Vitamin D deficiency in a patient with HDR syndrome

Case report: Hypoparathyroidism-sensorineural hearing loss-renal dysplasia without febrile seizures: a novel mutation in the GATA3 gene

Objective

This study aims to summarize the diagnostic and treatment experience of a case of Hypoparathyroidism-Sensorineural Hearing Loss-Renal Dysplasia (HDR) syndrome caused by a heterozygous mutation in the GATA3 gene.

Methods

The diagnostic and treatment process of the patient with HDR syndrome in our hospital was compared and analyzed.

Results

A 9-month-old male infant with a history of poor physical condition and increased susceptibility to infections. At the age of 2 months, ptosis was observed in the left eye. Laboratory tests revealed decreased serum calcium, elevated blood phosphorus levels, and reduced parathyroid hormone (PTH) levels, indicating the presence of "Hypoparathyroidism". Genetic testing identified a heterozygous mutation in the GATA3 gene in the patient, specifically a nucleotide change from G to T at position 800 (c.800G>T). This mutation resulted in the substitution of cysteine with phenylalanine at amino acid position 267 (p.C267F). The missense mutation was determined to be both pathogenic and novel.

Conclusion

Early genetic testing should be prioritized, and regular monitoring of kidney development and hearing status is essential. The reported case, featuring the novel GATA3 gene mutation c.800G>T (p.C267F), contributes to the enrichment of the genetic database.

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.