Author(s): Congenital, hypothyroidism, Saudi Arabia, screening
Congenital hypothyroidism (CH) represents one of the most common preventable causes of mental retardation. Neonatal screening programs for CH have almost eliminated the problem of severe mental retardation previously observed in infants who were not diagnosed and treated early in infancy. Screening either utilizes cord blood or an elute of whole blood collected on filter paper by heel prick on day 5-7 of life. Screening based on either the primary determination of serum thyroid screening stimulating hormones senthyroxine or determination of (T4) with back-up of TSH determination for infants with the lowest (10%) of T4 levels has been used. In Saudi Arabia, the programs utilize cord TSH determination. Of 1,007350 newborns screened, 306 infants were diagnosed to have CH, indicating an incidence of 1:3292. A regional variation in the incidence was observed. Of all infants with CH who were adequately studied, 147 infants, the gland was found to be aplastic in 32 (21.8%), while in 62 (42.2%) the gland was ectopic. Thyroid hormone dyshormonogenesis was present in 53 infants (36%). An increased risk of other congenital anomalies was noted. Also, a transient iodine organification defects in infant with ectopic thyroid gland was reported.