Genetic blueprint of congenital muscular dystrophies with brain malformations in Egypt: A report of 11 families.

Congenital muscular dystrophies (CMDs) are a group of rare muscle disorders characterized by early onset hypotonia and motor developmental delay associated with brain malformations with or without eye anomalies in the most severe cases. In this study, we aimed to uncover the genetic basis of severe CMD in Egypt and to determine the efficacy of whole exome sequencing (WES)-based genetic diagnosis in this population. We recruited twelve individuals from eleven families with a clinical diagnosis of CMD with brain malformations that fell into two groups: seven patients with suspected dystroglycanopathy and five patients with suspected merosin-deficient CMD. WES was analyzed by variant filtering using multiple approaches including splicing and copy number variant (CNV) analysis. We identified likely pathogenic variants in FKRP in two cases and variants in POMT1, POMK, and B3GALNT2 in three individuals. All individuals with merosin-deficient CMD had truncating variants in LAMA2. Further analysis in one of the two unsolved cases showed a homozygous protein-truncating variant in Feline Leukemia Virus subgroup C Receptor 1 (FLVCR1). FLVCR1 loss of function has never been previously reported. Yet, loss of function of its paralog, FLVCR2, causes lethal hydranencephaly-hydrocephaly syndrome (Fowler Syndrome) which should be considered in the differential diagnosis for dystroglycanopathy. Overall, we reached a diagnostic rate of 86% (6/7) for dystroglycanopathies and 100% (5/5) for merosinopathy. In conclusion, our results provide further evidence that WES is an important diagnostic method in CMD in developing countries to improve the diagnostic rate, management plan, and genetic counseling for these disorders.

"Lowe syndrome: A particularly severe phenotype without clinical kidney involvement".

Lowe syndrome (LS) is a very rare disorder of phosphatidylinositol metabolism, which manifests with a complex phenotype comprising a clinical triad encompassing major abnormalities of the eyes, the kidneys, and the central nervous system. We are reporting a 23-year-old Egyptian male with a severe phenotype of LS with a minimal kidney disease. Direct sequencing of the OCRL gene detected a p.His375Arg mutation in the catalytic domain of the protein. The patient suffered from bilateral congenital cataracts and glaucoma, striking growth deficiency, severe psychomotor disability, a severe osteopathy, and seizures, but only minimal renal dysfunction. Although the biological mechanisms underlying the pathophysiology of LS manifestations is yet unclear, it has been proposed that growth delay and osteopathy are linked to a renal dysfunction. This report, however, argues this association and suggests that kidney dysfunction may partially explain the growth deficiency and bone abnormalities, but other still undefined factors might have a potential impact.

A Novel Homozygous Frameshift Mutation in CCN6 Causing Progressive Pseudorheumatoid Dysplasia (PPRD) in a Consanguineous Yemeni Family.

Background: Progressive pseudorheumatoid dysplasia (PPRD) inherited in an autosomal recessive fashion, is a disabling disease, characterized by platyspondyly, irregularities of the vertebral bodies, narrowing of the intervertebral discs and intraarticular spaces, widening of the epiphysis-metaphysis, polyarthralgia, multiple joint contractures, and disproportionate short stature. A number of studies have been performed on this deformity in various populations around the globe, including the Arab population. Mutations in CCN6, located on 6q22, are reported to cause this anomaly. Case Presentation: The present study describes the investigation of a consanguineous family of Yemeni origin. Clinical examination of the patient revealed short stature with progressive skeletal abnormalities, stiffness and enlargement of small joints of the hands along with restriction of movements of proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints with weakness and gait disturbance. Sanger sequencing revealed a novel homozygous frameshift deletion mutation (c.746delT; p.Val249Glyfs*10) in CCN6 which may lead to NMD (Nonsense mediated decay). This mutation expands the spectrum of pathogenic variants in CCN6 causing PPRD.

Overlap between Fibular Aplasia, Tibial Campomelia, and Oligosyndactyly and Fuhrmann's Syndromes in an Egyptian Female Infant.

We report a rare congenital limb defect with combined features of both fibular aplasia, tibial campomelia, and oligosyndactyly (FATCO) and Fuhrmann's syndromes. A female newborn infant, born to nonconsanguineous Egyptian parents, presented with isolated abnormalities of the lower limbs comprising bilateral shortening and anterior bowing of the lower limbs at the distal third of the tibia and split foot. Radiographic examination revealed complete absence of both fibulae, anterolateral bowing and shortening of the tibia, bowing of the femora, and absence of several metatarsal and phalangeal bones. The upper limbs were clinically and radiologically normal, and the infant had neither facial dysmorphism nor other associated visceral anomalies. The presented case highlights an extremely rare limb deficiency syndrome, and together with additional case reports, it could be useful to further delineate this condition.