La cystinurie, une pathologie lithiasique d’origine héréditaire. Enquête rétrospective chez l’enfant et l’adulte.

Abstract

Cystinuria is a rare autosomal recessive genetic disorder that alters the mechanism of reabsorption of the amino acids cystine, lysine, arginine and ornithine in the kidneys. It is caused by an abnormality in the renal and intestinal transport of cystine, which results in the formation of urinary stones and can lead to renal failure. The aim of this study was to assess the prevalence and incidence of this condition and to determine its epidemiological characteristics in children and adults in the western region of Algeria. Crystalluria analysis was performed on fresh morning urine samples to detect the presence of crystals characteristic of cystine. Morphoconstitutional analysis of the stones was carried out using a stereo microscope, followed by infrared spectrophotometry. As part of the retrospective study, we examined all the files of patients who were recruited between 2005 and 2023 at the "Urinary lithiasis" laboratory of the University of Mostaganem, affiliated to the STEVA laboratory (Faculty of Science and Technology, University of Mostaganem). The information collected included sex, age, family history, consanguinity and recurrence, as well as the composition of the stones. The prevalence of cystinuria was 1.12%, with 25 cases diagnosed among a total of 2,235 patients with urinary lithiasis. A predominance of females was observed, with a sex ratio of 0.79 (0.5 in children and 1.14 in adults). The mean age of the patients was 22 years (5 years in children, 32 years in adults) and 15% were underweight, 46% had a normal BMI, 31% were overweight and 8% were obese. The rate of consanguinity was 26% (0% in children and 33.3% in adults). 45.4% of patients had a family history of LU (28.6% and 53% respectively in children and adults), 69.6% had a history of recurrence (75% in children and 66.7% in adults). Urinary calculi were pure in 76% of cases (87.5% in children and 66.7% in adults).