40 families at high risk for autosomal recessive diseases, including 13 MMA families, 12 β-thalassemia families, 8 PKU families, 5 α-thalassemia families, 1 ARPKD family and 1 DFNB1A family caused by pathogenic variants of GJB2 gene were recruited. This evidence concerns the gene GJB2 and phenylketonuria.