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Genetics of risk factors for melanoma: an adult twin study of nevi and freckles.
J Natl Cancer Inst 2000; 92(6):457-63JNCI

Abstract

BACKGROUND

We sought by use of an adult twin study to investigate the relative contribution of genetic and environmental effects on the expression of nevi and freckles, which are known risk factors for melanoma, and to determine if age and sun exposure influence the heritability of nevi.

DESIGN AND METHODS

Total nevus and freckle counts were conducted on 127 monozygotic twin pairs and 323 dizygotic twin pairs. Intraclass correlations were calculated by use of analysis of variance. Model-fitting analyses were performed to quantify the genetic and environmental components of the variance for nevus and freckle counts.

RESULTS

The intraclass correlation for total nevus counts was.83 in monozygotic pairs compared with.51 in dizygotic pairs. Quantitative genetic analyses showed that the contribution of genetic factors on nevi expression varied according to age. For twins less than 45 years old, the additive genetic variance on total nevus count was 36% (95% confidence interval [CI] = 0.8%-63%), with 38% (95% CI = 14%-61%) and 26% (95% CI = 16%-42%) of the remaining variance attributed to common environment and unique environmental effects, respectively. In twins aged 45 years or older, common environmental effects on total nevus count became negligible, with the additive genetic variance increasing to 84% (95% CI = 77%-88%). Body site was also found to affect the heritability estimates for nevus counts, with a statistically significant difference between sun-exposed and sun-protected sites. The polychoric correlation (i.e., the correlation in liability within twins for more than two categories) for total freckle counts was.91 in monozygotic twin pairs compared with.54 in dizygotic twin pairs. Additive genetic effects explained 91% (95% CI = 86%-94%) of the variance in freckle counts.

CONCLUSION

The contribution of genetic factors on the variance for total nevus counts increased with age, and sun exposure appears to influence the expression of nevi. The results of this study highlight the need to take into account the age and site of nevus counts for future genetic linkage or association studies in the search for new melanoma genes.

Authors+Show Affiliations

Dermatology Department and Imperial Cancer Research Fund (ICRF), Skin Tumour Laboratory, St. Bartholomew's and Royal London School of Medicine, U.K. v.bataille@icrf.icnet.ukNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Twin Study

Language

eng

PubMed ID

10716963

Citation

Bataille, V, et al. "Genetics of Risk Factors for Melanoma: an Adult Twin Study of Nevi and Freckles." Journal of the National Cancer Institute, vol. 92, no. 6, 2000, pp. 457-63.
Bataille V, Snieder H, MacGregor AJ, et al. Genetics of risk factors for melanoma: an adult twin study of nevi and freckles. J Natl Cancer Inst. 2000;92(6):457-63.
Bataille, V., Snieder, H., MacGregor, A. J., Sasieni, P., & Spector, T. D. (2000). Genetics of risk factors for melanoma: an adult twin study of nevi and freckles. Journal of the National Cancer Institute, 92(6), pp. 457-63.
Bataille V, et al. Genetics of Risk Factors for Melanoma: an Adult Twin Study of Nevi and Freckles. J Natl Cancer Inst. 2000 Mar 15;92(6):457-63. PubMed PMID: 10716963.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Genetics of risk factors for melanoma: an adult twin study of nevi and freckles. AU - Bataille,V, AU - Snieder,H, AU - MacGregor,A J, AU - Sasieni,P, AU - Spector,T D, PY - 2000/3/16/pubmed PY - 2000/4/15/medline PY - 2000/3/16/entrez SP - 457 EP - 63 JF - Journal of the National Cancer Institute JO - J. Natl. Cancer Inst. VL - 92 IS - 6 N2 - BACKGROUND: We sought by use of an adult twin study to investigate the relative contribution of genetic and environmental effects on the expression of nevi and freckles, which are known risk factors for melanoma, and to determine if age and sun exposure influence the heritability of nevi. DESIGN AND METHODS: Total nevus and freckle counts were conducted on 127 monozygotic twin pairs and 323 dizygotic twin pairs. Intraclass correlations were calculated by use of analysis of variance. Model-fitting analyses were performed to quantify the genetic and environmental components of the variance for nevus and freckle counts. RESULTS: The intraclass correlation for total nevus counts was.83 in monozygotic pairs compared with.51 in dizygotic pairs. Quantitative genetic analyses showed that the contribution of genetic factors on nevi expression varied according to age. For twins less than 45 years old, the additive genetic variance on total nevus count was 36% (95% confidence interval [CI] = 0.8%-63%), with 38% (95% CI = 14%-61%) and 26% (95% CI = 16%-42%) of the remaining variance attributed to common environment and unique environmental effects, respectively. In twins aged 45 years or older, common environmental effects on total nevus count became negligible, with the additive genetic variance increasing to 84% (95% CI = 77%-88%). Body site was also found to affect the heritability estimates for nevus counts, with a statistically significant difference between sun-exposed and sun-protected sites. The polychoric correlation (i.e., the correlation in liability within twins for more than two categories) for total freckle counts was.91 in monozygotic twin pairs compared with.54 in dizygotic twin pairs. Additive genetic effects explained 91% (95% CI = 86%-94%) of the variance in freckle counts. CONCLUSION: The contribution of genetic factors on the variance for total nevus counts increased with age, and sun exposure appears to influence the expression of nevi. The results of this study highlight the need to take into account the age and site of nevus counts for future genetic linkage or association studies in the search for new melanoma genes. SN - 0027-8874 UR - https://www.unboundmedicine.com/medline/citation/10716963/Genetics_of_risk_factors_for_melanoma:_an_adult_twin_study_of_nevi_and_freckles_ L2 - https://academic.oup.com/jnci/article-lookup/doi/10.1093/jnci/92.6.457 DB - PRIME DP - Unbound Medicine ER -