Early diagnosis and follow-up of cerebrotendinous xanthomatosis in infant siblings presenting with congenital diarrhea: A case study from Saudi Arabia.

Cerebrotendinous xanthomatosis (CTX) is a rare autosomal recessive neurometabolic genetic disease resulting from defects in the bile acid metabolism. This report describes cases diagnosed with CTX at an exceptionally early age - 4 months (Patient #2 and #3) - making them the youngest reported cases to date. All three presented with intractable congenital diarrhea, a hallmark manifestation of the disease. The diagnosis was confirmed through metabolic bile acids analysis in urine and genetic testing. The siblings were treated with Chenodeoxycholic acid (15 mg/kg/day) during the first year of treatment, resulting in an improvement in diarrhea in all three. However, cognitive function remained unimproved in one patient. Additionally, the presence of dysmorphic features, observed in these patients, have not been documented in previous CTX cases. The diagnosis prompted solely by the persistent diarrhea, highlights a critical, under-recognized early manifestation. These findings underscore the importance of raising awareness among physicians to enable early diagnosis and timely treatment, which may prevent disease progression.