ARSK-Related Mucopolysaccharidosis Type 10.

Mucopolysaccharidosis type 10 (MPS10) is a recently discovered lysosomal storage disorder caused by biallelic loss of function variants in ARSK. To date, 10 ARSK-related MPS10 patients from six families have been reported, with a median age at presentation of 9.5 years. The affected individuals usually present with progressive hip joint abnormalities. Coarse facial features, genu valgum, and joint abnormalities are variable. None demonstrated hepatosplenomegaly, neurological deficits, or cognitive impairment. Radiographically, platyspondyly, inferior tapering of the ilea with acetabular hypoplasia, irregularity of the central part of the femoral head, and metaphyseal striation of the long bones characterize this condition. Biochemical analyses reveal variable dermatan sulfate (DS) excretion in urine, with some patients showing increased DS, while others had normal urinary glycosaminoglycans (GAGs), suggesting that a normal GAG profile does not exclude this condition. This report provides a comprehensive review of existing knowledge on ARSK-related mucopolysaccharidosis.