Clinical case seminar: Functional analysis of a novel GATA3 mutation in a family with the hypoparathyroidism, deafness, and renal dysplasia syndrome

The hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome is an autosomal dominant disorder caused by mutations of a member of the GATA-binding family of transcription factors, GATA3. This dual zinc finger transcription factor binds DNA with its C-terminal zinc finger (ZnF2) and stabilizes this binding with its N-terminal zinc finger (ZnF1). ZnF1 also interacts with other zinc finger proteins, notably Friend of GATA (FOG). The HDR syndrome has been described in patients with mutations affecting both ZnF1 and ZnF2 domains; the former result in inefficient interaction with FOG, and the latter result in disruption of DNA binding. We report a patient with renal failure, hypoparathyroidism, and bilateral hearing loss. Assessment of family members indicated that the disease arose as a de novo mutation in her mother. Analysis of GATA3 in the family revealed a heterozygous missense mutation resulting in a nonconservative change of a single amino acid (R276P) in the ZnF1 domain. Functional analysis using dissociation electrophoretic mobility shift and yeast two-hybrid assays showed reduced binding affinity to the GATA motifs but normal interaction with FOG in vitro. These results are consistent with the predicted functions of human GATA3-ZnF1 from three-dimensional molecular modeling and with HDR being a result of GATA3 haploinsufficiency. Copyright © 2005 by The Endocrine Society

Maintained virological suppression and renal function with reduced dose tenofovir disoproxil fumarate in renally impaired chronic hepatitis B patients

Tenofovir disoproxil fumarate (TDF) effectively suppresses viral replication in chronic hepatitis B (CHB), but occasionally leads to renal impairment. We evaluated the prevalence of viral and biochemical breakthrough and renal function kinetics in renally impaired patients with CHB on reduced and on full-dose TDF. This clinic-based longitudinal cohort study included patients receiving full and reduced dose TDF (due to eGFR [Cockcroft-Gault] 50 mL/min during dose reduction. Low dose TDF maintains renal function and viral suppression in most renally impaired patients with CHB, even in those with advanced liver disease. This useful, yet simple strategy could be particularly viable in resource-constrained settings

Genetics of vesicoureteral reflux

Primary vesicoureteral reflux (VUR) is the most common urological anomaly in children, affecting 1–2% of the pediatric population and 30–40% of children presenting with urinary tract infections (UTIs). Refluxassociated nephropathy is a major cause of childhood hypertension and chronic renal failure. The hereditary and familial nature of VUR is well recognized and several studies have reported that siblings of children with VUR have a higher incidence of reflux than the general pediatric population. Familial clustering of VUR implies that genetic factors have an important role in its pathogenesis, but no single major locus or gene for VUR has yet been identified and most researchers now acknowledge that VUR is genetically heterogeneous. Improvements in genome-scan techniques and continuously increasing knowledge of the genetic basis of VUR should help us to further understand its pathogenesis.Other funderChildren's Medical and Research Foundation6M embargo after publication - AV 8/9/2011 ke, SB-09/09/201