| Summary: | Albinism is a genetic disorder caused by mutation of the gen encode melanin
(the skin, hair, and eye pigments). Clinically, albinism is divided into 2 types, those
are Ocular Albinism (OA) and Oculocutaneous Albinism (OCA). One of the OCA
types is OCA4, caused by MATP gene mutation. Based on phenotype analysis on
recently research, 2 samples (E6 and E7) in Daerah Istimewa Yogyakarta (DIY) are
categorized as OCA2 or OCA4. Based on SSCP result of recent study, it has been
predicted that there are mutations. Those mutations are on the exon 3 and exon 5 of
MATP gene, however there was no further results about position and the type of
mutation. Therefore, sequence analysis especially on exon 3 and exon 5 MATP gene
are needed to determine the OCA type. The aim of this research is to determine the
type and mutation position in exon 3 and exon 5 MATP gene, to study the
relationship between mutatio n position with alteration of amino acid in MATP
protein, and to know the relationship between alteration of amino acid with the
secondary structure of MATP protein.
DNA was isolated from 2 blood samples of 2 individuals with albinism (E6
and E7). PCR amplification was performed to produce the exon 3 MATP gene of E6
individual and exon 5 MATP gene of E7 individual fragment. Then, the PCR product
was used as template for sequencing in the 1st Base Laboratory. Secondary structure
of MATP protein was predicted by Psipred analysis.
Sequencing results revealed that mutation in exon 3 MATP gene of E6
individual was not found, while mutation exon 5 MATP gene of E7 individual was
found. The mutation type and position on exon 5 MATP gene of E7 individual were
substitution of Guanin to Adenin on base number 1045 (c.1045G>A) and transvertion
of Cytosin to Guanin on base number 1122 (c.1122C>G). The c.1045G>A mutation
caused the alteration of amino acid number 349 (glysin to arginine) and c.1122C>G
mutation caused the alteration of amino acid number 374 (phenylalanine to leucine).
These two mutations are called by missense mutations. Based on Psipred analysis
revealed the alteration of secondary structure of MATP protein mutant.
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