Catching Alport Syndrome Early Through Universal Age-3 Urine Screening

Kobe University researchers highlight the value of early urinalysis for detecting a rare genetic kidney disease

A study from Kobe University has revealed that Japan’s universal urine screening program for 3-year-olds may play a critical role in the early detection of Alport syndrome, a rare genetic disorder that leads to kidney failure, hearing loss, and vision changes.

The research, published in Kidney International Reports, shows that over 30% of Alport syndrome cases in children were first detected through age-3 urinalysis—and that 60% of these children already required medical treatment at the time of diagnosis.

Understanding Alport Syndrome

Alport syndrome affects approximately one in 5,000 people worldwide. It is caused by mutations in genes responsible for producing type IV collagen, a key protein that supports the structure of the kidney’s filtering units.

The condition leads to progressive kidney failure, and can also cause hearing and vision problems. While medications can delay kidney damage, they are most effective when treatment begins early—often before symptoms appear. Unfortunately, many patients are only diagnosed after kidney dysfunction has already developed.

Japan’s Screening System Offers a Head Start

“Japan conducts universal urinalysis screening at age 3, but no large-scale studies have been conducted to evaluate its effectiveness at identifying Alport syndrome in children,” said ISHIMORI Shingo, a pediatrician at Kobe University and lead author of the study.

To assess its value, Dr. Ishimori and his team reviewed medical records of 356 patients aged 18 and younger who were diagnosed with Alport syndrome at Kobe University Hospital. They analyzed how and when each patient’s condition was first identified.

Their findings show that 113 patients (about one-third) were referred to the hospital for testing because of abnormal results from the age-3 urine screening—making it the most common path to diagnosis. Moreover, 60% of these children had already reached the threshold for therapeutic intervention.

“Our study revealed that a remarkably high proportion of 3-year-old children with Alport syndrome already required therapeutic intervention even though they were still asymptomatic,” said Ishimori. “Consequently, the introduction of a urine testing system may allow for intervention before the onset of kidney dysfunction.”

Evaluating the Broader Effectiveness

While the study underscores the potential of early-age urinalysis, the researchers caution that it does not yet determine how effective the system is at identifying all cases of Alport syndrome across Japan.

The team estimates that about 23 million Japanese children underwent urine screening during the study period, but the proportion correctly diagnosed with Alport syndrome remains unknown.

“Future investigations should assess the diagnostic yield of the current approach,” Ishimori explained. “But we now know that implementing a screening system that facilitates early detection and enables early intervention might offer considerable benefits.”

These benefits include improved long-term outcomes for patients and reduced healthcare costs, as early treatment can prevent or delay end-stage kidney failure, dialysis, and transplantation.

A Call for Wider Adoption

“Since many countries do not have universal urinalysis screening at the age of 3, and not even all municipalities in Japan conduct the relevant tests for Alport syndrome, our findings should promote the wider adoption of measures leading to earlier detection and earlier treatment,” Ishimori concluded.

Funding

This research was supported by the Japan Society for the Promotion of Science (grant 23K07698), Health, Labour and Welfare Sciences Research Grants (grant 23FC1047), and the Japan Agency for Medical Research and Development (grants 24015773, 22810094, 23ek0109617s1702).

About Kobe University

Founded in 1902, Kobe University is one of Japan’s leading comprehensive research universities, with around 16,000 students and 1,700 faculty across 11 faculties and 15 graduate schools. The university combines the social and natural sciences to foster innovation and produce global leaders dedicated to solving society’s challenges.

Summary

Alport syndrome is a genetic kidney disease affecting 1 in 5,000 people.
Japan’s age-3 urine screening is the most common way Alport syndrome is first detected.
30% of cases in the study were identified through urine screening.
60% of those diagnosed already met criteria for early treatment.
Universal screening may improve outcomes and lower healthcare costs.
Researchers call for wider adoption of early urinalysis programs in Japan and beyond.

Original Publication
Authors: Hideaki Kitakado, Shingo Ishimori, Shuhei Aoyama, Yuka Kimura, Yuta Inoki, Chika Ueda, Yu Tanaka, Tomoko Horinouchi, Tomohiko Yamamura, Nana Sakakibara, China Nagano and Kandai Nozu.
Journal: Kidney International Reports
DOI: 10.1016/j.ekir.2025.09.022
Method of Research: Data/statistical analysis
Subject of Research: People
Article Title: Impact of Age-3 Urine Screening on Diagnosis and Treatment Timing in Alport Syndrome
Article Publication Date: 23-Sep-2025