Abstract OBJECTIVE: To explore the chromosome karyotypes in children with mental retardation. METHODS: The peripheral blood lymphocytes from 92 chidren with congenital mental retardation were cultured and analysed by the G-band technique. RESULTS: Of the 92 cases, 43 cases (47%) showed chromosome abnormalities. Autosomal abnormalities were found in 35 cases (38%) and sex chromosome abnormalities were found in 8 cases (9%). A novel abnormal karyotype 45,XX,psu dic（11;9）（p15;p24）was found in a child. CONCLUSIONS: Chromosome abnormalities may be important cytogenetic factors for congenital mental retardation. Cytogenetic chromosome karyotypic analysis appears to be an important method for genetic screening of congenital mental retardation.
［1］Moeschler JB. Medical genetics diagnostic evaluation of the child with global developmental delay or intellectual disability［J］.Curr Opin Neurol, 2008, 21(2): 117-122.
［2］Basel-Vanagaite L. Clinical approaches to genetic mental retardation［J］.Isr Med Assoc J, 2008, 10(11): 821-826.
［3］Guo L, Li BX, Deng M, Wen F, Jiang JH, Tan YQ, et al. Etiological analysis of neurodevelopmental disabilities: single-center eight-year clinical experience in South China［J］.J Biomed Biotechnol, 2011, 2011: 318616.
［4］David S. Disorders usually frist diagnosed in infancy, childhood or adolescence［M］//Moser M, Michael R. Diagnostic and statistical manual of mental disorders. 4th ed. Washington, DC: American Psychiatric Association, 2000: 41-49.
［8］Jeong SY, Kim BY, Yu JE. De novo pericentric inversion of chromosome 9 in congenital anomaly［J］.Yonsei Med J, 2010, 51(5): 775-780.
［9］Saito-Ohara F, Fukuda Y, Ito M, Agarwala KL, Hayashi M, Matsuo M, et al. The Xq22 inversion breakpoint interrupted a novel Ras-like GTPase gene in a patient with Duchenne muscular dystrophy and profound mental retardation［J］. Am J Hum Genet, 2002, 71(3): 637-645.
