Iodine deficiency is the major cause of an increase in thyroid gland volume in infants and children. In this field study we monitored the iodine supply and its effect on the thyroid gland volume in prepubertal and pubertal children in the eastern and western parts of the city of Berlin, so far considered as an area with borderline iodine deficiency. The thyroid gland volume was determined by ultrasound in 1080 (f = 552, m = 528) children aged 3-15 years, and was correlated to age, body-surface area and iodine excretion, which was measured in a first-morning spot urine. The mean iodine concentration was 115.8 micrograms iodine/g creatinine (12.2 micrograms iodine/dl urine), with no significant differences between eastern parts with 114.5 micrograms iodine/g creatinine (12.3 micrograms iodine/dl urine) vs 116.7 micrograms iodine/g creatinine (12.0 micrograms iodine/dl urine) in the western parts of the city. This good iodine supply of the children was surprising compared to former studies in children and adults. Moreover this normalization of the iodine excretion was reflected by smaller thyroid gland volumes in the children. The volume was found to increase with age and was 2.4 +/- 1.1 ml in prepubertal (Prader and Largo: f < or = 10.9 ys, m < or = 11.5 ys) children, compared to 4.3 +/- 1.7 ml in pubertal children. The goiter prevalence, calculated on this data was below 5%. Among all children there were only 11 (aged 8-13 ys) with abnormal findings of the thyroid gland on ultrasound: 6 with small nodules, 1 girl with a thyroid-cyst, 2 girls had an inhomogenous echo structure and 2 girls presented with a hemithyroidea. This study shows that the iodine supply of the children in Berlin has improved, resulting in smaller sized thyroid glands, compared to those which have been previously published for Germany (Müller-Leisse 1988; Klingmüller, 1991; Menken, 1992), but they correspond well to volumes described in countries with sufficient iodine supply.

Isolated TSH deficiency leading to hypothyroidism seems to be a rare condition, escaping the diagnosis by neonatal screening programs, which are based on the primary determination of TSH. This is the first report of a case with an autosomal recessive TSH defect caused by a homozygous mutation of the betaTSH gene that was diagnosed in the early neonatal period. Hypothyroidism in the first child of apparently unrelated parents was suspected because of the classical symptoms of congenital hypothyroidism, which were fully expressed already on the 11th day of life. Routine neonatal TSH-screening on the 4th day of life had been normal, but subsequent determination of serum thyroid hormone levels revealed almost undetectable levels and thyroid hormone substitution was immediately started. Because there was no indication for other pituitary hormone deficiencies, sequence analysis of the betaTSH gene was initiated. A homozygous T deletion in codon 105 was found resulting in a change of a highly conserved cysteine to valine followed by eight altered amino acids and a premature stop codon due to the frame-shift. This altered betaTSH is a biologically inactive peptide. Because of the early development of severe symptoms, it is possible that this altered TSH suppresses the physiologic constitutive activity of the unliganded TSH receptor. Rapid molecular diagnosis in this patient clarified the diagnosis without additional endocrine and imaging studies and it is concluded, that symptoms of hypothyroidism in the neonatal period should result always in an immediate comprehensive work-up of thyroid function including molecular genetic studies irrespective of the screening result.

HbA1c seems to be more reliable than OGTT for diabetes screening in overweight and obese children and adolescents. The optimal HbA1c threshold for identifying patients with diabetes was found to be 42 mmol/mol (6.0%). What is Known: • The prevalence of obesity is increasing and health problems related to type 2 DM can be serious. However, an optimal screening test for diabetes in obese youth seems to be controversial in the literature. What is New: • In our study, the ROC analysis revealed for FPG an optimal threshold of 98 mg/dl (5.4 mmol/l, sensitivity 70%, specificity 88%) and for HbA1c a best cut-off value of 42 mmol/mol (6.0%, sensitivity 94%, specificity 93%) to detect diabetes. Thus, in overweight and obese children and adolescents, HbA1c seems to be a more reliable screening tool than OGTT.