A Seoul National University Bundang Hospital (SNUBH) research team found that the rare inherited kidney disease X-chromosome-associated Alport syndrome progresses to end-stage renal failure at around 50 years of age, even in women who develop the disease later than men.

Alport syndrome is a genetic abnormality of the glomerular basement membrane, which plays a key role in filtering waste from the kidneys. 

The syndrome is most often linked to the X chromosome.

Male patients who have the syndrome often progress to end-stage renal failure requiring dialysis or a kidney transplant at an average age of 25. 

Women, on the other hand, are known to maintain kidney function for a longer period of time before progressing to end-stage renal failure.

However, because symptoms appear later in women, awareness of the disease is significantly lower than that of men. Women are also often overlooked as carriers with only a genetic factor and no manifestation of the disease.

In addition, while the prognosis of X chromosome-associated Alport syndrome in males is well-understood and well-studied, the prognosis of females is not yet well-understood.

As a result, the team, led by Professor Kim Ji-hyun of the Department of Pediatrics, analyzed the prognosis of nephropathy in men and women according to three genotypes -- non-truncating group, the abnormal splicing group, and the truncating group -- in 216 patients diagnosed with Alport syndrome through genetic testing from 2000 to 2021 at 12 Korean institutions, including SNUBH.

Professors Cheong Hae-il at Red Cross Hospital and Kang Hee-Gyung and Ahn Yo-han at Seoul National University Hospital also participated in the study.

The results showed that Korean female Alport syndrome patients reached end-stage renal failure at a median age of 50 and had an overall worse prognosis compared to overseas studies.

This compares to end-stage renal failure in Korean men at a median age of 25, which was not significantly different from international studies.

In addition, the truncating genotype group, which had the worst prognosis in men, also had the worst prognosis in women, reaching end-stage renal failure at the earliest age.

The truncating genotype also had more severe symptoms, including the appearance of visible hematuria at an earlier age than the other genotypes.

"Early detection of Alport syndrome can help preserve kidney function and prolong life with blood pressure control medications," Professor Kim said. "Although it is considered a rare disease, recent advances in genetic testing have shown that it is more frequent than previously thought and is often undiagnosed or diagnosed late."

Therefore, the hospital recommends that people with a family history of chronic kidney failure, hematuria, or proteinuria, receive a test, she added.

The results of the research were published in Scientific Reports.