Identification of a novel homozygous UNC80 variant in a child with infantile hypotonia with psychomotor retardation and characteristic facies-2 (IHPRF2).

The UNC80 gene encodes for a large component of the NALCN sodium-leak channel complex that regulates the basal excitability of the nervous system. In this study, we report on a novel homozygous mutation in UNC80 in a Palestinian-Emirati patient suffering infantile hypotonia with psychomotor retardation and characteristic facies. This mutation was detected by whole exome sequencing and confirmed using Sanger sequencing in the patient-parents trio. Numerous elements in the patient's phenotype were in agreement with the few reported cases of UNC80 mutations; however there are some notable differences. We present comprehensive clinical and molecular accounts of this mutation in addition to a full review of previously reported patients of UNC80 mutations.