Genetic Epidemiology of Cleft Lip and Palate

Clefts of the lip and palate are birth defects with multifactorial etiology, involving important surgical, speech, social, behavioral, and developmental implications. Approximately 70% of clefts are nonsyndromic - they do not involve other types of abnormalities such as shorter limbs, shorter digits (toes or fingers), wider set eyes, and many other symptoms. A number of environmental factors also play a role in craniofacial deformities. These factors include nutritional deficiencies such as insufficient folic acid consumption or absorption, smoking, and alcohol consumption, factors relevant to socioeconomic status. The purpose of this review is to present information concerning cleft lip and palate that has been observed and confirmed in past studies, apply this information to reviews of recent epidemiological and molecular genetics studies, evaluate factors surrounding these complex diseases, and create suggestions or questions applicable to future research. The papers reviewed include the examination of candidate genes, environmental factors, or a combination of both. Differences in disease distribution in populations will also be discussed