Background: Mental retardation, considered as common in Apert syndrome could be in part due to associated brain abnormalities.
Population and methods: Sixty patients (32 males, 28 females) were included in the study. Patient age at the last examination was over 3 years (mean 10 years, range 3-28 years) in 38 patients. IQ was assessed from psychometric tests adapted for age. Brain anatomy was studied by MRI. Age at operation and quality of familial environment were also evaluated.
Results: The IQ was over 70 in 12 patients (32%), over 90 in five (13%) and the mean IQ was 62 (10-114). Thirty percent of patients had abnormalities of the corpus callosum, 43% of the cerebral ventricles and 55% of the septum pellucidum. There was no anomaly in 28% of the patients. One or more operations were performed in 53 patients, before one year of age in 37. Ten children were institutionalized or in deleterious family situation. The main factor influencing the mental prognosis was the age at operation: the final IQ was over 70 in 50% of the children operated on before one year of age versus 8% in those operated on later (P = 0.01). Only the anomalies of the septum pellucidum seemed to play a role: 50% of the patients with normal septum had an IQ > 70 compared to 18% in those with septum anomalies (P < 0.04). The quality of the familial environment also influenced the mental development: 12.5% of the patients who were institutionalized or in difficult familial situation had an IQ > 70 compared to 39% of those who live in a normal family.
Conclusions: Careful investigation including MRI is necessary for detecting associated brain abnormalities. The patients must be operated on early, if possible before the age of nine months. Attention has also to be paid to quality of the sociofamilial environment.