Abstract
Purpose: :
To apply the importance of molecular genetic screening strategies in early carrier diagnosis for couples at risk of severe Oculocutaneous Albinism (OCA), due to prior generations.
Methods: :
Genomic DNA was extracted from EDTA coated peripheral blood sample. PCR reactions, automatic DNA sequence analysis were performed with five carrier families with probands to screen the coding and splice site regions of OCA candidate genes. Chromas software were used to analyze the sequence patterns.
Results: :
Case 1: One reported silent mutation c.1064G>A (p.Ala355Ala); one novel splice site variation (IVS12-4A>G); one novel heterozygous variation (IVS10-58C>T) were identified in OCA2/P gene.Case 2: One novel heterozygous missense mutation c.460G>A (p.Glu154Lys) were observed in OCA2/P gene. Father’s DNA showed wild type sequence pattern whereas Mother’s DNA showed heterozygosity for c.460G>A. Case 3: In this case, Mother has an ongoing pregnancy of 13 weeks and the diagnosis has not yet been confirmed in the index child during sample collection. Genetic analysis revealed two novel variations one synonymous change c.168G>A (p.Gln56Gln) and a stop codon c.324G>A (p.Trp108X) in heterozygose status on both of these parent samples. Two reported polymorphisms c.-301C>T; c.-199C>A were observed as heterozygose condition in mother’s sample alone. Both of these participants were showed a normal phenotype.Case 4: In Proband, two reported homozygous polymorphisms c.-301C>T and c.-199C>A were detected from promoter region. Molecular screening of parent DNA samples reveled heterozygous status of both these above variations. Case 5: Two reported polymorphisms c.-301C>T and c.-199C>A were observed as heterozygous condition in second generation couple. The parents were not interested for diagnosis of index child.
Conclusions: :
This is the first prospective study exploring informed decision-making for the participants. Therefore, it is crucial and provides a precious knowledge about the entire genetic profile of participated families and thus in future, enable to healthy generations.
Keywords: gene screening • genetics • mutations