Novel mutations in patients with X-linked Alport syndrome: Two case reports

RATIONALE: A genotype-phenotype correlation is known to be associated with Alport syndrome (AS). Identifying novel mutations can expand the knowledge about the natural course of AS. PATIENT CONCERNS: The first patient was a-15-year-old boy detected with proteinuria during the school health check-up. The second case was a-29-year-old woman, who visited the outpatient clinic for edema. DIAGNOSIS: We performed targeted next-generation sequencing to identify the mutations associated with AS. Results were confirmed by Sanger sequencing and multiplex ligation-dependent probe amplification. Missense mutation (c.2332G>C, p.Gly778Arg) was identified in the first case and an exon 16 deletion was also identified in the second case. INTERVENTION: We treated both cases with angiotensin receptor blocker (ARB). OUTCOMES: The amount of proteinuria in the first case did not change after ARB therapy, during the follow-up period (1 year). Proteinuria in the woman decreased to half of the baseline level, 1 year after treatment. Glomerular filtration rate was also maintained during the follow-up. CONCLUSION: We identified novel mutations in Koreans with an X-linked AS mutation in the COL4A5 gene and an individual phenotype. This is the first report of AS patients with a novel missense mutation and copy number variation.