Oculocutaneous albinism type 4: Novel compound heterozygous mutations in the SLC45A2 gene in a Chinese case

Background: Oculocutaneous albinism type 4 (OCA4) is a rare autosomal recessive disorder characterized by a reduction of pigmentation in skin, hair, and eyes, and OCA4 is mainly seen in the SLC45A2 gene variants.

Objective: To report a Chinese patient suspected of oculocutaneous albinism and identify the causing mutation.

Methods: Genomic DNA was extracted from the peripheral blood samples of the patient, his parents, and elder brother. Whole exome sequencing was performed in the family, and Sanger sequencing was then used to verify the mutations.

Results: Compound heterozygous variants, c.1304C>A (p.S435Y) and c.301C>G (p.R101G) in SLC45A2 gene, were detected in the proband, which were inherited from his father and mother respectively. Based on the ACMG guidelines, we can interpret the c.1304C>A (p.S435Y) variant as a suspected pathogenic variant and the c.301C>G (p.R101G) variant as a clinically significant unspecified variant. The diagnosis of OCA4 is confirmed.

Conclusion: We firstly reported this case of OCA4 with the compound heterozygous variants in the SLC45A2 gene. Our findings further enrich the reservoir of SLC45A2 mutations in OCA4.