A rare cause of intellectual disability: Novel mutations of NFIX gene in two patients with clinical features of Marshall-Smith syndrome and Malan syndrome.

Marshall-Smith syndrome (MSS) and Malan syndrome (MS) are both allelic disorders caused by mutations in the NFIX gene. MS is characterized by overgrowth, intellectual disability, distinctive facial features, and accelerated skeletal maturation. On the other hand, clinical features of MSS consist of advanced bone age, dysmorphic features, intellectual disability, and failure to thrive at birth. In this study, we presented the clinical and molecular findings of two different patients with MS and MSS as a rare cause of intellectual disability and reported two novel variants in the NFIX gene. NFIX gene sequencing revealed a novel heterozygous c.1287delC (p.G430Vfs*34) mutation in patient 1 whose clinical diagnosis was compatible with Marshall-Smith syndrome, and in the second patient, physical features consistent with Malan syndrome, was detected a heterozygous one nucleotide duplication, c.303dupC (pCys102LeufsTer17).

Spondyloepimetaphyseal dysplasia-Maroteaux type due to dominant TRPV4 mutation: expanding the phenotype with a case report.

INTRODUCTION: Dominant pathogenic mutations in the TRPV4 gene give rise to a wide spectrum of abnormal phenotypes, including bone dysplasia as well as spinal muscular atrophy and hereditary motor and sensory neuropathy. Spondyloepimetaphyseal dysplasias (SEMDs) are autosomal dominant skeletal dysplasias characterized by mild epiphyseal dysplasia, flared metaphyses, prominent joints, spondyler dysplasia, and brachydactyly with various carpal, metacarpal, and finger malformations. CASE PRESENTATION: We present a boy who has the clinical and radiological signs of SEMD-M with a dominant TRPV4 mutation. He also has some striking findings that have not been seen in these patients before, and they may be able to provide assistance to medical professionals in the process of diagnosis.These include a shorter distance between his lumbar vertebrae, congenital contractures, and an arachnoid cyst.