Pigmentation phenotype, photosensitivity and skin neoplasms in patients with myotonic dystrophy.
Recent studies have suggested a possible excess risk of skin neoplasms in patients with myotonic dystrophy (DM). Risk factors related to this observation have not been defined.



Information regarding personal history of skin tumors, pigmentation phenotype, and skin reaction to sun exposure were collected from 266 DM patients who were enrolled in the US National Institutes of Health National Registry of Myotonic Dystrophy and Facioscapulohumeral Muscular Dystrophy Patients and Family Members.



Seventy-seven subjects reported having skin tumors that were either benign (n = 31), malignant (n = 32) or both (n = 14). Female gender [odds ratio (OR) = 2.27, 95% confidence interval (CI) 1.02-5.05, P = 0.04], older age (OR = 1.10, 95% CI 1.05-1.16, P < 0.001) and DM1 subtype (OR = 3.42, 95% CI 1.27-9.26, P = 0.02) were associated with a malignant skin tumor. The associations between malignant skin tumors and known risk factors [light eye color (OR = 1.62, 95% CI 0.78-3.39, P = 0.20), light skin complexion (OR = 1.31, 95% CI 0.63-2.73, P = 0.48) and moderate/extensive face freckles (OR = 1.47, 95% CI 0.50-4.34, P = 0.49)] were modest. Strong, but not statistically significant, associations were noted with sunburn reactions when exposed to sunlight (OR = 4.28, 95% CI 0.91-19.95, P = 0.06, and OR = 2.19, 95% CI 0.67-7.09, P = 0.19, for sunburn with and without blistering, respectively).



Although our study was limited by small sample size, the risk factors for malignant skin tumors in DM strongly resemble the general population. It is recommended that DM patients adhere to sun exposure protective behavior.
Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, MD, USA.
S M
SM
Gadalla
Department of Neurology, Neuromuscular Disease Center, University of Rochester Medical Center, Rochester, NY, USA.
J E
JE
Hilbert
Department of Neurology, Neuromuscular Disease Center, University of Rochester Medical Center, Rochester, NY, USA.
W B
WB
Martens
Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, MD, USA.
S
S
Givens
Department of Neurology, Neuromuscular Disease Center, University of Rochester Medical Center, Rochester, NY, USA.
R T
RT
Moxley
Clinical Genetics Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, NIH, Bethesda, MD, USA.
M H
MH
Greene
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008548:Melanosis / Q000453:epidemiology*; D008875:Middle Aged; D009223:Myotonic Dystrophy / Q000453:epidemiology*; D010641:Phenotype; D012042:Registries; D012307:Risk Factors; D012878:Skin Neoplasms / Q000453:epidemiology*; D012880:Skin Pigmentation / Q000502:physiology*; D013471:Sunburn / Q000453:epidemiology*; D055815:Young Adult
cancer; myotonic dystrophy; repeat expansion size; risk factors; skin