Pedigree Analysis Of Nonsyndromic Oculocutaneous Albinism In A Chinese Family And Genetic Diagnosis Of Albinism

Background Oculocutaneous albinism （OCA） is a common phenotype for aheterogeneous group of autosomal recessive genetic disorders. It is characterized byreduced or complete absent of melanin in the skin, hair follicle, and eyes, and which isassociated with the ocular features of photophobia, strabismus, moderate to severevisual impairment, nystagmus，iris transillumination，retinal pigmentary deficiency andmisrouting of optic nerve fibres. Non-syndromic OCA have been distinguished: OCA1,OCA2, OCA3, and OCA4, with recessive mutations in the TYR, OCA2, TYRP1andMATP genes respectively. According to the distribution of the achromasia and with orwithout other system disease, albinism have divided into three styles: ocular-albinism（OA）, oculocutaneous albinism （OCA）, and Hermanskv-Pudlak syndrome （HPS） orChediak-Higashi syndrome （CHS）. To date, more than400mutations of OCA gene havebeen identified in patients by the international albinism center. These mutations include273mutations of TYR,83mutations of OCA2,16mutations of TYRP1and45mutations of MATP respectively.Objective To analysis the pedigree and clinical characteristics of nonsyndromicoculocutaneous albinism in a chinese family and the sequencing result. Furtherdiscussed the genotype-phenotype correlation of OCA reported in Chinese Hanpopulation.Method All exons including intron-exon boundaries of TYR gene were amplified bypolymerase chain reaction（PCR） using specific primers, then the TYR gene was sequenced in a Chinese Han pedigree, meanwhile,676unrelated population matchedwere made. All reported papers about OCA mutations were reviewed and confirmed thegenotype-phenotype characteristics reported in Chinese Han population.Results The result of the sequencing analysis revealed that the proband was compoundheterozygous for c.832C>T and c.929₉30insC frame-shift mutation of the TYR gene.The proband’s father was heterozygous for the c.929₉30insC frame-shift mutation, andhis mother was heterozygous for c.832C>T mutation. The mutation was not found in676unrelated controls.Conclusion The nonsense mutation c.832C>T and c.929₉30insC frame-shift mutationseems to be the pathogenic mutation in the patient with OCA. It is concluded that thepatient was OCA1A by his clinical phenotype and genotype.