Genotypic and phenotypic spectrum of Galloway-Mowat syndrome in Kuwait

Galloway-Mowat syndrome (GAMOS) is a rare genetic disorder that is characterized by microcephaly and neurological and renal abnormalities. Ten types of GAMOS exist based on the underlying implicated gene. The purpose of this study was to investigate the phenotypic and genotypic spectrum of GAMOS in Kuwait.

We queried the Kuwait Medical Genetic Center database for subjects with neuro-renal or neurological phenotypes and pathogenic variants in any of the ten known genes associated with GAMOS.

We identified eight subjects from five unrelated families with biallelic pathogenic WDR73 variants and a diagnosis of GAMOS type 1 (GAMOS1). All subjects had global developmental delay, microcephaly, tone abnormalities and impaired activities of daily living. Renal features were observed in more than half of the subjects (5/8 subjects) and included proteinuria, nephrotic syndrome, and end-stage renal disease (ESRD). More than half of the subjects (5/8 subjects) died by 5-10 due to ESRD, including one of which who died due to unknown cause while the rest (ages 3-5 years) are still living with no renal features.Two possible founder variants were identified, including c.287 G>A;p.Arg96Lys in three unrelated families of Kuwaiti, Iraqi, and/or Syrian ancestry, and c.767 G>A;p.Arg256Gln in two unrelated families of Kuwaiti or Syrian ancestry.

GAMOS1 is the most prevalent form of GAMOS in Kuwait, likely due to the presence of two WDR73 regional founder variants. These findings contribute to the global understanding of GAMOS and highlight the important contribution of regional genetic studies in diverse populations to rare disease research.