GCNT2 and phenylketonuria: The most prevalent recessive disorders (gene associated;carrier frequency) were: autosomal recessive deafness (GJB2;17.2%), Cohen syndrome (VPS13B; 4.5%), beta-thalassemia(HBB; 4.3%), citrin deficiency (SLC25A13;3.2%), cataract 13 with adult I phenotype (GCNT2; 3.74%), Joubertsyndrome (TMEM67; 2.6%), and phenylketonuria (PHA;2.5%) (Tran et al.,2021).