Expanding the Epidemiological and Phenotypic Spectrum of MEGDEL Syndrome: The First Case Report From Egypt.

MEGDEL syndrome is a rare autosomal recessive disease characterized by 3-methylglutaconic aciduria, deafness-dystonia, hepatopathy, encephalopathy, and leigh-like syndrome, which results from biallelic pathogenic variants in SERAC1 gene. The diagnosis is commonly challenging due to the diverse clinical manifestations. Herein, we report the first case of MEGDEL syndrome from the Egyptian population. This is a 7-year-old boy born to first cousins Arab parents from Egypt with family history of unexplained deaths of 3 siblings during the neonatal period. He presented with developmental regression since the age of 2 years resulting in marked muscle weakness with no head support, generalized spasticity more prominent in lower limbs, and aphonia, but intact hearing. The child had excessive urinary excretion of 3-methylglutaconic acid, and his brain magnetic resonance imaging showed characteristic basal ganglia affection with "Putaminal eye sign." Whole-exome sequencing demonstrated a likely pathogenic homozygous c.1404-2A>G variant in SERAC1 gene. This report expands the epidemiological and phenotypic spectrum of MEGDEL syndrome by reporting the first case from the Egyptian population who had relatively delayed onset and no evident hepatopathy or deafness.