Clinical Auditory Phenotypes Associated with GATA3 Gene Mutations in Familial Hypoparathyroidism-deafness-renal Dysplasia Syndrome

Hypoparathyroidism, deafness and renal dysplasia syndrome caused by a GATA3 splice site mutation leading to the activation of a cryptic splice site

The HDR syndrome is a rare autosomal dominant disorder characterised by Hypoparathyroidism, Deafness, and Renal dysplasia, and is caused by inactivating heterozygous germline mutations in the GATA3 gene. We report an 11-year-old girl with HDR syndrome caused by a heterozygous mutation located at the splice acceptor site of exon 5 of the GATA3 gene (NM_001002295.2: c.925-1G>T). Functional studies using a minigene assay showed that this splice site mutation abolished the normal splicing of the GATA3 pre-mRNA and led to the use of a cryptic splice acceptor site, resulting in the loss of the first seven nucleotides (TCTGCAG) of exon 5 in the GATA3 mRNA. These findings increase the understanding of the mechanisms by which GATA3 splicing mutations can cause HDR syndrome.

Hypoparathyroidism, deafness, and renal dysplasia syndrome: 20 Years after the identification of the first GATA3 mutations

The hypoparathyroidism, deafness, and renal dysplasia (HDR) syndrome is an autosomal dominant disorder caused by heterozygous mutations of the GATA3 gene. In the last 20 years, since the identification of the genetic cause of the HDR syndrome, GATA3 mutations have been reported in 124 families (177 patients). The clinical aspects and molecular genetics of the HDR syndrome are reviewed here together with the reported mutations and phenotypes. Reported mutations consist of 40% frameshift deletions or insertions, 23% missense mutations, 14% nonsense mutations, 6% splice-site mutations, 1% in-frame deletions or insertions, 15% whole-gene deletions, and 1% whole-gene duplication. Missense mutations were found to cluster in the regions encoding the two GATA3 zinc-finger domains. Patients showed great clinical variability and the penetrance of each HDR defect increased with age. The most frequently observed abnormality was deafness (93%), followed by hypoparathyroidism (87%) and renal defects (61%). The mean age of diagnosis of HDR was 15.3, 7.5, and 14.0 years, respectively. However, patients with whole-gene deletions and protein-truncating mutations were diagnosed earlier than patients with missense mutations.

GATA3 rs3824662 gene polymorphism as possible risk factor for systemic lupus erythematosus

Background

There is no report about the association between GATA3 rs3824662 polymorphism and systemic lupus erythematosus (SLE).

Objective

To investigate the possible role of GATA3 rs3824662 polymorphism as a susceptibility risk factor for either adult SLE (aSLE) or pediatric SLE (pSLE) and to evaluate its role in the development of lupus nephritis (LN) in pSLE.

Methods

Typing of GATA3 rs3824662 polymorphism was done using real-time polymerase chain reaction for three groups; 104 pSLE patients, 140 aSLE patients and 436 age- and sex-matched healthy controls.

Results

Non-significant differences were found between SLE patients and healthy controls for the allele and genotype frequencies of GATA3 rs3824662 ( p > 0.05). In pSLE; the AC genotype was associated with LN ( p = 0.04); the A allele and AC genotype were associated with persistent proteinuria ( p = 0.036 and 0.01, respectively) and both the A allele and AA genotype were associated with higher chronicity index ( p = 0.031 and 0.04, respectively). In aSLE; the C allele was associated with cellular cast ( p = 0.03) and thrombocytopenia ( p = 0.01). Logistic regression analysis revealed significant association between the AC+AA genotypes and the prediction of LN and renal active disease in pSLE ( p = 0.04 and 0.01, respectively).

Conclusion

GATA3 rs3824662 is not associated with susceptibility to SLE either in adult or in pediatric patients; however, in pSLE patients, the heterozygous AC genotype could be considered a risk factor for LN. At the same time, the AC and AA genotypes could be considered as predictors for LN and active renal disease. However, the small sample size is a limiting factor of the present study when interpreting the positive association.