Thyroid hypoplasia as a cause of congenital hypothyroidism in monozygotic twins concordant for Rubinstein-Taybi syndrome.
Bottom Line: Thyroid function tests in the first twin revealed the following results: free thyroxine (T4) 8.4 pg/mL, thyrotropin (TSH) 4.62 mIU/L, thyroglobulin (TG) 213.24 ng/mL and a normal level of urinary iodine excretion (UIE).Thyroid function test results in the second twin in the second week were: free T4 5.9 pg/mL, TSH 9.02 mIU/L, TG 204.87 ng/mL, and normal UIE levels.The rarity of cases of twins with RSTS (concordant) co-existing with CH led us to present this report.
Affiliation: Erciyes University, Faculty of Medicine, Department of Pediatrics, Division of Neonatology, Kayseri, Turkey.Show MeSH
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Mentions: Laboratory findings including hemoglobin, hematocrit, serum calcium, phosphorus, alkaline phosphatase, BUN, creatinine, electrolytes, blood sugar, ALT, AST, acid-base values, and urine analysis were normal. Both twins had the same blood group [A Rh (-)], consistent with monozygocyty. Thyroid function test results on day 7 in the first twin were: free thyroxine (T4) 8.4 pg/mL (normal: 11±3 pg/mL), thyrotropin (TSH) 4.62 mIU/L (normal: 3.8±2.3 mU/L), thyroglobulin (TG) 213.24 ng/mL (normal: up to 250 ng/mL) with normal level of urinary iodine excretion (UIE) 30 mg/dL (normal: higher than 10 mg/dL). At age two weeks, thyroid function test results in the second twin were: free T4 5.9 pg/mL (normal: 12±3 pg/mL), TSH 9.02 mIU/L (normal: 4.3±1.6 mU/L), TG 204.87 ng/mL (normal: up to 250 ng/mL), and UIE 40 mg/dL. Thyroid volumes were 0.36 mL and 0.31 mL (0.60±0.07 mL) (11), respectively (Table 1). TH was confirmed by technetium 99 m pertechnetate thyroid scans, and no ectopic tissue was observed in either twin (Figure 2).
Affiliation: Erciyes University, Faculty of Medicine, Department of Pediatrics, Division of Neonatology, Kayseri, Turkey.