Cleft deformities in Singapore: a population-based series 1993-2002

Cleft deformities, though non-lethal, receive much attention from parents and doctors alike because of their obvious physical disfigurement, social stigma and associated feeding and vocal articulation problems. There is also an association with chromosomal defects for certain cleft deformities. The aim of this study is to examine the incidence, demographic data and epidemiological trend of this condition over a ten-year period, and to compare our data with other local studies, as well as to examine the chromosomal defects associated with this condition.

Data of cleft deformity cases born during the period 1993-2002 was retrieved from the National Birth Defects Registry and analysed.

There were a total of 859 cases of cleft deformities in the ten-year period 1993-2002, giving an overall incidence of 1.87 per 1,000 live births, with an increasing trend noted. Incidence was highest among the Chinese and lowest among the Indians. There were more males with cleft deformities compared with females. The risk of aneuploidy rose by about ten-fold in syndromic cleft cases, compared to non-syndromic cleft cases. There were two cases of Trisomy 21 in the non-syndromic cleft lip and palate group, giving an incidence of 1:133.

The race-specific and gender-specific differences in cleft incidence suggest genetic and environmental factors which warrant further studies. The increased risk of aneuploidy among syndromic clefts, as well as the finding of Trisomy 21 in non-syndromic cleft lip and palate cases suggest a need for karyotyping in these two groups of antenatally-diagnosed cleft deformities.