The Genotypes Of Non-syndromic Oculocutaneous Albinism

Backgrounds:Oculocutaneous albinism (OCA) is an autosomal recessive genetic disorders with the hereditary variation of melanin synthesis that results in a reduced or complete absence of melanin in the skin, hair, and eyes, often accompanying with eye disease, such as photophobia, strabismus, moderate to severe visual impairment, nystagmus, etc. OCA is one of the earliest studied genetic disease because the characteristics of the patients are more attractive in appearance. In Han Chinese, the incidence of OCA is about1:18000. OCA is high genetic heterogeneity. At least16genes have been found to be associated with OCA, which regulate the processes of melanin synthesis and distribution and can be classified into2groups:non-syndromic and syndromic. Non-syndromic OCA is subdivided into4subtypes (OCA1-4) based on genetic genes as follows:TYR, OCA2, TYRP1, SLC45A2. And the subtypes can only be differential diagnosised by genetic gene.Purpose:The purpose of the current research was to detect the underlying genetic defect in probands, and perform prenatal genetic diagnosis for them or their parents’ current pregnancy or re-pregnancy.Methods:According to the proportion of every subtype in our country, all the patients with clinical diagnosis were studied depending on Multiplex Ligation-dependent Probe Amplification (MLPA) and specific PCR sequencing analysis of TYR, OCA2, SLC45A2, TYRP1in turn.Results:9of11patients have detected two pathogenic mutations, and2patients have only one. There are16kinds mutations totally, which are13point-mutations,2insertion-mutations and1large-deletion mutation.6mutations have not been described previously. According to the pathogenic genes, there are5cases for OCA1,5cases for OCA2and1case for OCA4.Conclusion:MLPA is a highly sensitive and accurate detection method for large deletion/duplication. Combining direct sequencing with MPLA can detect OCA fast and accurately, which also increases the detection rate.