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Abnormal hyperpolarization of the KCNK4 gene, expressed in the nervous system, brain, and periodontal ligament fibroblasts, leads to impaired neurotransmitter sensitivity, cardiac arrhythmias, and endocrine dysfunction, as well as, progressive cell proliferation. De novo gain of function variants in the KCNK4 gene were reported to cause a recognizable syndrome characterized by facial dysmorphism, hypertrichosis, epilepsy, intellectual/developmental delay, and gingival overgrowth (FHEIG, OMIM# 618381). FHEIG is extremely rare with only three reported cases in the literature. Herein, we describe the first inherited KCNK4 variant (c.730G>C, p.Ala244Pro) in an Egyptian boy and his mother. Variable phenotypic expressivity was noted as the patient presented with the full‐blown picture of the syndrome while the mother presented only with hypertrichosis and gingival overgrowth without any neurological manifestations. The c.730G>C (p.Ala244Pro) variant was described before in a single patient and when comparing the phenotype with our patient, a phenotype–genotype correlation seems likely. Atrial fibrillation and joint laxity are new associated findings noted in our patient extending the clinical phenotype of the syndrome. Dental management was offered to the affected boy and a dramatic improvement was noted as the patient regained his smile, restored the mastication function, and resumed his psychological stability. [ABSTRACT FROM AUTHOR]

Abstract Brachydactyly ("short digits") is a general term that refers to disproportionately short fingers and toes, and forms part of the group of limb malformations characterized by bone dysostosis. The various types of isolated brachydactyly are rare, except for types A3 and D. Brachydactyly can occur either as an isolated malformation or as a part of a complex malformation syndrome. To date, many different forms of brachydactyly have been identified. Some forms also result in short stature. In isolated brachydactyly, subtle changes elsewhere may be present. Brachydactyly may also be accompanied by other hand malformations, such as syndactyly, polydactyly, reduction defects, or symphalangism. For the majority of isolated brachydactylies and some syndromic forms of brachydactyly, the causative gene defect has been identified. In isolated brachydactyly, the inheritance is mostly autosomal dominant with variable expressivity and penetrtance. Diagnosis is clinical, anthropometric and radiological. Prenatal diagnosis is usually not indicated for isolated forms of brachydactyly, but may be appropriate in syndromic forms. Molecular studies of chorionic villus samples at 11 weeks of gestation and by amniocentesis after the 14th week of gestation can provide antenatal diagnosis if the causative mutation in the family is known. The nature of genetic counseling depends both on the pattern of inheritance of the type of brachydactyly present in the family and on the presence or absence of accompanying symptoms. There is no specific management or treatment that is applicable to all forms of brachydactyly. Plastic surgery is only indicated if the brachydactyly affects hand function or for cosmetic reasons, but is typically not needed. Physical therapy and ergotherapy may ameliorate hand function. Prognosis for the brachydactylies is strongly dependent on the nature of the brachydactyly, and may vary from excellent to severely influencing hand function. If brachydactyly forms part of a syndromic entity, prognosis often depends on the nature of the associated anomalies.

Postaxial polydactyly (PAP) is a frequent limb malformation consisting in the duplication of the fifth digit of the hand or foot. Morphologically, this condition is divided into type A and B, with PAP‐B corresponding to a more rudimentary extra‐digit. Recently, biallelic truncating variants in the transcription factor GLI1 were reported to be associated with a recessive disorder, which in addition to PAP‐A, may include syndromic features. Moreover, two heterozygous subjects carrying only one inactive copy of GLI1 were also identified with PAP. Herein, we aimed to determine the level of involvement of GLI1 in isolated PAP, a condition previously established to be autosomal dominantly inherited with incomplete penetrance. We analyzed the coding region of GLI1 in 95 independent probands with nonsyndromic PAP and found 11.57% of these subjects with single heterozygous pathogenic variants in this gene. The detected variants lead to premature termination codons or result in amino acid changes in the DNA‐binding domain of GLI1 that diminish its transactivation activity. Family segregation analysis of these variants was consistent with dominant inheritance with incomplete penetrance. We conclude that heterozygous changes in GLI1 underlie a significant proportion of sporadic or familial cases of isolated PAP‐A/B. [ABSTRACT FROM AUTHOR]

GAPO syndrome is a very rare disorder characterized by growth retardation, alopecia, pseudoanodontia and progressive optic atrophy. It is caused by biallelic mutations in the ANTXR1 gene. Herein, we describe the clinical and molecular findings of seven new patients with GAPO syndrome. Our patients presented with the characteristic clinical features of the syndrome except for one patient who did not display total alopecia till the age of two years. Strikingly, optic atrophy and glaucoma were observed in all patients and one patient showed keratopathy in addition. Moreover, craniosynstosis was an unusual associated finding in one patient. Mutational analysis of ANTXR1 gene identified five novel homozygous mutations including two frameshift, two splice site and a large intragenic deletion of exon 3. Our results reinforce the clinical characteristics of the syndrome, expand the mutational spectrum and provide more insights into the role of the ANTXR1 protein in the regulation of extracellular matrix. [ABSTRACT FROM AUTHOR]

We report two unrelated boys with frontonasal dysplasias type‐2 (FND‐2) who shared an identical novel homozygous ALX4 mutation c.291delG (p.Q98Sfs*83). Both patients presented with a large skull defect but one had bilateral parietal meningocele‐like cysts that lie along with the bony defect and increased in size with age. Scalp alopecia, hypertelorism, and clefted alae nasi were also detected in both of them. Furthermore, impalpable gonads were noted, being unilateral in one and bilateral in the other. Neuroimaging showed small dysplastic occipital lobes with dysgyria and midline subarachnoid cyst. Additional dysplastic corpus callosum and small cerebellar vermis were observed in one patient. Parietal foramina were noted in the parents of one patient. Our findings highlight the dosage effect of ALX4 and underscore the challenges of prenatal genetic counseling. Further, the indirect role of ALX4 in the development of the occipital lobe and posterior fossa is discussed. [ABSTRACT FROM AUTHOR]

Background Osteogenesis imperfecta ( OI) is a heterogeneous bone disorder characterized by recurrent fractures. Although most cases of OI have heterozygous mutations in COL1A1 or COL1A2 and show autosomal dominant inheritance, during the last years there has been an explosion in the number of genes responsible for both recessive and dominant forms of this condition. Herein, we have analyzed a cohort of patients with OI, all offspring of unaffected parents, to determine the spectrum of variants accounting for these cases. Twenty patients had nonrelated parents and were sporadic, and 21 were born to consanguineous relationships. Methods Mutation analysis was performed using a next-generation sequencing gene panel, homozygosity mapping, and whole exome sequencing ( WES). Results Patients offspring of nonconsanguineous parents were mostly identified with COL1A1 or COL1A2 heterozygous changes, although there were also a few cases with IFITM5 and WNT1 heterozygous mutations. Only one sporadic patient was a compound heterozygote for two recessive mutations. Patients offspring of consanguineous parents showed homozygous changes in a variety of genes including CRTAP, FKBP10, LEPRE1, PLOD2, PPIB, SERPINF1, TMEM38B, and WNT1. In addition, two patients born to consanguineous parents were found to have de novo COL1A1 heterozygous mutations demonstrating that causative variants in the collagen I structural genes cannot be overlooked in affected children from consanguineous couples. Further to this, WES analysis in probands lacking mutations in OI genes revealed deleterious variants in SCN9A, NTRK1, and SLC2A2, which are associated with congenital indifference to pain ( CIP) and Fanconi-Bickel syndrome ( FBS). Conclusion This work provides useful information for clinical and genetic diagnosis of OI patients with no positive family history of this disease. Our data also indicate that CIP and FBS are conditions to be considered in the differential diagnosis of OI and suggest a positive role of SCN9A and NTRK1 in bone development. [ABSTRACT FROM AUTHOR]

We describe five patients from three different families with microcephalic osteodysplastic primordial dwarfism type I (MOPD I), which was molecularly confirmed by homozygosity for the g.51G >A and g.55G >A mutations in RNU4ATAC, respectively. The patients showed the classical phenotype and demonstrated in addition variable degrees of gyration abnormalities and malformations of the callosal body with an interhemispheric cyst. One patient also showed underdevelopment of the cerebellar vermis. This confirms that cortical malformations should be considered cardinal manifestations of MOPD I. Oculocutaneous albinism, brain hemorrhage and chilblains have been found to be associated with MOPD I. The present study showed lack of retinal pigmentation in three patients of whom two had an unusually fair complexion of hair and skin. One patient was found to have a hematoma in the left thalamus. This may indicate that both pigmentary abnormalities and vascular anomalies may be part of the phenotype of MOPD I as well. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Background: Achondroplasia is the most common form of non lethal skeletal dysplasia. It is a fully penetrant autosomal dominant disorder and the majority of cases are sporadic resulting from de novo mutations associated with advanced paternal age. The phenotype of achondroplasia is related to disturbance in endochondral bone formation due to mutations in the fibroblast growth factor receptor-3 (FGFR3) gene. Aim of the Work: Evaluation of the cardinal phenotypic features in achondroplasia, the body physique using anthropometric measurements, the characteristic radiological signs in the patients as a main tool for diagnosis and detection of the most common mutations in achondroplasia patients in the studied sample. Subjects and Methods: From 42 cases referred to us as achondroplasia, we selected 20 cases where clinical manifestations were consistent with achondroplasia. Cases were subjected to full clinical examination, detailed anthropometric measurements, whole body skeletal survey and molecular studies of the most common mutations of the FGFR3 gene using PCR amplification technique. Results: Nineteen cases were sporadic (95%) and one case had an affected father (5%). A paternal age above 35 years at the time of child's birth was present in 7 cases (35%). Paternal exposure to occupational heat was noted in 6 cases (30%) and parental exposure to chemicals in 3 cases (15%). All cases showed typical clinical and radiological manifestations of achondroplasia. Anthropometric measurements quantitatively confirmed the body physique in the studied cases. G380R common mutations of the FGFR3 gene were detected in 15/18 cases (83%) with the G to A transition at nucleotide 1138 in 14 cases (77%). Agenesis of corpus callosum, not previously reported in association with achondroplasia, was present in the only case with the G-C transversion mutation at nucleotide 1138 (5%). Conclusions: Awareness of the cardinal features of achondroplasia, proper anthropometric measurements and detailed skeletal survey are the key for accurate diagnosis, genetic counseling and avoidance of over diagnosis. The majority of studied Egyptian achondroplasia patients have the same common mutation that has been most often defined in patients with achondroplasia from other countries. [ABSTRACT FROM AUTHOR]