ESPE Abstracts

Introduction: CHARGE syndrome is characterized with coloboma, heart defects, atresia of choanae, retardation of growth and development, genital hypoplasia and ear abnomalities. Recently, symptoms of CHARGE syndrome and 22q11.2 deletion syndrome were known to overlap. We describe a case of CHARGE syndrome that has variation in the CHD7 gene with hypoparathyroidism.

Case Report: The patient is an 11-year-old boy who was born at 39 weeks and 4 days gestational age and 2700 g birth weight. Cardiac malformation was noticed during fetus. Immediately after birth, he was intubated and respiratory management was started. He showed hypocalcemia during the neonatal period and was started with alfacalcidol for a while. At 17 days of age, aortic transection and ventricular septal defect were oparated. Tracheostomy was performed due to the difficulty of extubation at one month of age. The CHD7 variat was identified as c.934C>T at 2 years of age and he was referred to our hospital thereafter due to moving. At 5 years of age, we performed blood tests for short stature. Calcium was 8.2 mg/dl, Phosphorus was 6.7 mg/dl, alkaline phosphatase (IFCC) was 222 U/l, intact–PTH was 9 pg/ml (reference range: 10–65 pg/mL) and albumin was 4.3 mg/dL. Blood tests including calcium were not performed in previous hospital. He was diagnosed with primary hypoparathyroidism and were stateted with alfacalcidol (0.02 µg/kg/day) was started. Thereafter, calcium remains stable between 7.2 and 9.4 mg/dl, and intact–PTH also remains at lower levels. Fortunately, no hypocalmica-induced convulsions were observed. There was no 22q11.2 deletion in the FISH assay.

Discussion: Both alleles of CHD7, the gene responsible for CHARGE syndrome, and TBX1, the gene responsible for 22q11.2 deletion syndrome, are required for normal development of the fourth gill artery. These genetic dysfunctions are known to induce following hypoparathyroidism and hypocalcemia. There has been a high degree of overlap in the clinical presentation of CHARGE syndrome and 22q11.2 syndrome. Hypoparathyroidism has been reported to occur in 72% of patients with CHARGE syndrome, more frequently than with 22q11.2 deletion syndrome. In contrast, hypoparathyroidism has been reported to occur in 37.5% of patients with CHARGE syndrome and 60% of patients with 22q11.2 deletion syndrome. Both pediatric endocrinologists and pediatrician/neonatologists involved in CHARGE syndrome need to be aware of complications of hypoparathyroidism.

Conclusion: Caution is warranted that hypoparathyroidism may occur in CHARGE syndrome.