ESPE Abstracts

Background: Thyroid hormones are necessary for normal child development. Hypothyroidism, associated with insufficient amounts of free triiodothyronine and thyroxine, may not only cause poor growth rate, but also results in impaired central nervous system development. In Poland, newborn screening for congenital primary hypothyroidism, the incidence of which is reported to be 1:2500- 1:4000 births, has been performed for many years. Secondary hypothyroidism, caused by abnormal TSH production in the pituitary gland, is much rarer (about 1:16000). POU1F1 gene mutation causes not only TSH deficiency, but also growth hormone and prolactin deficiency.

Case report: The boy was consulted for the first time by an endocrinologist at the age of 5 months during diagnosis of insufficient growth of body weight and body length. The baby was born from a normal pregnancy, delivered by Caesarean section in 41hbd, in good general condition, weight 3350g, length 54 cm . Neonatal period was complicated by increasing jaundice, requiring phototherapy. Because of delayed psychomotor development in the infant, pediatric and neurological diagnostics was performed. Normal TSH levels and very low serum levels of peripheral thyroid hormones were found. During the endocrinological diagnosis, pituitary hypothyroidism was confirmed by the TRH test, pituitary-adrenal axis disorders were excluded. IGF-1 concentration was below normal. Ultrasound examination visualized typical thyroid tissue in an anatomical location. Magnetic resonance imaging visualized a normal small pituitary gland. The cause of central hypothyroidism was determined by genetic testing - PROP1 gene mutation was excluded, POU1F1 mutation was confirmed. The boy is treated with levothyroxine with a good effect. When the patient became euthyroid, he was diagnosed with growth hormone deficiency. Actually during therapy with recombinant growth hormone we observed increasing velocity of growth.

Results: 1. A normal screening result does not exclude central congenital hypothyroidism. 2. Whenever hypothyroidism is suspected, serum TSH and fT4 should be measured in the newborn to initiate treatment as soon as possible. 3. Early diagnosis of hypothyroidism, growth hormone deficiency and appropriate treatment gives a chance for normal development of the child.