Mutational Analysis of TYR, OCA2, SLC45A2, and TYRP1 Genes Identifies Novel and Reported Mutations in Chinese Families with Oculocutaneous Albinism

Objective center dot This study aims to investigate the main types of oculocutaneous albinism (OCA) and the distribution characteristics of mutations in the Chinese population. Additionally, genetic diagnosis and prenatal diagnosis were conducted for Chinese OCA families. Methods center dot A total of 116 blood DNA samples were collected from 40 unrelated families with suspected albinism. OCA gene testing and mutation screening were performed to identify mutated genes and genotypes. The prenatal genetic diagnosis was conducted on 20 fetal DNA samples (17 amniotic fluid DNA samples, 2 villus DNA samples, and 1 umbilical cord blood DNA sample). Follow-up was conducted on the born fetuses, and the feasibility and accuracy of prenatal genetic diagnosis were assessed based on the clinical phenotype of the fetuses. Results center dot Analysis of 40 pedigrees led to a molecular diagnosis for the patients or their parents: 24 (60%) had OCA1, 12 (30%) had OCA2, 1 (2.5%) had OCA3, and 2 (5%) had OCA4. Furthermore, 2.5% of the patients harbored only one heterozygous mutation in OCA2. The most common form of albinism observed was OCA1, followed by OCA2, OCA4, and OCA3. Prenatal diagnosis was performed on 20 fetuses, and the clinical phenotype of the fetuses aligned with the predictions of prenatal genetic diagnosis after follow-up. Conclusions center dot The results of gene mutation analysis in 40 families with oculocutaneous albinism indicate that OCA1 is the predominant type of albinism in the Chinese population, with all four types of OCA identified. Further research is needed to expand the understanding of pathogenic mutations associated with different types of OCA. Prenatal genetic testing, based on determining the albinism type and genotype of the proband and their parents, proves to be the most accurate and least traumatic method in eugenics. This study provides valuable insights into identifying novel therapeutic targets.