Frequency of LCT-13910C/T and LCT-22018G/A single nucleotide polymorphisms associated with adult-type hypolactasia/lactase persistence among Israelis of different ethnic groups.

Primary lactase deficiency (PLD), the physiological decline of lactase, is associated with the LCT-13910C/T and LCT-22018G/A polymorphisms. PLD is the most common phenotype in humans and varies widely as a function of ethnicity. Israel is a multiethnic country. We analyzed the genetic frequencies of PLD in different Israeli ethnicities. Ethnicity-related frequencies were analyzed in 439 Israelis: Ashkenazi (n=96), Iraqi (n=96), Moroccan (n=96) Jews and Bedouin-Arabs (n=151). DNA was extracted from leukocytes; LCT-13910C/T, -22018G/A and -13915T/G (in Bedouin-Arabs) polymorphisms were analyzed by PCR-restriction fragment length polymorphism analysis. There was a significant association between ethnicity and genotype in both polymorphic LCT SNPs (-13910C/T and -22018). Prevalence of the CC (LCT-13910C/T) genotype associated with adult hypolactasia was 97%, 93%, 83% and 82% among Bedouin-Arabs and Iraqi, Ashkenazi and Moroccan Jews, respectively. The prevalence of the GG (LCT-22018G/A) adult hypolactasia genotype among those groups was identical to that of the CC genotype in each group, except for Iraqi-Jews, of which only 83% carried the GG genotype. The prevalence of heterozygous and homozygous genotypes associated with lactase persistence (CT, TT for -13910C/T and GA, AA for -22018G/A) was 3%, 7%, 17% and 18% and 3%, 17%, 17% and 18% for Bedouin-Arabs, Ashkenazi, Iraqi and Moroccan Jews, respectively. A significant correlation between SNPs was found. PLD prevalence is high among different ethnic groups in Israel and varies between ethnicities. The prevalence of the -13915*G allele, indicative of lactose persistence in African and Arab populations, was 41% in the Bedouin-Arabs group. Lactase persistence genotype prevalence was found to vary between Israeli ethnicities (4-18%). SNPs (-13910C/T and -22018) showed significant correlation in detecting genotype prevalence in Israeli Jews. We suggest adjusting nutritional recommendations accordingly.