Impact of Age-3 Urine Screening on Diagnosis and Treatment Timing in Alport Syndrome

Area of Science:

• Nephrology
• Genetics
• Pediatrics

Background:

• Alport syndrome is a genetic kidney disorder caused by COL4A3/4/5 gene variants, often leading to end-stage kidney disease (ESKD).
• Early identification and treatment with renin-angiotensin system inhibitors (RAS-I) are crucial for slowing disease progression.
• Public urine screening at age 3 is implemented in Japan for early detection of potential kidney issues.

Purpose of the Study:

• To evaluate the role of age-3 urine screening in diagnosing Alport syndrome in children.
• To assess the clinical and genetic characteristics of diagnosed patients.
• To determine the proportion of patients eligible for RAS-I treatment at the time of initial urine screening.

Main Methods:

• Retrospective study of 356 pediatric patients diagnosed with Alport syndrome (August 2015 - May 2024).
• Analysis of clinical data, genetic variants (X-linked, autosomal dominant, autosomal recessive), and detection circumstances.
• Focus on the contribution of age-3 urine screening to initial diagnosis.

Main Results:

• Age-3 urine screening was the most common method for initial detection of urine abnormalities in 31.7% of patients.
• The most frequent forms were X-linked female (43.3%), X-linked male (30.1%), autosomal dominant (19.5%), and autosomal recessive (6.2%).
• Over 60% of patients diagnosed via screening were already eligible for RAS-I treatment.

Conclusions:

• Approximately 30% of Alport syndrome patients can be identified through age-3 urine screening.
• Early diagnosis via urine screening facilitates timely initiation of RAS-I therapy.
• Age-3 urine screening represents an effective strategy to potentially delay ESKD progression in Alport syndrome patients.