Thyroid hypoplasia as a cause of congenital hypothyroidism in Williams syndrome.
ABSTRACT In the Williams-Beuren syndrome (WBS), disorders of the thyroid function and morphology have been reported and programs of thyroid screening and surveillance are recommended. However, the frequency of biochemical thyroid assessment, particularly in the first year of life, is being debated. In this report we describe an infant with WBS and congenital hypothyroidism, due to an important thyroid hypoplasia. The patient, a 1-month-old female, negative at primary neonatal thyroid screening, was referred to our hospital for dyspnea. Thyroid function tests showed a raised TSH (42 mIU/l; normal range 0.5-4 mIU/l) with a low FT(4) concentration (10.21 pmol/l; normal range: 10.29-24.45 pmol/l). Ultrasound examination of the neck showed a significant thyroid hypoplasia, whereas (99m)Tc-pertechnetate thyroid scintigraphy evidenced a thyroid gland in normal position, with reduced shape and overall weak fixation. Therefore, treatment with L-thyroxinewas started. Thyroid hypoplasia is a frequent characteristic of WBS and abnormalities of thyroid function are common in patients with this feature. Therefore, the possibility of congenital hypothyroidism should always be taken into consideration too and, even if congenital hypothyroidism neonatal screening is negative, thyroid (morphology and function) evaluation should be regularly assessed when the diagnosis is made and, thereafter, every year in the first years of life.
Gene 12/2011; 494(1):102-4. DOI:10.1016/j.gene.2011.12.007 · 2.08 Impact Factor
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ABSTRACT: Congenital hypothyroidism is the most frequent endocrine disorder in neonates. Controversy exists regarding the necessity to adjust current screening programs to also diagnose patients with central hypothyroidism or those with mild forms of congenital hypothyroidism, who have high TSH levels but normal T(4) and normal T(3) levels (also known as 'subclinical hypothyroidism'). Thyroid hormone replacement should start as soon as the diagnosis is confirmed by measurement of elevated TSH and low serum thyroid hormone levels. Further diagnostic approaches, such as ultrasonography, scintigraphy and measurement of thyroglobulin levels, to determine the subtype of congenital hypothyroidism, should not delay initiation of treatment. Recommendations regarding the initial dosage of levothyroxine vary considerably, and no general accepted guideline exists with regards to initial dosage or optimal time point for dose adjustment according to biochemical parameters. More than 30 years after the introduction of the first neonatal screening programs, mental retardation can be prevented in the majority of children (>90%) with congenital hypothyroidism if therapy is commenced within the first 2 weeks of life, making neonate screening for this disorder the most successful population-based screening test in pediatrics.Nature Reviews Endocrinology 02/2012; 8(2):104-13. DOI:10.1038/nrendo.2011.160 · 12.96 Impact Factor