Monogenic urinary lithiasisin Tunisian children: 25 years’ experience of a referral center

Aim: To describe the clinical, biochemical and evolutive profile of monogenic urinary lithiasis in Tunisian children followed up in a reference service, during a 25 years period. Methods: This was a single-center retrospective observational study of children with urolithiasis, conducted in the pediatric nephrology department in Charles Nicolle Hospital, Tunis, Tunisia over 25 years (January 1(st), 1996 to December 31, 2020). Children≤18 of age with urolithiasis with or without nephrocalcinosis related to a monogenic disease were included in our study. Results: A total of 66 children were included in our study. Patients were 5.92±3.48 years of age at the time of urolithiasis diagnosis, and 5.33±3.66 years of age at the time of the underlying pathology diagnosis. The inherited urolithiasis disorders found in our series were: primary hyperoxaluria in 44 cases, cystinuria in 9 cases, Lesch Nyhan syndrome in 5 cases. Renal tubular acidosis was found in 3 cases, and hereditary xanthinuria in 2 cases. Bartter syndrome, adenine phosphoribosyltransferase deficiency and Hereditary hypophosphatemic rickets with hypercalciuria were found in 1 case each. After an average follow-up of 6.45±3.79 years, six patients were in end-stage renal disease. Three patients had died, all of them being followed for primary hyperoxaluria type 1. Conclusions: Monogenic urinary lithiasis, although rare, are most likely under-diagnosed in countries with high consanguinity such as Tunisia. The screening of these diseases seems to be of primary importance because of their significant morbidity.