Neonatal blue light phototherapy and melanocytic nevi: a twin study.

BACKGROUND: Neonatal blue light phototherapy (NBLP) has been widely and successfully used for the treatment of neonatal jaundice to reduce the plasma concentration of bilirubin and, hence, to prevent kernicterus. Only a few and controversial data are available in the literature as to how NBLP influences melanocytic nevus development. OBJECTIVE: Our goal was to conduct a twin study with the aim of better understanding the role of NBLP in melanocytic nevus development. We also investigated the roles of other environmental and constitutional factors in nevus formation. METHODS: Fifty-nine monozygotic and dizygotic twins were included in this cross-sectional study. One of the twin members received NBLP, and the other did not. A whole-body skin examination was performed to determine the density of melanocytic skin lesions. The prevalence of benign pigmented uveal lesions was evaluated during a detailed ophthalmologic examination. A standardized questionnaire was used to assess data relating to constitutional, sun-exposure, and other variables. To search for possible gene-environmental interactions involved in the appearance of pigmented lesions, the melanocortin 1 receptor variants and the I439V polymorphism of histidine ammonia-lyase genes were also determined in the enrolled twins. RESULTS: NBLP was associated with a significantly higher prevalence of both cutaneous and uveal melanocytic lesions. No association was found between the examined gene polymorphisms and the number of pigmented alterations in the examined study group. CONCLUSIONS: Our data suggest that NBLP could well be a risk factor for melanocytic nevus development. Phototherapy with blue-light lamps is a standard and essential therapeutic modality in neonatal care; therefore, additional in vivo and in vitro studies are necessary to establish its potential long-term adverse effects.

First detection of the melanoma-predisposing proline-48-threonine mutation of p16 in Hungarians: was there a common founder either in Italy or in Hungary?

The P48T germ line mutation of p16 was detected in a Hungarian multiple primary melanoma patient (deceased at the age of 39) with no affected family members. Genetic analysis of the patient and his family revealed that the patient was homozygous for the mutation, whereas his parents (father currently aged 69 and mother 63), who are free from any malignancies and atypical moles, are both heterozygous for the mutation. Our data suggest that the P48T mutation of p16 is a strong melanoma-predisposing factor, but the fact that the heterozygous mutant parents have not yet exhibited melanoma or atypical moles indicates that the penetrance of this allele might depend on modifying factors. The rare P48T germ line mutation of p16 has been reported previously in only four independent studies, all in patients with Italian ancestry. Here, we first report the inheritance of the rare P48T mutation of CDKN2A in a Hungarian family with a homozygous multiple primary melanoma member and unaffected heterozygous family members. The question of whether the mutation detected in Hungary is the result of an independent event, or migration of the founder mutation occurred at some time in the past, necessitates further investigations.