Severe growth retardation in Dent disease: a case report of a novel OCRL variant.

INTRODUCTION: Dent disease type 2 (DD-2) is a rare X-linked recessive renal tubulopathy caused by mutations in the OCRL gene. Clinically it is characterised by low molecular weight proteinuria (LMWP), hypercalciuria, and nephrocalcinosis. The phenotypic spectrum of DD-2 is expanding with the identification of new pathogenic variants.

CASE REPORT: A 12-year-old male presenting with marked short stature and poor weight gain was found to have LMWP, haematuria, hypercalciuria, and bilateral nephrocalcinosis on initial clinical evaluation. Renal function was normal. There was no relevant family history. Genetic analysis revealed a hemizygous missense variant (c.899 C > A; p.Ala300Asp) in the OCRL gene, which has not been previously reported in the literature. No abnormalities were found on ocular or neurological examination as the same gene also causes Lowe syndrome. Therefore DD-2 was considered in this patient. Hydrochlorothiazide treatment was initiated but discontinued due to hypokalaemia. Growth hormone therapy was started by the endocrinology clinic due to severe growth retardation.

CONCLUSION: Dent disease can present with a wide range of clinical findings. This case report describes a novel OCRL gene variant associated with DD-2. This newly identified variant contributes to the genotypic and phenotypic diversity of the disease, however, without functional validation, it is difficult to determine whether growth retardation is a significant complication in DD-2. Early diagnosis and a multidisciplinary approach are crucial for improving long-term outcomes.