Follow-up of infarcts with congenital hypothyroidism detected by neonatal screening in Guangzhou, China

We report a follow-up study of 13 patients with congenital hypothyroidism (CH) detected from 92,067 babies in a screening programme by TSH determination. The follow-up period ranged form 8 months - 6 years. II infants had clinical symptoms at diagnosis. In 9 infants the serum T4 concentrations were below normal (reference range 8-13 mu g/dl). 9 cases had retarded bone age. 8 infants were given TC99m scan at 2 years of age: 3 were thyroid-absent, 4 had an ectopic gland and I had eutopic gland. The mean age at the start of treatment was 57.5 +/- 24.8 days, and the starting T4 dose was 6.25 +/- 0.76 mg/kg (equivalent to LT4 10.4 +/- 1.27 mu g/kg). In 9 infants, serum T4 at I year of age was 12.16 +/- 2.41 mu g/dl. In 7 infants, sei-um T4 at 2 years of age was 11.8 +/- 2.85 mu g/dl and their mean full-scale IQ score (FIQ), verbal and performance Ie scores (Vie, PIQ) were 92.3 +/- 11, 90.7 +/- 12.8 and 93.9 +/- 11.1 respectively. FIQ was significantly lower than that of standardized control (100 +/- 15, P < 0.05. The low FIQ may be related to severe prenatal hypothyroidism, treatment delay and unstable bioactivity of desiccated T4. There was no close relationship between the biochemical and clinical features (P > 0.05). However, the sample number was too small for proper correlation analysis.