well as her elder sister, presented with congenital cone dystrophy.The molecular investigation was performed in the proband using Whole Exome Sequencing. Family segregation of the identified variants was confirmed by Sanger sequencing. RESULTS: Two clinically relevant variants were found in the proband: the novel de novo heterozygous missense c.931A > G (p.Ser311Gly) in the TP63 gene classified as pathogenic, and the homozygous nonsense pathogenic c.1810C > T (p.Arg604Ter) in the CNGB3 gene. The same homozygous CNGB3 variation was also found in the sister, explaining the cone dystrophy in both cases. CONCLUSIONS: Whole Exome Sequencing allowed dual molecular diagnoses: de novo TP63-related syndromic ectrodactyly and familial CNGB3-related congenital cone dystrophy.

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Background: Split-hand/foot malformation type 1 (SHFM1) refers to the group of rare congenital limb disorders defined by the absence or hypoplasia of the central rays of the autopods with or without accompanying anomalies, such as hearing loss, craniofacial malformation, and ectodermal dysplasia. Consequently, the condition is characterized by clinical variability that hinders diagnostic and counseling procedures. SHFM1 is caused by pathogenic variants affecting the DLX5/6 genes and/or their tissue-specific enhancers at the 7q21.3 locus. Herein, we report on seven patients from five unrelated Polish families affected by variable symptoms of the SHFM1 spectrum, all harboring 7q21.3 or 7q21.2-q21.3 rearrangements, and provide a genotype-phenotype correlation in the studied cohort. Methods: We applied GTG banding, array-based comparative genomic hybridization (aCGH), and whole-genome sequencing (WGS) in order to identify the causative aberrations in all affected patients. Results: The identified pathogenic structural variants included deletions and/or translocations involving the 7q21.3 locus, i.e., t(7;10)(q21.3;q22.2) and t(7;12)(q21.3;q21.2) in all affected individuals. Interestingly, a sporadic carrier of the latter aberration presented the SHFM1 phenotype with additional features overlapping with Baker-Gordon syndrome (BAGOS), which resulted from the translocation breakpoint at chromosome 12 within the SYT1 gene. Conclusion: Clinical variability of the studied cohort reflects the composition of the DLX5/6 regulatory elements that were dislocated from their target genes by chromosomal rearrangements. The correlation of our data with the previously published observations enabled us to update the phenotypic subregions and regulatory units within the SHFM1 locus. In addition, we present the first case of SHFM1 and BAGOS-like phenotype that resulted from translocation breakpoints at chromosomes 7 and 12, both of which were pathogenic, and consequently, we show the first evidence that BAGOS can also result from the regulatory loss-of-function SYT1 mutations. In this paper, we emphasize the utility of sequence-based approaches in molecular diagnostics of disorders caused by regulatory structural variants.

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The ectrodactyly-ectodermal dysplasia-clefting syndrome is an extremely rare genetic disorder that is inherited as an autosomal dominant trait, but can also occur sporadically. It is characterized by the triad of ectrodactyly (absence of fingers), ectodermal dysplasia and cleft lip and palate along with variable involvement of other organs. Both the ectodermal and mesodermal tissues may be affected resulting in a spectrum of phenotypes. Early diagnosis and treatment signify a unique challenge for those involved in the clinical management, while enable counseling and preparation of parents for the tasks ahead of them. In our report, we describe the case of a patient with sporadic EEC syndrome. In addition to the presentation of the complex phenotype along with the medical interventions, we summarize the most important characteristics of the disease, the diagnostic and therapeutic possibilities as well as the clinical significance of the accurate genetic verification. Using whole exome sequencing, we identified in the 3q28 chromosomal region a pathogenic mutation within the TP63 gene previously linked to the EEC3 phenotypes. The knowledge of pathogenic mutation provides the means to prenatal diagnostics or in vitro fertilization methods that allows us to minimize the possibility of inheriting the syndrome in the patient's offspring. By presenting our case, we aim to draw attention to this rare and disabling disease that requires the high quality works of a multidisciplinary team capable of ensuring good quality of life for the patient. Orv Hetil. 2023; 164(46): 1831-1837.

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BACKGROUND: The diagnostic process for children and adults manifesting a constellation of ectodermal abnormalities requires a conscientious and highly structured process. MATERIAL AND METHODS: Six girls (aged 6-month-8 years) and two older girls (aged 13 and 16 years) were born with variable skin lesions of varying intensities associated with noticeable cranial and skeletal malformation complexes. Cleft palate, abnormal dentition, and multiple papillomas were evident around the mouth, mostly bilateral but asymmetrical in the upper and lower limbs. Exaggerated frontal bossing (macrocephaly) and in some patients' microcephaly with variable skeletal defects of the craniocervical junction and diverse forms of lower limb deformities of syndactyly, polydactyly, and split-hand/foot (ectrodactyly). RESULTS: All patients manifested the constellation of abnormalities with variable intensities ranging between alopecia, papillomas, striated skin pigmentations split-hand/foot (ectrodactyly), and major bone defects. A 3D reconstruction CT scan was directed mainly to further scrutinize children with pseudo cleft lip, submucus cleft, and cleft palate. Interstingly, they manifested massive demineralization of the cranium associated with severely defective dentition. A spine 3D reconstruction CT scan in two girls showed marked cystic cavitation of the upper jaw associated with excessive cavitation of the mastoid, causing tremendous frailty of the mastoid bone. A 3D sagittal CT scan showed odontoid hypoplasia and C1-2 instability associated with the rudimentary atlas and the persistence of extensive synchondrosis of the cervico-thoracic spine. The overall clinical and radiological phenotypic characterizations were consistent with the diagnosis of focal dermal hypoplasia (Goltz syndrome). Two children manifested heterozygous mutations in the PORCN gene, chromosome Xp11. CONCLUSIONS: In this study, we believe it's a good opportunity to share our novel scientific findings, which are intriguing and can be inspiring to readers, and to further aid the current scientific literature with exceptionally new unveiling results. This is the first comprehensive study of the cranio-skeletal malformation complex in children with GS.

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OBJECTIVE: Prenatal diagnosis of the Ectrodactyly-Ectodermal dysplasia-clefting (EEC) syndrome has been based upon the detection of ectrodactyly, in association with facial clefting and/or positive family history. Our aim is to describe other ultrasonographic features indicating the presuntive diagnosis, regardless of genetic diagnosis, especially in cases of negative family history. MATERIALS AND METHODS: A case report and a review of the literature was assessed. RESULTS: Our case report showed a singleton foetus "lobster claw" deformities of hands and feet. Paternal history revealed bilateral agenesia of two fingers. Through literature, 15 case reports of prenatal diagnosis of EEC syndrome were found, 14 of which were eligible for our systematic review. The 33% of cases (5/15) had a familiar history of EEC, thus, we found one case of consanguinity of parents. Anomalies EEC-related were recognized in the 40% of cases (6/15). An association with genitourinary anomalies was found in 30% (5/15) of them. CONCLUSIONS: A strong suspicion of final diagnosis of EEC may be done in the presence of ectrodactyly, facial clefting and urinary malformation especially in cases of negative family history. More attention should be given to a genetic counseling, especially to understand a possible relation to other genetic syndromes.

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Split Hand-Foot Malformation (SHFM) is a congenital limb defect characterized by a median cleft of the hands and/or feet due to the absence/hypoplasia of the central rays. It may occur as part of a syndromic condition or as an isolated malformation. The most common of the six genetic loci identified for this condition is correlated to SHFM1 and maps in the 7q21q22 region. SHFM1 is characterized by autosomal dominant transmission, incomplete penetrance and variable expressivity. Associated features often include hearing loss, intellectual disability/developmental delay and craniofacial abnormalities. Disruption of the DLX5/DLX6 genes, mapping within the SHFM1 locus, is now known to be responsible for the phenotype. Through SNP array, we analyzed a patient affected by SHFM1 associated with deafness and an abnormality of the inner ear (incomplete partition type I); we identified a deletion in 7q21, not involving the DLX5/6 genes, but including exons 15 and 17 of DYNC1I1, known to act as exonic enhancers (eExons) of the DLX5/6 genes. We further demonstrated the role of DYNC1I1 eExons in regulating DLX5/6 expression by means of showing a reduced expression of the DLX5/6 genes through RT-PCR in a patient-derived lymphoblastoid cell line. Furthermore, our data and a review of published cases do not support the hypothesis that DLX5/6 are imprinted in humans. This work is an example of how the disruption of regulatory elements can be responsible for congenital malformations.

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Ocular manifestations are common associations of ectrodactyly-Ectodermal dysplasia-cleft palate (EEC) syndrome. We would like to report a case of a 48-year-old patient with EEC syndrome who manifested ocular and extraocular signs and symptoms. The ophthalmic findings in this patient included chronic blepharitis and absence of meibomian gland. There was also a presence of hazy cornea with vascularized corneal stroma and symblepharon involving the lower lid. Systemic conditions showed generalized dry and scaly skin with hand-foot split deformity. Therefore, ophthalmologists should be alert to spot and diagnose this condition as prompt treatment should be commenced considering this can be sight-threatening.

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SHFM (Split Hand/Foot Malformation) is a heterogeneous group of disorders characterized by the presence of clefts in the hands and feet, along with syndactyly of the digits. In this article, we describe a family in which two members exhibit characteristic developmental abnormalities associated with SHFM, presenting with variable clinical features. Using whole-genome sequencing, we identified a microduplication of a chromosomal segment on locus 10q24.32, specifically spanning positions 102934495 to 103496555, encompassing genes BTRC, POLL, FBXW4 and LBX1 in the proband. Genomic duplications, including these genes, were previously described in patients diagnosed with the third type of SHFM. We validated the presence of this structural rearrangement in 7 family members, including the proband and the proband's father. Remarkably, further investigation demonstrated that the detected duplication exhibits a mosaic state in the phenotypically normal paternal grandmother of the proband, thereby providing a plausible explanation for the absence of a pathological phenotype in her.

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Resumen ANTECEDENTE: El síndrome de Karsch-Neugebauer o ectrodactilia del pie o pie hendido, es una enfermedad congénita sumamente rara, caracterizada por aplasia-hipoplasia de las falanges y metatarsianos del pie. Cuando aparece de forma aislada se debe a una forma autosómica dominante de expresión variable, aunque también puede ser de carácter autosómico recesivo. CASO CLÍNICO: Paciente de 31 años, sin antecedentes heredofamiliares de importancia, con IMC de 25.95 kg/m2, signos vitales en parámetros normales. Con dos embarazos, cesárea previa sin complicaciones. El ultrasonido estructural 20 a 23.6 semanas del embarazo actual reportó un feto vivo, de sexo femenino y 22.2 semanas de gestación, con múltiples alteraciones anatómicas: arteria umbilical única, hueso nasal hipoplásico, micrognatia en ángulo facial y miembros inferiores con ectrodactilia bilateral. CONCLUSIONES: Los estudios ultrasonográficos, en especial el de las semanas 20 a 23.6 de gestación son decisivos para la detección de malformaciones congénitas. Sin embargo, a partir de las 11 a 13.6 semanas es posible establecer diagnósticos estructurales de manera temprana. Muchas alteraciones y síndromes, como el de Karsch-Neugebauer, suelen ser incapacitantes y al combinarse con otras anomalías pueden llegar a ser incompatibles con la vida. Se requieren diagnósticos tempranos para la toma de decisiones de manera consensuada con la familia y el equipo multidisciplinario.

Abstract BACKGROUND: Karsch-Neugebauer syndrome, or ectrodactyly of the foot or cleft foot, is an extremely rare congenital disorder characterized by aplasia-hypoplasia of the phalanges and metatarsals of the foot. When it occurs in isolation, it is due to an autosomal dominant form of variable expression, although it can also be autosomal recessive. CLINICAL CASE: 31-year-old female patient with no significant hereditary family history, BMI of 25.95 kg/m2, vital signs within normal parameters. With two pregnancies, previous caesarean section without complications. Structural ultrasound 20 to 23.6 weeks of the current pregnancy showed a live fetus, female sex and 22.2 weeks gestation, with multiple anatomical anomalies: single umbilical artery, hypoplastic nasal bone, micrognathia in the facial angle and lower limbs with bilateral ectrodactyly. CONCLUSIONS: Ultrasound examinations, especially at 20 to 23.6 weeks of gestation, are crucial for the detection of congenital malformations. However, from 11 to 13.6 weeks it is possible to make early structural diagnoses. Many disorders and syndromes, such as Karsch-Neugebauer syndrome, are often disabling and, in combination with other anomalies, can become incompatible with life. Early diagnosis is necessary to make informed decisions with the family and the multidisciplinary team.

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BACKGROUND: Split-hand/ foot malformation with long bone deficiency 3 (SHFLD3) is an extremely rare condition associated with duplications located on 17p13.3, which invariably encompasses the BHLHA9 gene. The disease inherits with variable expressivity and significant incomplete penetrance as high as 50%. RESULTS: We have detected 17p13.3 locus one-allele triplication in a male proband from family 1 (F1.1), and duplication in a male proband from family 2 (F2.1) applying array comparative genomic hybridization (array CGH). The rearrangements mapped to the following chromosomal regions-arr[GRCh38] 17p13.3(960254-1291856)×4 in F1.1 and arr[GRCh38] 17p13.3(1227482-1302716)×3 in F2.1. The targeted quantitative PCR revealed that the 17p13.3 locus was also duplicated in the second affected member from family 2 (F2.2; brother of F2.1). In the next step, we performed segregation studies using quantitative PCR and revealed that F1.1 inherited the triplication from his healthy father-F1.2, whereas the locus was unremarkable in the mother of F2.1 & F2.2 and the healthy son of F2.1. However, the duplication was present in a healthy daughter of F2.2, an asymptomatic carrier. The breakpoint analysis allowed to define the exact size and span of the duplicated region in Family 2, i.e., 78,948 bp chr17:1225063-1304010 (HG38). Interestingly, all symptomatic carriers from both families presented with variable SHFLD3 phenotype. The involvement of secondary modifying locus could not be excluded, however, the Sanger sequencing screening of BHLHA9 entire coding sequence was unremarkable for both families. CONCLUSIONS: We have shed light on the one-allele CNV triplication occurrence that should be considered when a higher probe (over duplication range) signal is noted. Second, all SHFLD3 patients were accurately described regarding infrequent limb phenotypes, which were highly variable even when familial. Of note, all symptomatic individuals were males. SHFLD3 still remains a mysterious ultra-rare disease and our findings do not answer crucial questions regarding the disease low penetrance, variable expression and heterogeneity. However, we have presented some clinical and molecular aspects that may be helpful in daily diagnostic routine, both dysmorphological and molecular assessment, of patients affected with SHFLD3.

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