WDR59 Is Mutated in Individuals With Autosomal Recessive Syndromic Dilated Cardiomyopathy.

Pediatric dilated cardiomyopathy (DCM) carries high morbidity and mortality, with up to half of cases genetically unexplained. The mTORC1 nutrient sensing pathway is a critical regulator of cardiomyocyte homeostasis, yet no Mendelian DCM genes have been linked to its upstream regulator, GATOR2. WDR59 encodes a core WD-repeat subunit of GATOR2, but its cardiac role is unknown. We recruited six affected individuals from four unrelated families presenting with early-onset, severe autosomal recessive syndromic DCM. Affected children developed left ventricular dilation, variably accompanied by cataracts, dysmorphic facial features, and growth and developmental delay. Saudi patients mapped to a single locus and shared therein a homozygous founder WDR59 variant: c.2887G>A (p.Gly963Arg). The French patient was compound heterozygous for two variants (NM_030581.4:c.966+3A>G and NM_030581.4:c.886+1219T>G) and their deleterious splicing effect was confirmed by RNA-seq. We propose WDR59 as a novel autosomal recessive DCM gene and implicate dysregulated GATOR2-mTORC1 signaling as the underlying mechanism. Future validation is needed to confirm this link and investigate whether restoring mTORC1-autophagy balance can ameliorate WDR59-related cardiac dysfunction.