Beschreibung:
<jats:p>The consequences of using low blood-spot thyroid-stimulating hormone (b-TSH) cut-off values for newborn screening of congenital hypothyroidism (CH) are largely unknown. Therefore, the impact on CH epidemiology and classification generated by the introduction in our Italian region of a low b-TSH cut-off during 1999–2005 was retrospectively examined. This work was recently performed in collaboration with the Laboratory for Neonatal Screening and the Principal Follow-up Centre of the Lombardy region. The incidence of CH in this Italian population was 1:1,446 live births, with a predominance of functional over morphogenetic defects. The use of low b-TSH cut-offs allowed the detection of an unsuspected number of children with neonatal hypothyroidism, evolving to mild permanent thyroid dysfunction later in life. Premature birth was associated with a three- to five-fold increased risk of CH with gland<jats:italic>in situ</jats:italic>.</jats:p>