Two non-familial cases of Galloway-Mowat syndrome carrying the homozygous mutations of WDR73 and TP53RK

Abstract

Galloway–Mowat syndrome (GAMOS) is a rare hereditary disease manifested as a combination of nephrotic syndrome and central nervous system impairment. To date, many GAMOS cases attributed to various gene mutations have been reported such as WHAMM, NUP107, WDR73, OSGEP, and TP53RK. We detected two novel homozygous mutations of WDR73 ‘’NM_032856:c.G287A:p.R96K‘’ and TP53RK ‘’NM_033550:c.A193O:p.K65Q‘’ in two female kids of the consanguineous parents from different families using whole exome sequencing. Both patients almost manifested similar neurodegenerative phenotypes, including developmental delay, microcephaly, hypotonia, and brain atrophy on magnetic resonance imaging during infancy. WDR73-positive GAMOS case manifested a late-onset minimal nephrotic syndrome at the age 4 years while TP53RK-positive case presented nephrotic syndrome at the age 1 which progressed to steroid-resistant nephrotic syndrome due to lack of remission after 4-6 weeks of initial treatment with prednisone. Despite the brain abnormalities and the onset time difference of renal abnormalities, both patients are still alive. Given the heterogeneity of the renal phenotype among GAMOS types, accurate recognition of expanding spectrum of phenotype findings and regular renal function screening are necessary for an early diagnosis and timely treatment.