The Study On Prevalence And PKU Etiological Significance Of Children With MR In A Rural Area Of Anhui Province

Objectives To describe the prevalence of children with mental retardation (MR) aged 4 to 17 years and its feature of distribution in a rural area in Anhui Province and discuss the effect of biomedical and social-psychological factors on the children with MR. To know its etiological significance in MR by screening a kind of particular inheritance metabolism disease called Phenylketonuria (PKU) in children with MR. To locate lesion areas in brain of the patients utilizing conventional magnetic resonance imagery (MRI). Diffusion-Weighted Imaging (DWI) and Magnetic Resonance Spectroscopy (MRS) were used on lesion areas in brain to explore the pathological changes of brain and discuss the relations among blood Phe, MRI grades and patients intelligence quotient(IQ) .Methods A total of 11360 children aged 4 to 17 years were selected from 24 villages in a town in a rural area of Anhui Province. They were screened on intelligence by one to one survey. Positive children among them were tested by Wechsler intelligence scale for children (WISC) and were assessed on social adaptation. Eighty-three children were diagnosed as MR. All of them underwent physical examination and were investigated by self-made questionnaire.With exclusion of 8 children with definitely etiological factors of MR, 75 children consisted of the case group. Through 1:2 matched by age and sex, 150 children without birth defect were considered as controls that had normal intelligence. All of them were tested on intelligence by WISC, social adaptation and investigated by questionnaire. Firstly, univariate analysis was used to find risk factors and then explored the main risk factors for MR by COX regression (to modeling multiple conditional Logistic regression).Children aged 4 to 17 years were screened on IQ in 3000 natural villages from 30 towns in the rural area. Among them 779 children had abnormal intelligencedevelopment. They were screened on PKU by Guthn'e bacterial inhibition assay (GBIA). Eight children were diagnosed as PKU (all of them without diet control). Five patients among them after informed consent voluntarily participated in the MR1 study on brain and were considered as the untreated group, while the other four definitely diagnosed by the neonatal screening center were offered diet control and considered as the treated group. The two groups were tested on IQ by WISC and blood Phe levels were assessed by the semi-quantitative determination. Nine normal children matched by age were considered as control who had no impairment or abnormal function on brain. We examined the two PKU groups by conventional MRI. described the manifestation of MRI on brain in the treated and untreated group and analyzed the relations among IQ, MRI grades and blood Phe level. DW1 and 1H-MRS were used to explore the pathological changes of lesion areas in brain and biochemical metabolism changes. Results The total prevalence rate of children aged 4 to 17 years old with MR was 7.31 %. The prevalence in male and female were 8.06%o and 6.27%o respectively.The children with MR in severe degree in female were more than those in male. The children aged 10 to 17 years old with MR in middle degree were more than those aged 4 to 9 years old. The first five types of birth defect and developmental disorders in children with MR were motor disorder of lower limbs, motor disorder of upper limbs, epilepsy, equinovarus, Visual disturbance respectively. Occurrence of neonatal febrile, convulsion, neonatal pneumonia, asphyxia of newborn were significantly different in children with MR in different degrees.By univariate analysis 11 risk factors were explored: family poverty, low culture level of mother, history of family on MR or epilepsy in parents, abnormal menstrual cycle before pregnancy, febrile in gestation period, bleeding in gestational period, chronic disease in gestational period, premature birth, cry after birth with the help of assistance, neonatal febrile, convulsion and asphyxiation. By COX regression analysis the results revealed 5 factors including MR in parents...