Hypoparathyroidism, sensorineural deafness, and renal dysgenesis syndrome with a GATA3 mutation

Ocular manifestations of congenital anomalies of the kidney and urinary tract (CAKUT)

Congenital anomalies of the kidney and urinary tract (CAKUT) are among the most common birth defects worldwide and a major cause of kidney failure in children. Extra-renal manifestations are also common. This study reviewed diseases associated with the Genomics England CAKUT-associated gene panel for ocular anomalies. In addition, each gene was examined for expression in the human retina and an ocular phenotype in mouse models using the Human Protein Atlas and Mouse Genome Informatics databases, respectively. Thirty-four (54%) of the 63 CAKUT-associated genes (55 'green' and 8 'amber') had a reported ocular phenotype. Five of the 6 most common CAKUT-associated genes (PAX2, EYA1, SALL1, GATA3, PBX1) that represent 30% of all diagnoses had ocular features. The ocular abnormalities found with most CAKUT-associated genes and with five of the six commonest were coloboma, microphthalmia, optic disc anomalies, refraction errors (astigmatism, myopia, and hypermetropia), and cataract. Seven of the CAKUT-associated genes studied (11%) had no reported ocular features but were expressed in the human retina or had an ocular phenotype in a mouse model, which suggested further possibly-unrecognised abnormalities. About one third of CAKUT-associated genes (18, 29%) had no ocular associations and were not expressed in the retina, and the corresponding mouse models had no ocular phenotype. Ocular abnormalities in individuals with CAKUT suggest a genetic basis for the disease and sometimes indicate the affected gene. Individuals with CAKUT often have ocular abnormalities and may require an ophthalmic review, monitoring, and treatment to preserve vision.

Hypoparathyroidism, Sensorineural Deafness, and Renal Disease Syndrome Presenting With Febrile Seizures and Hypocalcemia

HDR syndrome is a rare genetic disorder caused by mutations in the GATA3 gene and characterized by hypoparathyroidism, sensorineural deafness, and renal disease. Here, we report case of a 9-month-old male with history of hydronephrosis and sensorineural deafness who presented with febrile seizures. He was found to have hypocalcemia and inappropriately normal parathyroid hormone. His neurologic and infectious workup were negative. Genetic testing revealed a nonsense mutation in the GATA3 gene, consistent with HDR syndrome. Hypocalcemia was responsive to calcium carbonate and calcitriol treatment. This case highlights hypocalcemia caused by hypoparathyroidism as a potential etiology of seizures. When hypoparathyroidism is detected with either hearing loss or renal disease, HDR syndrome should be considered, and other features of the syndrome should be investigated.

Suppression of GATA-3 increases adipogenesis, reduces inflammation and improves insulin sensitivity in 3T3L-1 preadipocytes

Impaired adipogenesis plays an important role in the development of obesity-associated insulin resistance and type 2 diabetes. Adipose tissue inflammation is a crucial mediator of this process. GATA-3 plays important roles in adipogenesis and inflammation. The aim of this study is to investigate the impact of GATA-3 suppression on improving adipogenesis, lowering inflammation and reversing insulin resistance. GATA-3 levels were measured in subcutaneous (SC) and omental (OM) adipose tissues obtained from insulin sensitive (IS) and insulin resistant (IR) obese individuals during weight reduction surgeries. The effect of GATA-3 suppression on adipogenesis, expression of inflammatory cytokines and insulin resistance biomarkers was performed in 3T3L-1 mouse preadipocytes via transfection with GATA-3-specific DNAzyme. GATA-3 expression was higher in OM compared to SC adipose tissues and in stromal vascular fraction-derived differentiating preadipocytes from IR obese individuals compared to their IS counterparts. Suppression of GATA-3 expression in 3T3L-1 mouse preadipocytes with GATA-3 specific inhibitor reversed 4-hydroxynonenal-induced impaired adipogenesis and triggered changes in the expression of insulin signaling-related genes. GATA-3 inhibition also modulated the expression of IL-6 and IL-10 and lowered the expression of insulin resistance biomarkers (PAI-1 and resistin) and insulin resistance phosphoproteins (p-BAD, p-PTEN and p-GSK3β). Inhibiting GATA-3 improves adipocytes differentiation, modulates the secretion of inflammatory cytokines and improves insulin sensitivity in insulin resistant cells. Suppression of GATA-3 could be a promising tool to improve adipogenesis, restore insulin sensitivity and lower obesity-associated inflammation in insulin resistant individuals.

Hypoparathyroidism, Sensorineural deafness and renal disease (Barakat syndrome) caused by a reduced gene dosage in GATA3: a case report and review of literature

BACKGROUND

Barakat syndrome is an autosomal dominant rare genetic disease caused by haploinsufficiency of the GATA binding protein 3 (GATA3) gene. It is also known as HDR syndrome, and is characterized by varying degrees of hypoparathyroidism, sensorineural deafness and renal disease. This is the first report of a heterozygous GATA3 whole gene deletion causing HDR syndrome in a Sri Lankan family.

CASE PRESENTATION

A 13-year-old boy with an acute febrile illness, hypocalcaemia and bilateral carpopedal spasm was referred for evaluation. A past medical history of treatment for persistent hypocalcaemic symptoms since the age of 7 months was obtained. Biochemical investigations showed persistent low serum corrected calcium levels with hyperphosphataemia, hypomagnesaemia, low parathyroid hormone levels, hypercalciuria, and low total 25-hydroxy vitamin D levels. His renal functions and renal sonography were normal. Audiometry showed bilateral moderate to severe sensorineural hearing loss. On screening, his mother was also found to have asymptomatic hypocalcaemia, hypomagnesaemia, hyperphosphataemia, hypercalciuria and low total 25-hydroxy vitamin D levels. She had impaired renal functions and chronic parenchymal changes in the renal scan. Audiometry showed bilateral profound sensorineural hearing loss. Genetic analysis using multiplex-ligation dependent probe amplification showed a reduced gene dosage for GATA3 that is consistent with a heterozygous whole gene deletion in both the child and mother.

CONCLUSIONS

This report demonstrates the wide intra-familial phenotypic variability observed in HDR syndrome and adds further to the existing scientific literature on the genotype-phenotype correlation of this syndrome. It highlights the need for HDR syndrome to be considered in the differential diagnosis of persistent hypocalcaemia with sensorineural deafness and/or renal involvement, and for appropriate genetic evaluation to be done to confirm the diagnosis.

Barakat syndrome revisited

Barakat syndrome also known as HDR syndrome (Online Mendelian Inheritance in Man [OMIM] 146255), was first described by Barakat et al. in . It is a rare genetic disorder characterized by the triad of hypoparathyroidism "H," sensorineural deafness "D," and renal disease "R." The defect is caused by deletions in chromosome 10p14 or mutations in the GATA3 gene. Although the syndrome has been phenotypically defined by this triad the literature identifies cases with different components with, or without GATA3 defects making the definition of the syndrome confusing. We analyzed 180 cases and attempted to define the phenotype of the syndrome and suggest guidelines for diagnosis. We suggest that the diagnosis could be confirmed in patients who have all three components, and in those who have two components with a positive family history. GATA3 testing is optional to establish the diagnosis in these patients. The syndrome should be considered in patients with isolated "D" where other causes of "D" have been excluded and those with isolated "R," especially if there is family history of any of these components. In these instances, confirmatory GATA3 testing is indicated to confirm the diagnosis. In patients with nonsurgical "H," where "D" and "R" have been conclusively ruled out GATA3 studies are not needed as none of these patients were shown to be GATA3 haploinsufficient. Only 64.4% of patients in our review had "HDR." Some findings might have not been recognized or may could have appeared later in life, but it is evident that this syndrome is genotypically heterogeneous.

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

Background:

Hypoparathyroidism-deafness-renal dysplasia (HDR) syndrome is an autosomal dominant disorder primarily caused by haploinsufficiency of GATA binding protein 3 (GATA3) gene mutations, and hearing loss is the most frequent phenotypic feature. This study aimed at identifying the causative gene mutation for a three-generation Chinese family with HDR syndrome and analyzing auditory phenotypes in all familial HDR syndrome cases.

Methods:

Three affected family members underwent otologic examinations, biochemistry tests, and other clinical evaluations. Targeted genes capture combining next-generation sequencing was performed within the family. Sanger sequencing was used to confirm the causative mutation. The auditory phenotypes of all reported familial HDR syndrome cases analyzed were provided.

Results:

In Chinese family 7121, a heterozygous nonsense mutation c.826C>T (p.R276*) was identified in GATA3. All the three affected members suffered from sensorineural deafness and hypocalcemia; however, renal dysplasia only appeared in the youngest patient. Furthermore, an overview of thirty HDR syndrome families with corresponding GATA3 mutations revealed that hearing impairment occurred earlier in the younger generation in at least nine familial cases (30%) and two thirds of them were found to carry premature stop mutations.

Conclusions:

This study highlights the phenotypic heterogeneity of HDR and points to a possible genetic anticipation in patients with HDR, which needs to be further investigated.

A Mendelian randomization study of the effect of calcium on coronary artery disease, myocardial infarction and their risk factors

Meta-analyses of randomized controlled trials (RCTs) suggest calcium could have adverse effects on cardiovascular disease, although these findings are controversial. To clarify, we assessed whether people with genetically higher calcium had a higher risk of coronary artery disease (CAD), myocardial infarction (MI) and their risk factors. We used a two-sample Mendelian randomization study. We identified genetic variants (single nucleotide polymorphisms (SNPs)) that independently contributed to serum calcium at genome-wide significance which we applied to large extensively genotyped studies of CAD, MI, diabetes, lipids, glycaemic traits and adiposity to obtain unconfounded estimates, with body mass index (BMI) as a control outcome. Based on 4 SNPs each 1 mg/dl increase in calcium was positively associated with CAD (odds ratio (OR) 1.49, 95% confidence interval (CI) 1.02–2.17), MI (OR 1.58, 95% CI 1.06–2.35), LDL-cholesterol (0.21 standard deviations, 95% CI 0.01–0.4), total cholesterol (0.21 standard deviations, 95% CI 0.03-0.38) and possibly triglycerides (0.19 standard deviations, 95% CI −0.1–0.48), but was unlikely related to BMI although the estimate lacked precision. Sensitivity analysis using 13 SNPs showed a higher risk for CAD (OR 1.87, 95% CI 1.14–3.08). Our findings, largely consistent with the experimental evidence, suggest higher serum calcium may increase the risk of CAD.

Frequency of Congenital Heart Diseases in Prelingual Sensory-Neural Deaf Children

INTRODUCTION

Hearing impairment is the most frequent sensorial congenital defect in newborns and has increased to 2-4 cases per 1,000 live births. Sensory-neural hearing loss (SNHL) accounts for more than 90% of all hearing loss. This disorder is associated with other congenital disorders such as renal, skeletal, ocular, and cardiac disorders. Given that congenital heart diseases are life-threatening, we decided to study the frequency of congenital heart diseases in children with congenital sensory-neural deafness.

MATERIALS AND METHODS

All children who had undergone cochlear implantation surgery due to SNHL and who had attended our hospital for speech therapy during 2008-2011 were evaluated by Doppler echocardiography.

RESULTS

Thirty-one children (15 boys and 16 girls) with a mean age of 55.70 months were examined, and underwent electrocardiography (ECG) and echocardiography. None of the children had any signs of heart problems in their medical records. Most of their heart examinations were normal, one patient had expiratory wheeze, four (12%) had mid-systolic click, and four (12%) had an intensified S1 sound. In echocardiography, 15 children (46%) had mitral valve prolapse (MVP) and two (6%) had minimal mitral regurgitation (MR). Mean ejection fraction (EF) was 69% and the mean fractional shortening (FS) was 38%.

CONCLUSION

This study indicates the need for echocardiography and heart examinations in children with SNHL.