Angiotensin-converting enzyme gene polymophism in adult primary focal segmental glomerulosclerosis

BACKGROUND: Primary focal segmental glomerulosclerosis (FSGS) accounts for a third of biopsy-proven primary glomerulonephritis in Malaysia. Pediatric studies have found the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene to be associated with renal disease progression. The aim of this study was to determine the prevalence of the ACE (I/D) genotypes in adult primary FSGS and its association with renal outcome on follow-up.

METHODS: Prospective observational study involving primary FSGS patients was conducted. Biochemical and urine tests at the time of study were compared to the time of the diagnosis and disease progression analyzed. ACE gene polymorphism was identified using polymerase chain reaction amplification technique and categorized into II, ID and DD genotypes.

RESULTS: Forty-five patients with a median follow-up of 3.8 years (interquartile range: 1.8 - 5.6) were recruited. The commonest genotype was II (n = 23, 51.1%) followed by ID (n = 19, 42.2%) and DD (n = 3, 6.7%). The baseline characteristics were comparable between the II and non-II groups at diagnosis and at study recruitment except that the median urine protein-creatinine index was significantly lower in the II group compared to the non-II group (0.02 vs. 0.04 g/mmol (P = 0.03). Regardless of genotypes, all parameters of renal outcome improved after treatment.

CONCLUSION: The II followed by ID genotypes were the predominant ACE gene alleles in our FSGS. Although the D allele has been reported to have a negative impact on renal outcome, treatment appeared to be more important than genotype in preserving renal function in this cohort.