Congenital anomalies of the kidney and urinary tract make up 20–30% of prenatally detected anomalies, with a birth prevalence of about 3.8 per 1000, and are the leading cause of CKD in children. This Kidney International review focuses on the two commonest causes, kidney dysplasia or hypoplasia and lower urinary tract obstruction.
About a fifth of cases have a genetic basis, with HNF1B and PAX2 the notable monogenic causes and copy-number variants common in syndromic presentations. The authors identify who should be tested: severe or syndromic disease, familial dysplasia, bilateral dysplasia (often cystic), and adults with CKD or on kidney replacement without a clear cause. Kidney damage progresses slowly; the need for kidney replacement peaks in adolescence but starts on average around age 31. Patients also carry higher cardiovascular and metabolic risk, neurocognitive problems and a small excess of malignancy.
The practical shift is for adult nephrology. Many adults with 'unexplained' CKD started life with CAKUT, and a genetic diagnosis can explain extrarenal features — HNF1B, for example, is linked to diabetes, raised liver enzymes and low magnesium — guide family counselling and inform living-donor assessment. This is a narrative review rather than new data.
- Consider genetic testing in severe, syndromic, familial or bilateral kidney dysplasia.
- Consider CAKUT and genetic testing in young adults with unexplained CKD or kidney failure.
- Look for extrarenal clues to HNF1B disease: early diabetes, low magnesium and abnormal liver tests.
- Follow patients with CAKUT for life, managing blood pressure, proteinuria and cardiovascular risk.
- Use a genetic diagnosis to guide counselling of relatives and assessment of potential living donors.
Why it matters
A congenital cause, and its genetics, may be hiding behind 'unexplained' CKD in young adults.
Don't overread it
This is a narrative review; it does not report new outcome data on the benefit of genetic testing.
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