The screening for mutations in the thyroglobulin cDNA from six patients with congenital hypothyroidism.

The six patients described in this study were clinically diagnosed with congenital hypothyroidism. Based on clinical and pathophysiological parameters, the cause of the thyroid dyshormonogenesis was suspected to be a defect in the synthesis of thyroglobulin, the matrix protein for thyroid hormone synthesis in the thyroid gland. After RNA isolation from six goitrous tissues and control thyroid tissues, RT-PCR was used to amplify 20 overlapping thyroglobulin (TG) cDNA fragments. Two alternative splice transcripts were identified: a transcript with a deletion of nucleotides 177-274 and a transcript with a deletion of nucleotides 3430-3736 that result in frame shifts and the introduction of premature stop codons. Two alternatively spliced transcripts not changing the reading frame were also identified: a transcript containing a deletion of nucleotides 4529-4699 and a transcript with a deletion of nucleotides 7301-7561. All these transcripts were expressed in thyroid tissue of both patients and controls. Nucleotide sequence analysis and comparison to the revised TG sequence (1997) revealed one revision and eight polymorphisms that did not result in amino acid changes and four polymorphisms that did change amino acid codons. In three patients a homozygous mutation was present at nucleotide position 229, causing a glycine to serine amino acid substitution. The clinical description 'thyroglobulin synthesis defect' in this population cannot be explained by major mutations in the coding region of the TG gene. Furthermore, the presence and level of expression of the alternatively spliced transcripts do not co-segregate with thyroid dyshormonogenesis, since in normal thyroid tissue the same alternatively spliced transcripts are present.

A 20-basepair duplication in the human thyroid peroxidase gene results in a total iodide organification defect and congenital hypothyroidism.

In this study we present the molecular basis of a total iodide organification defect causing severe congenital hypothyroidism. In the thyroid gland of the patient, thyroid peroxidase (TPO) activity and the iodination degree of thyroglobulin were below detection limits, and no TPO messenger ribonucleic acid was detectable by Northern blot analysis. Denaturing gradient gel electrophoretic analysis of the TPO gene of the patient revealed a homozygous mutation in exon 2. Sequence analysis showed the presence of a 20-basepair duplication, 47 basepairs down-stream of the ATG start codon. This duplication generates a frame shift, resulting in a termination signal in exon 3, compatible with the complete absence of TPO. Both parents of the patient are heterozygous for the same duplication, confirming the recessive mode of inheritance of the mutation.

Growth hormone therapy in Turner's syndrome. Impact of injection frequency and initial bone age.

STUDY OBJECTIVE: To determine the influence of the injection frequency and the initial bone age on the efficacy of treatment with biosynthetic growth hormone in Turner's syndrome. DESIGN: Randomized study. SETTING: Referral-based pediatric endocrinology departments of seven university medical centers. PATIENTS: Fifty-two patients with Turner's syndrome confirmed with chromosomal analysis. TREATMENT: Somatotropin recombinant DNA (24 IU/m2 of body surface area) subcutaneously administered in three or six injections per week for 2 years. Patients who were older than 12 years at the beginning of the study received low doses of estrogen. RESULTS: The following statistically significant findings supported the use of six injections per week compared with three injections per week: the mean (+/- SD) increment in height during 2 years was 11.3 cm (3.8 cm) with six injections vs 8.6 cm (3.4 cm) with three injections; the increment in height standard deviation score was 0.9 cm (0.5 cm) vs 0.6 cm (0.3 cm); the growth velocity was 6.6 cm/y (2.0 cm/y) vs 5.2 cm/y (1.7 cm/y) in year 1 and 4.7 cm/y (2.0 cm/y) vs 3.4 cm/y (1.7 cm/y) in year 2; and the increment in height standard deviation score for bone age was 0.8 cm (0.5 cm) vs 0.4 cm (0.6 cm). For patients whose initial bone age was more than 13 years, growth velocity increased by 1 to 2 cm in year 1; in year 2 no increment was observed. We did not observe adverse effects. CONCLUSIONS: Biosynthetic growth hormone in a higher-frequency regimen in Turner's syndrome is more efficient in terms of increment in height, growth velocity, and height standard deviation score for bone age than treatment in a lower-frequency regimen. In patients with an initial bone age of more than 13 years, the response was poor. Longer follow-up is necessary to assess the effect on final height.

Growth hormone treatment in Turner syndrome accelerates growth and skeletal maturation. Dutch Growth Hormone Working Group.

Sixteen girls with Turner syndrome (TS) were treated for 4 years with biosynthetic growth hormone (GH). The dosage was 4 IU/m2 body surface s.c. per day over the first 3 years. In the 4th year the dosage was increased to 6 IU/m2 per day in the 6 girls with a poor height increment and in 1 girl oxandrolone was added. Ethinyl oestradiol was added after the age of 13. Mean (SD) growth velocities were 3.4 (0.9), 7.2 (1.7), 5.3 (1.3), 4.3 (2.0) and 3.6 (1.5) cm/year before and in the 1st, 2nd, 3rd and 4th year of treatment. Skeletal maturation advanced faster than usual in Turner patients especially in the younger children. Although the mean height prediction increased by 5.6 cm and 11 of the 16 girls have now exceeded their predicted height, the height of the 4 girls who stopped GH treatment exceeded the predicted adult height by only 0 to 3.4 cm.

The role of serum thyroglobulin concentration and thyroid ultrasound imaging in the detection of iodide transport defects in infants.

When discovered by neonatal screening, a thyroid dyshormonogenesis is usually not recognized as a goitre. Especially a total iodide transport defect can easily be misclassified as thyroid agenesis, since radionuclide imaging cannot visualize the thyroid. We present the only iodide transport defect ever discovered in the Netherlands, the 35th reported in the literature, and the first one found exclusively as a result of neonatal screening. We demonstrate that iodide transport defects, in common with organification and deiodinase defects, can be distinguished from thyroid dysgenesis by demonstrating a normal or enlarged thyroid ultrasound image, and especially by measuring very high serum thyroglobulin levels (above 1000 pmol/l). In the presented case, an iodide-123 saliva-to-serum ratio near unity completed the etiologic classification. Measurement of serum thyroglobulin levels, in combination with thyroid ultrasound imaging, will improve the early identification of hereditary types of congenital hypothyroidism, and especially iodide transport defects, in patients found by neonatal thyroid screening.

Two-year results of treatment with methionyl human growth hormone in children with Turner syndrome. Dutch Growth Hormone Working Group.

Methionyl growth hormone (somatrem) in a daily dosage of 4 IU/m2 body surface area was administered to 16 girls with Turner syndrome. Low dose ethinyl estradiol (0.1 microgram/kg body weight) was added in girls aged 13 years or more. Mean (SD) height velocity increased from 3.4 (0.9) to 7.2 (1.7) and 5.3 (1.3) cm/year in the first and second year, respectively. Bone age advanced 1.8 years over 2 years and predicted adult height was increased. Apart from the occurrence of anti-GH antibodies there were no side effects. In conclusion, somatrem is an efficacious and safe therapy for short stature in Turner syndrome over a period of 2 years. Longer follow-up is needed before conclusions about its effect on final height can be drawn.

Maternal-fetal transfer of thyroxine in congenital hypothyroidism due to a total organification defect or thyroid agenesis.

The fact that neonates who subsequently have severe hypothyroidism have no evidence of the condition at birth suggests the possibility of the placental transfer of thyroid hormones. Recent studies have demonstrated the existence of such transfer in hypothyroid rats. To determine whether there is a transfer of thyroxine (T4) from mother to fetus, we studied 25 neonates born with a complete inability to iodinate thyroid proteins and therefore to synthesize T4. This total organification defect is an autosomal recessive disorder with an incidence of approximately 1 in 60,000 neonates in the Netherlands. In the cord serum of affected neonates, T4 levels ranged from 35 to 70 nmol per liter. Since these patients were unable to produce any T4, the T4 must have originated in their mothers. The estimated biologic half-life of serum T4 was 3.6 days (95 percent confidence interval, 2.7 to 5.3). In 15 neonates with thyroid agenesis, the serum levels and the disappearance kinetics of T4 were the same as those in the neonates with a total organification defect, suggesting that in these infants, the T4 also had a maternal origin. We conclude that in infants with severe congenital hypothyroidism, substantial amounts of T4 are transferred from mother to fetus during late gestation.

The poikiloderma of Rothmund-Thomson syndrome: changes in Langerhans cell morphology and distribution.

A black girl with the Rothmund-Thomson syndrome is presented. Immunophenotyping of subpopulations of immunocompetent cells in a biopsy of an atrophic hyperpigmented skin lesion revealed sparsity and unusual distribution of epidermal Langerhans cells. These cells were mainly located in the basal layer of the epidermis and did not show the usual dendritic pattern. Impressive immunoreactivity of the dermal infiltrate was observed by anti-HLA-DR staining. The changes in Langerhans cell morphology and distribution may indicate functional impairment of the up-regulating arm of skin immunity.

Methionyl human growth hormone in Turner's syndrome.

Sixteen girls with Turner's syndrome aged 7.9-15.2 years (bone ages 7.0-11.8 years) were given methionyl growth hormone (somatrem) 4 IU/m2 body surface daily, corresponding to 0.9 IU/kg/week. During one year of treatment their mean (SD) height velocity increased from 3.4 (0.9) to 7.2 (1.7) cm/year and height prediction from 148.2 (4.4) to 150.0 (4.4) cm. All the girls except one had a height velocity increment of more than 2 cm/year and these velocities are above the age references for girls with Turner's syndrome. The girl with a low growth response had antibodies against growth hormone with high binding capacity (3.7 U/l). The height velocity increment was inversely correlated with age and bone age, but this might be partly due to the somewhat higher dosage/m2 body surface and kg body weight that the younger patients were given because of the rounding off of the dose. The better results of our study compared with those of other workers who used similar dosages but did not give the drug as often suggest that giving it daily might have increased the growth response as it does in children deficient in growth hormone.

[Ambulatory treatment and monitoring of children with insulin-dependent diabetes mellitus (IDDM)]. / De ambulante behandeling en begeleiding van het kind met insuline afhankelijke diabetes mellitus (IDDM).

In recent years diabetes research has made substantial progress. Insight in epidemiology, aetiology, patho-physiology of diabetes and pharmacokinetics of insulin is increased. Furthermore the development of self-monitoring has changed the management of diabetes. In this paper the consequences of this progress for modern ambulatory treatment of diabetes in childhood are discussed.

[Congenital hypothyroidism. Current viewpoints and developments]. / Congenitale hypothyreoïdie. Nieuwe inzichten en ontwikkelingen.

Since 1978 neonatal screening on congenital hypothyroidism (CHT) is performed in The Netherlands. A combined T4 and TSH determination is used. This creates the possibility to detect secondary and tertiary hypothyroidism. The number of false-positive cases is relatively high. This number decreases by adjusting the method of screening. Recent studies show a CHT incidence of 1:2100 newborns. In about 25% of these cases the CHT appears to be transient. Proceeding from the screening on CHT several investigations presented in this review are in progress.

Prenatal diagnosis of a thyroglobulin synthesis defect in goats.

A strain of goats with congenital goitre due to a thyroglobulin (Tg) synthesis defect was studied. All goats excreted low molecular weight iodinated material (LOMWIOM) in their urine, but non-goitrous goats excreted in the LOMWIOM fraction less than 5 micrograms iodine per 24 h and the goitrous ones more than 15 micrograms iodine per 24 h. Prenatal diagnosis of the Tg synthesis defect in goats is possible since non-goitrous goats pregnant with goitrous kids excrete in the LOMWIOM fraction more than 10 micrograms iodine per 24 h while non-goitrous goats pregnant with non-goitrous kids excrete 10 micrograms or less iodine per 24 h as LOMWIOM. In 24 out of 25 cases a correct diagnosis could be made in the last 47 days of pregnancy. We argue that prenatal diagnosis of analogous defects in man may also be possible, using the excretion of LOMWIOM in maternal urine as yard-stick. By means of field desorption mass spectrometry (FOMS) and high performance liquid chromatography (HPLC) monoiodohistidine was identified as the major component of the LOMWIOM fraction in the urine of goitrous goats.

Concentration of plasma thyroglobulin and urinary excretion of iodinated material in the diagnosis of thyroid disorders in congenital hypothyroidism.

In this paper we describe methods for the early aetiological diagnosis of congenital hypothyroidism, using beside the classical T4, T3 and TSH plasma concentrations, four additional parameters in plasma and urine. The first one is thyroglobulin (Tg). In normal children of more than one year of age and in adults, 5-35 ng/ml plasma is found, in neonates 2-3 weeks old, this level is 10-250 ng/ml. In patients with a stimulated thyroid gland, as in primary congenital hypothyroidism, plasma Tg levels increase. High Tg values are found in iodine deficiency and in organification defects. In the absence of the thyroid gland plasma Tg is undetectable. Low to normal levels are found in cases with hypoplasia of the gland. In patients with a disturbed synthesis of Tg, resulting in Tg deficiency of the gland, plasma Tg levels vary from undetectable to normal. The PBI-T4 plasma difference, which is caused by circulating abnormal iodoproteins is the second parameter. The products of thyroidal breakdown processes of the abnormal iodoproteins are excreted in the urine and used as the third parameter. We found that the excretion of this low molecular weight iodinated material (LOMWIOM) was increased only in Tg-deficient patients. If the neonate is found to be hypothyroid, thyroid hormone substitution must be given immediately. Blood and urine sampling can be done just before or even directly after starting the therapy. The measurements extended with the determination of the total iodine excretion (fourth parameter) can be carried out within 1 week. With these additional methods it appeared to be possible to distinguish between several types of congenital hypothyroidism in neonates found by screening.

Serum thyroglobulin levels: the physiological decrease in infancy and the absence in athyroidism.

The cord serum thyroglobulin levels of 218 neonates are much higher than the levels after the first year of life and show a wide range. A relation exists between a shorter gestational age and increased thyroglobulin levels. The serum thyroglobulin levels decrease within a few months after birth, but throughout the first year of life, these levels are still higher than the normal values at later ages (5-35 ng/ml). IN 3 athyroid children, thyroglobulin is undetectable in serum.