Higher prevalence of OCA1 in an ethnic group of eastern India is due to a founder mutation in the tyrosinase gene

Moumita Chaki, Arijit Mukhopadhyay, Shamba Chatterjee, Madhusudan Das, Swapan Samanta, Kunal Ray

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Purpose: Oculocutaneous albinism (OCA) is a group of autosomal recessive disorders characterized by deficient synthesis of melanin pigment and associated with common developmental abnormalities of the eye. It is one of the major causes of childhood blindness in India. The disease is common among an ethnic group (Tili) of Eastern India, which represents about 12.56% of the Bankura district population (approximately 0.4 million) of West Bengal. The purpose of the study was to investigate the molecular lesions causing OCA within this ethnic group for the unequivocal diagnosis of the carriers and attempt to decipher the cause for the high prevalence of OCA. Methods: Fourteen OCA-affected Tili families consisting a total of 161 individuals, including 26 patients, were recruited for the study. A lack of tyrosinase (TYR) activity among all the patients was ascertained by the tyrosinase hair bulb assay. Mutation screening in the tyrosinase gene (TYR) was done by single strand conformational polymorphism (SSCP) and DNA sequencing. The restriction fragment length polymorphism (RFLP) assay was carried out to determine the frequency of the pathogenic changes among the normal individuals. Haplotype analysis was performed at the TYR locus using a set of informative microsatellite and SNP markers. Results: All the patients were homozygous for a null mutation (c.832C>T, Arg278stop) in TYR exon 2, which might cause a complete loss of enzyme activity. The mutation occurred in the same haplotype background. The frequency of the disease in this ethnic group was estimated to be significantly higher than the world average. Conclusions: OCA1 in the Tili population is due to the occurrence of a founder mutation in the TYR as indicated by haplotype analysis. Higher prevalence of the mutation in the population group is due to marriage within the same community. The diagnostic RFLP assay can be utilized for genetic counseling and thereby will help to reduce the disease load on the population.

Original languageEnglish (US)
Pages (from-to)531-534
Number of pages4
JournalMolecular Vision
Volume11
StatePublished - Jul 19 2005

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Monophenol Monooxygenase
Oculocutaneous Albinism
Ethnic Groups
India
Mutation
Haplotypes
Genes
Restriction Fragment Length Polymorphisms
Eye Abnormalities
Population
Melanins
Genetic Counseling
Blindness
Marriage
DNA Sequence Analysis
Population Groups
Microsatellite Repeats
Hair
Single Nucleotide Polymorphism
Exons

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Chaki, M., Mukhopadhyay, A., Chatterjee, S., Das, M., Samanta, S., & Ray, K. (2005). Higher prevalence of OCA1 in an ethnic group of eastern India is due to a founder mutation in the tyrosinase gene. Molecular Vision, 11, 531-534.

Higher prevalence of OCA1 in an ethnic group of eastern India is due to a founder mutation in the tyrosinase gene. / Chaki, Moumita; Mukhopadhyay, Arijit; Chatterjee, Shamba; Das, Madhusudan; Samanta, Swapan; Ray, Kunal.

In: Molecular Vision, Vol. 11, 19.07.2005, p. 531-534.

Research output: Contribution to journalArticle

Chaki, M, Mukhopadhyay, A, Chatterjee, S, Das, M, Samanta, S & Ray, K 2005, 'Higher prevalence of OCA1 in an ethnic group of eastern India is due to a founder mutation in the tyrosinase gene', Molecular Vision, vol. 11, pp. 531-534.
Chaki M, Mukhopadhyay A, Chatterjee S, Das M, Samanta S, Ray K. Higher prevalence of OCA1 in an ethnic group of eastern India is due to a founder mutation in the tyrosinase gene. Molecular Vision. 2005 Jul 19;11:531-534.
Chaki, Moumita ; Mukhopadhyay, Arijit ; Chatterjee, Shamba ; Das, Madhusudan ; Samanta, Swapan ; Ray, Kunal. / Higher prevalence of OCA1 in an ethnic group of eastern India is due to a founder mutation in the tyrosinase gene. In: Molecular Vision. 2005 ; Vol. 11. pp. 531-534.
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abstract = "Purpose: Oculocutaneous albinism (OCA) is a group of autosomal recessive disorders characterized by deficient synthesis of melanin pigment and associated with common developmental abnormalities of the eye. It is one of the major causes of childhood blindness in India. The disease is common among an ethnic group (Tili) of Eastern India, which represents about 12.56{\%} of the Bankura district population (approximately 0.4 million) of West Bengal. The purpose of the study was to investigate the molecular lesions causing OCA within this ethnic group for the unequivocal diagnosis of the carriers and attempt to decipher the cause for the high prevalence of OCA. Methods: Fourteen OCA-affected Tili families consisting a total of 161 individuals, including 26 patients, were recruited for the study. A lack of tyrosinase (TYR) activity among all the patients was ascertained by the tyrosinase hair bulb assay. Mutation screening in the tyrosinase gene (TYR) was done by single strand conformational polymorphism (SSCP) and DNA sequencing. The restriction fragment length polymorphism (RFLP) assay was carried out to determine the frequency of the pathogenic changes among the normal individuals. Haplotype analysis was performed at the TYR locus using a set of informative microsatellite and SNP markers. Results: All the patients were homozygous for a null mutation (c.832C>T, Arg278stop) in TYR exon 2, which might cause a complete loss of enzyme activity. The mutation occurred in the same haplotype background. The frequency of the disease in this ethnic group was estimated to be significantly higher than the world average. Conclusions: OCA1 in the Tili population is due to the occurrence of a founder mutation in the TYR as indicated by haplotype analysis. Higher prevalence of the mutation in the population group is due to marriage within the same community. The diagnostic RFLP assay can be utilized for genetic counseling and thereby will help to reduce the disease load on the population.",
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AU - Das, Madhusudan

AU - Samanta, Swapan

AU - Ray, Kunal

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N2 - Purpose: Oculocutaneous albinism (OCA) is a group of autosomal recessive disorders characterized by deficient synthesis of melanin pigment and associated with common developmental abnormalities of the eye. It is one of the major causes of childhood blindness in India. The disease is common among an ethnic group (Tili) of Eastern India, which represents about 12.56% of the Bankura district population (approximately 0.4 million) of West Bengal. The purpose of the study was to investigate the molecular lesions causing OCA within this ethnic group for the unequivocal diagnosis of the carriers and attempt to decipher the cause for the high prevalence of OCA. Methods: Fourteen OCA-affected Tili families consisting a total of 161 individuals, including 26 patients, were recruited for the study. A lack of tyrosinase (TYR) activity among all the patients was ascertained by the tyrosinase hair bulb assay. Mutation screening in the tyrosinase gene (TYR) was done by single strand conformational polymorphism (SSCP) and DNA sequencing. The restriction fragment length polymorphism (RFLP) assay was carried out to determine the frequency of the pathogenic changes among the normal individuals. Haplotype analysis was performed at the TYR locus using a set of informative microsatellite and SNP markers. Results: All the patients were homozygous for a null mutation (c.832C>T, Arg278stop) in TYR exon 2, which might cause a complete loss of enzyme activity. The mutation occurred in the same haplotype background. The frequency of the disease in this ethnic group was estimated to be significantly higher than the world average. Conclusions: OCA1 in the Tili population is due to the occurrence of a founder mutation in the TYR as indicated by haplotype analysis. Higher prevalence of the mutation in the population group is due to marriage within the same community. The diagnostic RFLP assay can be utilized for genetic counseling and thereby will help to reduce the disease load on the population.

AB - Purpose: Oculocutaneous albinism (OCA) is a group of autosomal recessive disorders characterized by deficient synthesis of melanin pigment and associated with common developmental abnormalities of the eye. It is one of the major causes of childhood blindness in India. The disease is common among an ethnic group (Tili) of Eastern India, which represents about 12.56% of the Bankura district population (approximately 0.4 million) of West Bengal. The purpose of the study was to investigate the molecular lesions causing OCA within this ethnic group for the unequivocal diagnosis of the carriers and attempt to decipher the cause for the high prevalence of OCA. Methods: Fourteen OCA-affected Tili families consisting a total of 161 individuals, including 26 patients, were recruited for the study. A lack of tyrosinase (TYR) activity among all the patients was ascertained by the tyrosinase hair bulb assay. Mutation screening in the tyrosinase gene (TYR) was done by single strand conformational polymorphism (SSCP) and DNA sequencing. The restriction fragment length polymorphism (RFLP) assay was carried out to determine the frequency of the pathogenic changes among the normal individuals. Haplotype analysis was performed at the TYR locus using a set of informative microsatellite and SNP markers. Results: All the patients were homozygous for a null mutation (c.832C>T, Arg278stop) in TYR exon 2, which might cause a complete loss of enzyme activity. The mutation occurred in the same haplotype background. The frequency of the disease in this ethnic group was estimated to be significantly higher than the world average. Conclusions: OCA1 in the Tili population is due to the occurrence of a founder mutation in the TYR as indicated by haplotype analysis. Higher prevalence of the mutation in the population group is due to marriage within the same community. The diagnostic RFLP assay can be utilized for genetic counseling and thereby will help to reduce the disease load on the population.

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