[Biochemical and molecular diagnosis of primary hyperoxaluria type 1: Tunisian study about 15 cases].

[primary hyperoxaluria type 1]

The primary type 1 hyperoxaluria (HP 1 ) is the most frequent and severe form of the primary hyperoxaluriae . It is related to an enzymatic deficit in alanine glyoxylate aminotransferase (AGT ). It is a recessive autosomic disease . Rare in Europe , it is responsible for 13 % of the end stage renal failure in the Tunisian child .The aim of this work is to evaluate the biological and molecular examinations contributing with the early diagnosis and the follow-up of the HP 1 patients and to test their response to pyridoxin .A prospective study of 15 children who have oxaluria lower than 500 μmol /l and normal renal function is carried out . The cristalluria study , oxaluria and the glycolate-glycerate urinary ratio were carried out on all the patients . The so -called mutation maghrebean T 853 (Ile 244 Thr ) was detected by direct sequencing of the exon 7 gene AGXT . The response to pyridoxin was tested among 13 patients .The oxaluria concentration was greater or equal to 1000 μmol /l in nine cases (60 %) and ranging between 600 and 1000 μmol /l in the remaining cases . The oxaluria flow was significantly high depending on the age . The glycolaturia was high among eight patients (57 %). In 61 ,5 % of the cases , the most frequent crystalline species was whewellite (C 1 ). The "maghrebin " mutation was identified in nine patients at the heterozygous state , showing 25 % allelic frequency . The response to pyridoxin was observed in the 13 tested cases .The HP 1 is frequent in our country from where the need for an early diagnosis . The use of simple biochemical tools such as the study of the cristalluria , the morphological analysis of stones and the oxaluria allow to direct the diagnosis towards a HP 1 , confirmed by the glycolaturia determination . The molecular biology is required in the atypical forms .