Aims To investigate the association between sequence variants in the promoter region of the oestrogen receptor-α (ER-α) gene and the angiographic severity of coronary artery disease (CAD).

Methods and results We studied 503 subjects undergoing coronary angiography (mean age 63±12 years, 72% men, 28% women). Coronary artery disease extent was assessed by the number of: (1) major coronary vessels with >50% narrowing (NMCV); (2) coronary vessels with any narrowing (NCV); (3) narrowed coronary segments (NCS). The number of thymine and adenine dinucleotide repeats [(TA)_n], 1174 base-pairs upstream exon 1, was determined by PCR. The median number of (TA)_n(18) was used to categorize subjects into long, short and mixed allele genotypes. Poisson regression was used to analyse the association between genotypes and CAD extent, with age category (age ⩽55 vs >55), sex, risk factors and age at onset of CAD as covariates. In young subjects, (TA)_nlength had a significant effect on NCS (P=0.047) and a borderline significant effect on NCV (P=0.066). Young subjects homozygous for long alleles had higher NCV and NCS compared to those homozygous for short alleles (NCV 3.7±2.4 vs 2.4±1.8, NCS 4.4±2.7 vs 3.1±2.3, respectively, P⩽0.034).

Conclusion The (TA)_nlength in the ER-α gene promoter region is associated with the angiographic severity of CAD in young patients.