Variability of expression of oral-facial-digital syndrome type I in 15 Saudi girls: Why is there a high rate of median cleft lip in the phenotype?

BACKGROUND

It is well known that the incidence of nonsyndromal cleft lip and palate varies greatly according to ancestry: 0.3 to 0.4 per 1000 live births in blacks, one in 1000 in Caucasians, and two in 1000 in Asians and individuals from the central province of Saudi Arabia. Median cleft lip is a variable feature in oral-facial-digital syndrome type I (OFD-I).

OBJECTIVE

To test the hypothesis that genetic factors may determine the lip phenotype in OFD-I patients.

METHODS

A study involving 15 Saudi girls (from the central province of Saudi Arabia) with OFD-I showed a high rate (93.3%) of median cleft lip and palate. This rate in OFD-I patients is known to range from 33% to 56% in Caucasians and also known to be very low in blacks. The authors compared the rate of median cleft lip with or without cleft palate in the Arabian series (93.3%) with the rate in Caucasians and blacks.

RESULTS

The difference in median cleft lip with or without cleft palate among the three groups was significant.

CONCLUSION

This supports the hypothesis that ancestral genetic factors may determine the lip phenotype in OFD-I patients.