HDR syndrome in a Japanese girl with biliary atresia: a case report

BACKGROUND: Hypoparathyroidism, sensorineural deafness, and renal dysplasia (HDR) syndrome is an autosomal dominant disorder. We report the first detailed case of hypoparathyroidism complicated by biliary atresia. CASE PRESENTATION: A 1-year-old Japanese girl was admitted to our hospital for living donor liver transplantation. She suffered from obstructive jaundice owing to biliary atresia. She also had persistent hypocalcemia. Despite oral calcium and abundant vitamin D supplementation, a laboratory test showed hypocalcemia (1.4 mmol/l) and hyperphosphatemia (2.6 mmol/l). The intact parathyroid hormone level was normal (66 ng/l) with severe vitamin D deficiency (25-hydroxy vitamin D: undetectable levels). There were no rachitic changes in metaphysis on X-rays. Her family history showed that her mother had sensorineural deafness, a low serum calcium level (2.1 mmol/l), hypoplastic left kidney, and a past history of an operation for right vesicoureteral reflux. We suspected that this patient and her mother have hypoparathyroidism, sensorineural deafness, and renal dysplasia syndrome. A heterozygous GATA3 gene mutation (c.736delGinsAT) was found in this patient and her mother, but not in her father. CONCLUSION: This familial case confirms the importance of family history in the diagnosis of HDR syndrome. Regardless of marked vitamin D deficiency, the complication of hypoparathyroidism prevented the onset of vitamin D deficiency rickets in our patient.