Collectrin gene screening in Turner syndrome patients with kidney malformation

Abstract

Turner syndrome (TS) affects one in 2500–3000 live-born girls, and is the most prevalent female sex chromosomal disorder in humans, resulting from the loss of all or part of one of the two X chromosomes (Sybert and McCauley 2004). About 50% of TS patients carry a 45, X monosomy, the rest being mosaics or structural chromosome abnormalities. TS patients’ phenotype is variable, and the wide spectrum of clinical features includes: short stature, ovarian dysgenesis, lymphedema, cardiovascular defects and renal malformation. Diabetes mellitus is also present at a rate two to four times higher than in the general population (Elsheikh et al. 2002), consistent with the finding of a relative insulin deficiency in TS on a non-immune basis, suggesting that haploinsufficiency for X-chromosome gene(s) impairs beta-cell function predisposing to diabetes mellitus in TS (Bakalov et al. 2004). The loss of the short arm of chromosome X (Xp), common to all TS, generally results in the full syndrome phenotype (Elsheikh et al. 2002). So far, a correlation between karyotype and phenotype in TS patients has not been clearly defined. Haploinsufficiency of several genes mapped to the short arm of X chromosome has been related to the clinical signs observed in TS patients; for example, the SHOX (short stature homeobox-containing gene) responsible for the short stature characteristic of the patients. Association of renal abnormalities and TS varies from 33% to 70% (Matthies et al. 1971). These include horseshoe kidney, duplication of collecting system, ectopic kidney, ureteropelvic stenosis, renal agenesis and renal cysts. Two forms of cystic kidney disease have been described in