ß 2008 Wiley-Liss, Inc. American Journal of Medical Genetics Part A 146A:2637–2643 (2008) High Prevalence of Orofacial Clefts in Shanxi Province in Northern China, 2003–2004 Zhiwen Li,* Aiguo Ren, Jianmeng Liu, Le Zhang, Rongwei Ye, Song Li, and Zhu Li* Institute of Reproductive and Child Health, Peking University Health Science Center, People’s Republic of China Received 16 October 2007; Accepted 19 June 2008 Shanxi Province in northern China has been identified as an area with the highest prevalence of neural tube defects in the world; however, few reports exist on the prevalence of orofacial clefts (OFC). We examined the prevalence of OFC and their association with selected characteristics. Data came from a population-based birth defects surveillance system in four counties of Shanxi Province. The system captures information on all live births, stillbirths of at least 20 weeks gestation, and pregnancy terminations at any gestational age after prenatal diagnosis of a birth defect. Out of 25,355 births in 2003–2004, 83 cases with orofacial clefts were identified resulting in a birth prevalence of 3.27 per 1,000. Other major external birth defects were present in 12 (14.5%) OFC cases. Cleft lip with palate (CLP), cleft lip alone (CL) and cleft palate alone (CP) accounted for 62.0%, 29.6% and 8.4% of OFC cases without additional external defects, respectively. The male to female ratio was 1.04 (95%CI: 0.67 – 1.60) for all OFC, 1.46 (95%CI: 0.80–2.68) for CLP, 1.23 (95%CI: 0.52–2.91) for CL, 0.46 (95%CI: 0.08–2.51) for CP without additional major external defects, and 0.31(95%CI: 0.08–1.13) for OFC with additional external defects. The prevalence of OFC without additional external defects was increased with decreased maternal age (P < 0.05) and increased maternal education (P < 0.05). The birth prevalence of OFC in Shanxi Province of northern China is among the highest worldwide. Further studies are required to define the factors associated with excess risk of clefts. ß 2008 Wiley-Liss, Inc. Key words: orofacial clefts; cleft lip; cleft palate; cleft lip with palate; prevalence; epidemiology How to cite this article: Li Z, Ren A, Liu J, Zhang L, Ye R, Li S, Li Z. 2008. High prevalence of orofacial clefts in Shanxi Province in northern China, 2003 – 2004. Am J Med Genet Part A 146A:2637 – 2643. INTRODUCTION Orofacial clefts (OFC) are one of the most commonly reported major birth defects in hospital- based surveillance in China [International Clearing- house for Birth Defects Surveillance and Research, 2006]. These defects are usually associated not only with cosmetic concerns but also dental problems, facial growth difficulties, and speech and hearing abnormalities. The etiology of the clefts is generally thought to be multifactorial involving both genetic and environmental factors [Wyszynski, 2002]. OFC occurs in individuals of all socioeconomic and ethnic backgrounds. The birth prevalence of orofacial clefts varied in different populations and is generally less than 2 per 1,000 births [Derijcke et al., 1996; Croen et al., 1998; Jaber et al., 2002; International Clearing- house for Birth Defects Surveillance and Research, 2006]. Shanxi Province, located in north central China, has been identified as a region with the highest prevalence of neural tube defects worldwide [Li et al., 2006a]. However, little data has been reported on the prevalence of OFC in this population. The aim of this study is to examine the prevalence of OFC and their association with some selected demographic char- acteristics in Shanxi Province. METHODS Study Population and Case Ascertainment The data came from a population-based birth defects surveillance system covering four counties (Pingding, Xiyang, Taigu, and Zezhou) of Shanxi Province in Northern China. The surveillance system as described previously [Li et al., 2006a], detects external structural defects from all live births, Grant sponsor: The Key Technologies Research and Development Program of the Tenth Five-Year Plan for the Nation Scientific and Technological Development of the People’s Republic of China; Grant number: 2002BA709B11. *Correspondence to: Dr. Zhiwen Li, M.D., Ph.D., or Dr. Zhu Li, M.D., MPH, Institute of Reproductive and Child Health, Peking University Health Science Center, 38 Xueyuan Rd., Haidian District, Beijing 100083, China. E-mail: lizw@ncmih.bjmu.edu.cn; lizhu3699@gmail.com Published online 16 September 2008 in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/ajmg.a.32492