Etude d’une maladie génétique : le syndrome de Lesch-Nyhan/ /

Abstract

Lesch-Nyhan syndrome (LNS) is an X-linked recessive disorder affecting purine metabolism. It is caused by a mutation in the HPRT1 gene, located on the X chromosome in region Xq26. This mutation results in a partial or total deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). Lesch-Nyhan variants are classified into three clinical phenotypes: Lesch-Nyhan disease (LND), characterised by neurological symptoms, self-mutilating behaviour and hyperuricemia; the second is HGPRT-related neurological disorder (HND), which presents a variable degree of neurological symptoms and hyperuricemia. Finally, the third variant, HGPRT-related hyperuricaemia (HRH) manifests as hyperuricaemia and its consequences. These conditions can lead to complications such as gout and the formation of urinary (uric acid) crystals and stones. There are biochemical methods of diagnosis, which we investigated in this work. These include determination of urinary and serum uric acid levels, as well as identification of the type of stone (composed of uric acid in the case of LNS) using morpho-constitutional analysis to determine the type and composition using infrared spectroscopy. Finally, analysis of crystalluria (an intermediate stage in lithogenesis), which enables urinary crystals to be observed, is crucial in predicting stone formation and preventing recurrence. The prevalence of this disease is very low. We found no cases of LNS in the regions of Mostaganem and Oran, but it should be remembered that our survey was not exhaustive. It is crucial that these results be verified by further, more in-depth studies. It would be relevant to create a national register to document cases of LNS in Algeria, in order to monitor prevalence and plan healthcare.