COL4A3 and Alport syndrome: Of 91,000 pregnant people screened by a commercial laboratory, the observed carrier frequency for a P/LP variant was one in 279 for COL4A3, one in 332 for COL4A4, and one in 3055 for COL4A5, giving an overall carrier rate of one in 144 for any one of the Alport syndrome genes (Souter et al., 2023).