CONGENITAL HYPOTHYROIDISM IN WALES (1982-1993) - DEMOGRAPHIC FEATURES, CLINICAL PRESENTATION AND EFFECTS ON EARLY NEURODEVELOPMENT

OBJECTIVE Neonatal screening for congenital hypothyroidism (CH) was in troduced in Wales in 1982. The aim of the study was to evaluate the de mographic features and characteristics of infants identified during th e first 12 years of screening and their neurodevelopmental progress in the first 2 years of life. DESIGN Prospective collection of biochemic al and clinical data (including results of Griffiths Mental Developmen t Scales) obtained from questionnaires sent to paediatricians responsi ble for the ongoing clinical care of children with On. PATIENTS In Wal es, between 1982 and 1993, 136 infants with primary congenital hypothy roidism (CH) were identified by the neonatal screening programme. RESU LTS Of all new-borns, 99.8% were screened and the prevalence of On was 1 in 3279(1 in 2473 girls and 1 in 4770 boys). The prevalence of CH w as increased in North Wales. On was associated with increased birth we ight (48.5% of infants weighed greater than 3.5 kg) and an increased p revalence of non-thyroidal congenital abnormalities (8%) and congenita l heart disease (3%), Isotope scanning demonstrated an increased preva lence of normal or enlarged thyroid glands and fewer ectopic glands co mpared to those reported in other studies. The mean developmental quot ients (DQs) for individual subsets of intellectual and behavioural fun ctioning in children with CH aged 1 and 2 years were all above 100 (ra nge: 103.5-111.9). In subjects with absent thyroids, these DQs were co rrelated with the serum concentrations of free thyroxine before treatm ent. CONCLUSIONS The demographic features of infants with congenital h ypothyroidism born in Wares are similar to those reported from other E uropean studies although there are marked regional variations in preva lence within Wales for which there is no apparent explanation. The med ian age of starting therapy was 17 days and compares favourably with o ther screening programmes, The overall mental development of Welsh chi ldren aged 1 and 2 years with congenital hypothyroidism identified by neonatal screening is satisfactory.