Thyroid abnormalities by ultrasonography in neonates with congenital hypothyroidism.

OBJECTIVES: To investigate the usefulness of thyroid ultrasonography for neonates with congenital hypothyroidism. Study design Patients (n=66) were evaluated by ultrasonography at age 15.2+/-12 days. RESULTS: Thyroid scanning was more sensitive for the identification of ectopic tissue as ultrasonography showed ectopic thyroid tissue in only 9 of 42 cases. In cases for which no iodine uptake was demonstrated by thyroid scanning (n=12), ultrasonography showed normally located thyroid tissue in 2 patients. Therefore, on the basis of both thyroid scanning and ultrasonography, 10 cases were classified as athyreosis, and 14 cases were classified as showing normal location of the thyroid gland. Among the latter 14 cases, 5 showed a developmental abnormality. Ultrasonography also revealed additional phenotypic abnormalities in patients with thyroid dysgenesis, with cysts (n=6) and thymus tissue (n=4) within the empty thyroid area, which are novel observations in these patients. CONCLUSIONS: Ultrasonography may reveal additional findings with regard to those obtained by scintigraphy such as information regarding the anatomy of the thyroid gland, presence of cysts, and presence of additional thymic tissue within the empty thyroid area.

Neonatal diabetes mellitus: chromosomal analysis in transient and permanent cases.

OBJECTIVES: To describe a large cohort of patients with transient neonatal diabetes mellitus (TNDM) and permanent neonatal diabetes mellitus (PNDM), and to investigate whether chromosome 6 analysis helps to distinguish TNDM from PNDM. STUDY DESIGN: Patients with TNDM (n = 29) (insulin therapy for <3 years) and 21 with PNDM were identified through a nationwide study. RESULTS: Although patients with PNDM were less likely to have had intrauterine growth restriction (36% vs 74% for TNDM, P <.006), were older at diagnosis (median: 27 vs 6 days, P <.01), and had higher initial insulin requirements (1.4 U/kg/day vs 0.6 U/kg/day, P <.006), no clinical features were reliable in distinguishing PNDM from TNDM on an individual case basis. Permanent insulin-dependent diabetes developed in 5 TNDM patients after 8 years of age, emphasizing the need for prolonged follow-up. Among the 19 TNDM patients tested, two had paternal isodisomy of chromosome 6, seven from 4 families had paternally-derived trisomy of the 6q region, and two had a methylation defect in the 6q24 region. No chromosome 6 anomalies were found in the 9 PNDM patients tested. CONCLUSION: When present, a chromosome 6 abnormality is strongly in favor of the "transient" form of the disease.