School attainments in children with congenital hypothyroidism detected by neonatal screening and treated early in life

Objective: Evaluation of school attainments in children with congenital hyp othyroidism (CH) detected by neonatal screening and treated early in life, Patients and methods: Text comprehension, mathematics, reading, writing and verbal and spatial memory, as indices of school learning, were evaluated i n nineteen 5- to 10-year-old children with CH attending nursery or elementa ry school. L-Thyroxine substitution (starting dose 8-10 mu g/kg body weight per day) was initiated at a mean age of 30 +/- 10 days of life, The contro l group included 298 unaffected children matched with the CH children for a ge and school grade. Thirty per cent of controls were classmates of CH chil dren. Intelligence quotients (IQ), language performances and motor developm ent were evaluated in CH children at age 5 years, and were related to their school attainments. School performances of CH children were also compared with their neonatal serum thyroxine (T-4) concentration, and with the socia l-cultural level of the family. Results: Four out of 19 (21%) children with CH, 3 in the nursery and 1 in t he elementary school, displayed a generalized learning disorder. Symbol cop y, geometric copy phrase repetition, dictation writing and spontaneous writ ing were particularly defective in nursery school CH children, while orthog raphic error recognition was defective in elementary school CH children. Sc hool learning disorders in CH children were significantly correlated with a borderline-low IQ, poor language performances and a low social-cultural le vel of the family, but not with motor skills or neonatal T-4 concentration. Conclusion: School attainments of early treated CH children were within the normal range in most affected cases. However, about 20% of CH children, mo st of them attending nursery school, showed a generalized learning disorder . Low IQ scores and poor language performances at age 5 pears were associat ed with defective learning, mainly in CH children living in a poor social-c ultural environment. In this subset of CH children, prompt initiation of sp eech and psychomotor rehabilitation therapy is recommended in order to prev ent subsequent school learning disorders.