LAUSR

The retinitis pigmentosa GTPase regulator interacting protein 1-like gene (RPGRIP1L) encodes a ciliary protein essential for basic embryonic development. Biallelic variants of RPGRIP1L cause Joubert syndrome (JS) with renal defects. In addition to characteristic JS features (cerebellar and brain stem malformations, developmental delays, hypotonia, irregular breathing patterns, eye movement abnormalities, ataxia, and intellectual disability), affected individuals typically also exhibit renal disorders, such as cystic kidney disease and nephronophthisis. Here, we describe a 10-year-old female of Chinese descent who was referred to hospital due to lower limb arthralgia. However, the presence of short stature, facial deformities, renal abnormalities, and renal failure suggested a diagnosis of congenital syndrome disorder. Whole-exome sequencing (WES) revealed that the patient was homozygous for a previously unreported RPGRIP1L variant featuring a missense mutation (NM_015272; c.2180G>A, p.Gly727Asp). A subsequent cranial MRI confirmed the presence of midbrain molar tooth sign and cerebellar Dandy-Walker malformation. However, no significant developmental delays or neurological abnormalities were noted. This study makes a significant contribution to the literature by expanding knowledge of the JS-causing RPGRIP1L variant spectrum, enhancing understanding of RPGRIP1L variant-associated JS phenotypes.