ABSTRACT
BACKGROUND: Genetic studies indicate that nonsyndromic cleft lip/palate (NSCLP) has the characteristics of a complex genetic trait. Reports from different authors have suggested several candidate genes mapping in different chromosome regions. Association studies have suggested that a clefting locus is located on chromosome 6p. On these grounds we have investigated the possible association between five microsatellite markers located on 6p22-25 and NSCLP. AIM: To test the hypothesis on the possible association of a clefting locus with microsatellite markers located in 6p22-25. PATIENTS AND METHODS: The sample consisted of 54 unrelated case-parent trios that comprise 54 NSCLP probands and 108 parents. Five microsatellite markers spanning the region 6p22-25 were analyzed for each individual by means of polymerase chain reaction with fluorescent labeled microsatellite markers. Electrophoresis of the PCR products was performed on a laser-fluorescent DNA sequencer. Nonparametric ETDT and MCETDT programs, were used to analyze the genotype data. RESULTS: The family based association study showed that for the genotype wise analysis, only D6S259 presented a significant p-value (0.03). Nevertheless no individual allele of this marker showed an evident preferential transmission from heterozygous parents to affected offspring. CONCLUSIONS: The results of the present study do not show a clear evidence that a candidate gene for NSCLP may be located within or near the analyzed chromosome region in our sample. Nevertheless, it must be emphasized that the genotype wise analysis shows a significant p-value for D6S259 marker.