Table 1.
CLD Mutations in the LCT Gene and Observed Lactase Activities of Duodenal Biopsy Specimens
| DNA Mutation | Protein Mutation | Exon | Patient | Mean LactaseProtein Activity(U/g of Protein) | Genotype |
| c.4170T→A | Y1390X | 9 | 1–13, 15, 18–26, 28–31 | 2.1 (range 0–7)a | Homozygote |
| c.4998_5001delTGAG | S1666fsX1722 | 14 | 17, 32 | 5 (range 3–7) | Compound heterozygoteb |
| c.653_654delCT | S218fsX224 | 2 | 16 | 2 | Compound heterozygoteb |
| c.804G→C | Q268H | 3 | 27 | 5 | Compound heterozygoteb |
| c.4087G→A | G1363S | 9 | 14 | 3 | Compound heterozygoteb |
a
Lactase activities of patients 11, 18, 20, 26, and 29 were not available.
b
Compound heterozygote for Y1390X.