Hypopigmentation, anomalous cerebral dominance and seasonality.

This paper proposes a prenatal seasonal hypopigmentation influence associated with anomalous cerebral dominance that occurs during the winter or early spring. A possible mechanism would be seasonal changes in sex hormone levels that affect the activation and inactivation of DNA by reversible methylation. The proposed prenatal seasonal hypopigmentation effect might be relevant to dyslexia, Prader-Willi syndrome, breast cancer, Alzheimer's and Parkinson's disease. Putative chromosomal loci associated with the proposed seasonal mechanism would be 15q11-13 (dyslexia and Prader-Willi syndrome), 21q region (breast cancer and Alzheimer's disease) and 19p region (pigmentation gene).