POSTER NO: 371

The genetic component of intellectual disability in PR China

¹Wei Wang, ¹Sheena G. Sullivan, ²Jing-Chuan Yao, ³Yan Liu, ²Cheng-Zhi Che, ¹Alan H. Bittles
¹Centre for Human Genetics, Edith Cowan University, Perth, Australia, ²Chinese Disability Association, Beijing, PR China, ³Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, PR China

To date, research into the prevalence and causes of intellectual disability in developing countries has been limited. The national survey conducted in PR China during 1987 was a notable exception. For the survey, a national representative sample comprising 1.58 million individuals, i.e. 0.15% of the total Chinese population was collected. Three categories of intellectual disability were defined in terms of IQ level: mild, IQ 50-70, moderate, IQ 35-50, and severe, IQ< 20-35, derived by reference to the definitions of American Association of Mental Retardation and World Health Organization classification. The overall prevalence of intellectual disability was 1.27%, equivalent to an estimated 13.4 million persons in the total contemporary population. There was a preponderance of males (sex ratio 1.10) and the highest prevalence of intellectual disability was reported in the age range 12-26 years. In general, the highest rates of intellectual disability were recorded in rural areas. However, there was considerable variation in prevalence from 2.44% in the North-east province of Jilin to 0.58% in metropolitan Beijing. The majority of intellectual disability cases were mild (49.7%), followed by moderate (32.5%) and severe disability (17.8%). In 13.9% of cases a genetic aetiology was reported; over 20% of which were severe. The information from this survey provides a useful baseline against which future trends in intellectual disability can be assessed, in particular the growing recognition of underlying genetic causes.