Renal phenotypic variability in HDR syndrome: glomerular nephropathy as a novel finding

HDR syndrome (hypoparathyroidism, sensorineural deafness, renal abnormalities) (OMIM #146265) is a rare autosomal dominant disorder caused by mutations in the GATA-3 gene (OMIM 13120), a transcription factor coding for a protein involved in vertebrate embryonic development. More than a hundred cases with variable renal features have been described so far. Here, we report on a patient suffering from HDR syndrome with glomerular nephropathy. Hypoparathyroidism appeared early in childhood but the subsequent features of HDR occurred later in the form of bilateral sensorineural deafness and renal insufficiency associated with nephrocalcinosis. HDR was not initially diagnosed due to the appearance of a transitory cardiac involvement and atypical renal symptoms (diffuse proliferative glomerulonephritis characterized by a self-limiting nephrotic syndrome). Conclusion: HDR syndrome with glomerular nephropathy has not yet been reported to our knowledge. Further studies of GATA-3 are needed to explore the involvement of this transcription factor in the development of HDR in humans, particularly in the kidneys.