Recurrence Risk for Siblings of Cleft Lip/Palate Probands in Guatemala

INTRODUCTION: Nonsyndromic cleft lip and palate (NCLP) anomalies are caused by interactions of genetic and environmental factors. Genealogical analysis is the best approach to determine, whether genetic factors are involved and, if yes, how they participate in etiology. Only a detailed analysis of a sufficient number of pedigrees collected in a given population makes it possible to calculate values of risk of recurrence (RR) and to estimate proportions of genetic and environmental factors involved in etiology. By this means, the information needed for genetic counseling can be obtained.

OBJECTIVES: To determine RR values for siblings of probands affected with NCLP in Guatemalan population that can be applied for a proper genetic counseling of families with a proband affected with this anomaly.

MATERIALS AND METHODS: We studied 141 probands with at least three-generation pedigrees. All data were collected during Rotaplast medical missions in Guatemala City and Antigua, Guatemala, during the years 2003-2005. Personal interviews were conducted with mothers of probands using the General Genetic Questionnaire. The RR of NCLP for siblings was calculated using the CONFIG software.

RESULTS: The RR figures for siblings of probands were: 2.99 (95% CI = 1.32-6.32) for siblings without distinguishing brothers and sisters; 3.57 (95% CI = 1.15-9.43) for brothers and 2.46 (95% CI = 6.37-7.56) for sisters. Brothers of probands had a higher risk of NCLP than sisters of probands.

CONCLUSION: Our results indicate that RR values for siblings of probands follow the same trend, as it has been seen in other populations. Further studies with a larger sample of pedigrees should be conducted to calculate RR for subgroups by sex of the proband and of the individual at risk, and by severity of the proband's cleft.

ACKNOWLEDGEMENT: The fieldwork for this study was supported by Rotaplast International, Inc.