Etude d’une maladie héréditaire monogénique: l’hyperoxalurie primitive(HOP)

Abstract

Primary hyperoxaluria (HOP) is an autosomal recessive inherited metabolic disease that is caused by a deficiency of the liver enzyme, alanine glyoxylate aminotransferase (AGT). The result is an hyperproduction and an excessive elimination of oxalate, leading to urinary stones and kidney failure. The objective of this work was to determine the prevalence of HOP and study some epidemiological parameters of this disease in patients referred to the "Urinary Lithiasis" laboratory of Mostaganem University. We consulted all the records of stone formers recruited between 2001 and 2019; there were 22 cases with HOP on a total of 1972 lithiasic patients, giving a prevalence of 1.11%. We noted: gender, age, family history of urinary lithiasis, possible consanguinity and recurrence, as well as the composition of urinary stones. The diagnosis was made by morphological analysis of the calculations using a stereomicroscope and confirmed by infrared spectrophotometer. A study of crystalluria was carried out on fresh morning urine. The average age of the patients was 39.73 years. The most affected age group was 50 to 30 years old. There was a male predominance, with a sex ratio of 2.14. The family history was found in 63.6% of stone formers and consanguinity in 18.2%. The morphological analysis of stones showed that the one that characterizes the HOP is the type Ic; it is clear, cream-coloured, its surface is smooth and budded, its section has an inorganized structure.Infrared analysis of stones revealed a characteristic whewellite spectra, with absorption peaks at 1619 cm-1, 1316cm-1 and 781 cm-1. These stones were in 45.5% of cases pure (type Ic only) and in 54.5% mixed, with a predominance of pure Ic in males. The rate of recurrence was 81.8% and was more frequent in men and subjects aged 30 to 50 years.The study of crystalluria showed very strongly polarizing crystals; that are ovoid, hematiform, their size varying from 5μm to 12.5μm, with a refractive point in the middle. These crystals were observed at a pH ranging from 5.2 to 7.8. In the absence of biomolecular technics for the diagnostic of HOP, morphological and infrared analysis of stones and the study of crystalluria remain simple and effective in this way.