Gene variation analysis and prenatal diagnosis for 54 families with oculocutaneous albinism / 中华围产医学杂志

ABSTRACT

Objective:To investigate the pathogenic gene locus and prenatal genetic diagnosis of 54 families with oculocutaneous albinism (OCA).Methods:This retrospective study enrolled 54 OCA probands and their families from Gansu Province Maternal and Child Health Care Hospital from May 2014 to May 2020. TYR gene variation screening was performed on the probands by Sanger sequencing. Those with negative results were analyzed by high-throughput sequencing, and further verification was performed on their parents by Sanger sequencing. Among the 54 families, 15 ml amniotic fluid were collected from 16 women at 18-21 gestational weeks in their subsequent pregnancy. Sanger sequencing combined with short tandem repeats sequence for linkage analysis were performed for genetic analysis. All data were analyzed using descriptive statistical analysis. Results:Out of the 54 OCA probands, 48 were diagnosed as OCA1, five were OCA2 and one was OCA4 based on the Sanger sequencing and high-throughput sequencing detection. A total of 26 different variation sites were involved in the 48 OCA1 probands, including 15 missense mutations, five nonsense mutations, three splicing mutations, and three frame-shift mutations, among which, c.929insC (29%, 28/96) was the most frequent mutation, followed by c.896G>A (11%, 11/96), c.832C>T (8%, 8/96) and c.703T>C (5%, 5/96). The diagnosis was confirmed in all 16 fetuses in the 16 families that underwent prenatal diagnosis. Five of them were affected and their mothers chose to terminate the pregnancies, the other 11 pregnancies continued to delivery, including seven heterozygous carriers and four fetuses without the same pathogenic allele as the proband. Maternal contamination was excluded in all prenatal samples using short tandem repeat for linkage analysis. All 11 children were in good health during telephone follow-up one month after birth. Postnatal validations were consistent with the prenatal tests.Conclusions:Genetic diagnosis could accurately identify various types of OCA and help to provide prenatal diagnosis and fertility consultation for subsequent pregnancies.