SAT-065 A Novel De Novo GATA3 Gene Mutation in an Adolescent with HDR Syndrome

Abstract Background: GATA3 encodes a transcription factor critical for embryonic development of the parathyroid glands, kidney, inner ear, thymus, and the central nervous system. Heterozygous loss-of-function mutations in GATA3 are associated with hypoparathyroidism, sensorineural deafness and renal disease (HDR syndrome). Clinical Case: A 12 yo male with left hip pain underwent a closed reduction for left slipped capital femoral epiphysis. The pre-op evaluation revealed hypocalcemia (serum Ca 7.7 mg/dL; nl: 8.8-10.2), creatinine 0.46 mg/dL (0.5-1.0), TSH 3.16 uU/mL (0.3-4.2), FT4 1.36 ng/dL (0.8-1.8). Oral calcium and vitamin D supplementation was begun, and 2 wks later, follow-up evaluation revealed serum Ca of 9.4 mg/dL, intact PTH 4.6 pg/mL (10-69), phosphorus 5.9 mg/dL (3.3-5.3), 25-OHD 26 ng/mL (30-100), and a normal chromosomal microarray. Bone density (DXA) Z-scores for hip and spine were -1.7 and 0.8, respectively. At age 13 he underwent bilateral osteotomy due to bilateral hip dysplasia and removal of hardware the next year. At age 15 he underwent left total hip replacement for avascular necrosis. In the post-operative period hypocalcemia recurred (5.9-6.7mg/dL), and he was referred for endocrine evaluation. He was of mixed African American and Puerto-Rican descent. He had difficulties in school and required eyeglasses and hearing aids. Past history included congenital scoliosis (right T11-12 rib fusion, wedged L1 vertebra, and incomplete fusion of posterior elements of L4 and L5), a small right kidney (per ultrasound examination), bilateral orchiopexy for undescended testicles (age 2), diagnoses of ADHD (at age 5); sensorineural hearing loss and psoriasis (age 12), and gastroesophageal reflux (age13). Multiple paternal family members were reported to have abnormal calcium levels and hearing/vision problems, but no known diagnosis. On exam, he had no facial dysmorphism, but left supernumerary nipples, lumbar lordosis and thoracic kyphosis, and clinodactyly. He had achieved Tanner 5 secondary sexual characteristics. There was no Chvostek’s sign. Laboratory investigation revealed Ca 7.9 mg/dL, phosphorus 5.9 mg/dL (3.1-4.7), alkaline phosphatase 123 U/L (50-380), 25-OHD 32 ng/mL, intact PTH 10.2 pg/mL. Treatment with calcium carbonate and calcitriol was begun. Whole exome sequencing identified a heterozygous mutation in GATA3 (c.1061C>T, p.Pro354Leu), predicted to be damaging. This variant has not been reported in literature or public database to our knowledge. Conclusion: This case highlights the importance of genetic testing in the setting of unexplained hypoparathyroidism, and identifies a likely novel mutation in GATA3, providing a basis to counsel the family and encourage medical follow up of suspected family members. References: Barakat, A., et al., Familial nephrosis, nerve deafness, and hypoparathyroidism. J Pediatr 91:61-64, 1977