Certain Patients with Alport Syndrome at Risk for Hypertensive Disease, Study Finds

Patients with X-linked or autosomal recessive Alport syndrome are at risk for developing hypertensive disease, which may also worsen their disease symptoms, a study shows.

The study, “Increased microvascular disease in X-linked and autosomal recessive Alport syndrome: a case control cross sectional observational study,” was published in the journal Ophthalmic Genetics.

Alport syndrome is a genetic disease characterized by impaired production of collagen, the main protein that helps cells to stick together and ensures the functional structure of tissues and organs.

Patients with this disorder often develop renal problems, but they can also experience hearing and vision issues. They may develop additional complications due to increased blood pressure and damage to small blood vessels.

Researchers from the University of Melbourne reviewed the clinical records of 69 patients with Alport syndrome to evaluate the prevalence of microvascular/hypertensive disease in this population. The retrospective case-control observational study included 56 patients with confirmed X-linked Alport syndrome and 13 individuals with autosomal recessive disease, who were recruited for a period of more than 21 years, from 1993 to 2014.

Increased blood pressure was determined by damage to small blood vessels in a patient’s retina — a thin layer of tissue that lines the back of the eye. This condition is medically identified as microvascular retinopathy.

Researchers found that male patients with X-linked Alport syndrome had 8.3 times the risk of having microvascular retinopathy than age- and gender-matched healthy volunteers. Female patients were also found to be at risk, with 3.23 times higher chances of developing microvascular retinopathy. Changes to small blood vessels were found to be mainly generalized, with focal narrowing and nicks.

The patients often had to undergo kidney transplantation when they reached end-stage renal disease. Although the procedure can resolve some of the patients’ clinical symptoms, the team found that it had no impact on the incidence of microvascular retinopathy in patients with X-linked Alport syndrome. In fact, moderate retinopathy was as common after transplantation as it was before the operation.

Interestingly, the incidence of microvascular retinopathy was found to be correlated with the number of Alport features present in the patients.

Nearly all patients with autosomal recessive disease (92%) were found to have microvascular retinopathy. When compared with healthy individuals, this group was found to have 15.75 times the risk of developing microvascular retinopathy.

Overall, these findings suggest that blood pressure is “too high in many individuals with Alport syndrome,” the researchers wrote. Strategies that can help manage blood pressure levels “may further slow the rate of renal functional decline” in this population, as well as “reduce the prevalence and severity of microvascular disease.”