Predictive outcome measures of adult short stature in patients with severe acquired autoimmune hypothyroidism. / Variables predictivas de talla baja adulta en pacientes con hipotiroidismo adquirido grave de origen autoinmune.

Hypothyroidism caused by Hashimoto's thyroiditis is the most common reason for thyroid dysfunction in children. Our objective was to analyze its impact on final stature in relation to height and pubertal stage at the time of diagnosis in children younger than 18 years with severe autoimmune hypothyroidism. Out of 79 patients, 78.5 % were girls. Those with goiter (56 %) had a better height at diagnosis than those without goiter (mean standard deviation score for height: 0.2 versus -2.42; p < 0.0001). Five girls (6.3 %) had precocious puberty. When considering the final stature of patients (n: 33), among those with short stature at the time of diagnosis, pubertal children had a significantly shorter final stature than prepubertal children (mean standard deviation score for height: -2.82 versus -1.52; p = 0.0311). The late diagnosis of severe hypothyroidism in pediatrics has a negative impact on final stature, especially in those who were pubertal patients at the time of diagnosis.

El hipotiroidismo por tiroiditis de Hashimoto es la causa más frecuente de disfunción tiroidea en niños. Nuestro objetivo fue analizar el impacto en la talla final según la talla y el estadio puberal al momento del diagnóstico en menores de 18 años con hipotiroidismo grave de origen autoinmune. De los 79 pacientes, el 78,5 % fueron mujeres. Los que presentaron bocio (el 56 %) mostraron mejor talla en el diagnóstico que los que no lo tenían (puntaje de desvío estándar de media de talla: 0,2 vs. -2,42; p < 0,0001). Cinco niñas (el 6,3 %) presentaron pubertad precoz. De los pacientes con talla final (n: 33), dentro de los que presentaron talla baja al momento del diagnóstico, los púberes tuvieron una talla final significativamente menor que los prepúberes (puntaje de desvío estándar media: -2,82 vs. -1,52; p = 0,0311). El diagnóstico tardío de hipotiroidismo grave en pediatría tiene un impacto negativo en la talla final, especialmente, en los pacientes puberales al momento del diagnóstico.

The C105fs114X is the prevalent thyrotropin beta-subunit gene mutation in Argentinean patients with congenital central hypothyroidism.

BACKGROUND: Congenital isolated thyrotropin (TSH) deficiency is an unusual condition characterized by low levels of thyroid hormones and TSH, usually presenting early typical signs of severe hypothyroidism. Five different beta-TSH mutations have been described so far. While 4 of them affect only consanguineous families, a frameshift mutation in exon 3 (C105fs114X) has been found also in nonconsanguineous families. OBJECTIVE: The aim of the present study was to characterize beta-TSH mutations in Argentinean patients with congenital central hypothyroidism (CCH) and to emphasize the importance of early biochemical and molecular diagnosis of this disorder. PATIENTS AND METHODS: We investigated 8 Argentinean children (3 boys, 5 girls) from 7 unrelated families with CCH based upon low levels of T(4) and T(3), and low basal and stimulated TSH levels. Mutation characterizations for the beta-TSH gene were performed by PCR amplification followed by sequence and restriction enzyme analysis with SNABI in the patients, 9 parents and in 100 newborn children. RESULTS: All patients presented the same homozygous mutation in exon 3 of the beta-TSH gene (C105fs114X), the 9 studied parents were heterozygous for the same mutation and 1 carrier was found in the 100 studied newborns. CONCLUSION: Our findings show that the C105fs114X mutation is prevalent in our population and may constitute a hot spot at codon 105 in the beta-TSH gene. Since this mutation is easily demonstrable by a SNABI digestion in DNA amplified from dried blood spots, its investigation would be indicated in patients in our milieu with clinical and biochemical features of CCH, allowing early L-thyroxine (LT(4)) replacement and genetic counseling of the family.