Idiophatic hypercalciuria: familial study

Abstract

The clinical and epidemiological importance of studies on idiopathic hypercalciuria (HcaU) occurs in about 50% of the carrying patients of lithiasis urinary, being this last estimated in 12% of the population in the western countries. The objective of this work is to contribute for the study of the hypercalciuria (HcaU) in our way, mainly regarding the family evaluation, inheritance pattern, clinical expressivity and comparison with the literature data. The families of nine probing carriers of HcaU were studied prospectively from July-1998 to May-2000. Through interviews family pedigrees were built for the evaluation of the transmission pattern and clinical expressivities. The excretion of calcium and the presence of symptoms and signs of the illness especially those related to the lithiasis and the hematuria were also evaluated. Nine probing carriers were submitted to the study, along with 55 close family individuals (calcium excretion and clinical expressivity) and 255 distant relatives (expressivity). The mains characteristics of the carriers were: female/male 6/9; average age 33,6 years; signs and/or symptoms of lithiasis 8/9 and hematuria 2/9. All the individuals presented normal calcemia and an average urinary excretion of calcium of 5,9 ± 1,49mg/kg/day. The manifestations of disease observed in close relatives was 52,7%, about five times greater than average. The analysis of the family pedigrees supports the assertive that the illness has autossomic dominant transmission: the symptoms were present in 52,7% of the individuals, affecting several individuals in successive generations, transmission of individuals from both sexes for male and female individuals of the family. A clinical expressivity was variable. Idiopathic hypercalciuria presented a pattern of dominant autossomic inheritance, with prevalence of 52,7% between the relatives and variable clinical expressivity. The data observed in our study are similar to the observed in the world literature