Forum for Nordic Dermato-Venereology Nr 3, 2018 | Page 24

Dissertation Epidemiology of Neurofibromatosis Type 1 in Finland: Incidence, Mortality, Pregnancies and Congenital Malformations J ussi L eppävirta Department of Dermatology and Allergology, University of Turku and Turku University Hospital, Turku, Finland. E-mail: [email protected]. Jussi Leppävirta, MD, Specialist in Dermatology and Allergology, University of Turku and Turku University Hospital, Turku, Finland, defended his PhD thesis on June 1 st , 2018. The opponent was Associate Professor Hannele Laivuori from University of Tampere, and custos was Professor Veli-Matti Kähäri University of Turku, Finland. The thesis was supervised by Dr. Sirkku Peltonen and Professor Juha Peltonen. The thesis can be found in: http://urn.fi/URN:ISBN:978-951-29-7261-6 Neurofibromatosis type 1 (NF1) is a dominantly inherited can- cer syndrome, which is caused by mutations in the NF1 gene. Because of the high mutation rate of the gene, approximately half of the patients have a new mutation, while none of the parents have the disorder. The incidence of NF1 is estimated to be approximately 1:3,000. The best-known symptoms of NF1 are neurofibromas on the skin, but NF1 is a multisystem disorder associated with a decreased overall survival and in- creased risk for pathologies such as cancer, learning difficulties, epilepsy and speech defects. While there are some previous epidemiological studies on NF1-associated pregnancies and mortality of NF1, data is very limited. No epidemiological data is reported on birth size or overall risk for congenital malformations in NF1. We have acquired a nationwide cohort of approximately 1,500 patients with a confirmed diagnosis for NF1, and 10 matched controls per NF1 patient were collected. The data was linked with administrative registers to study incidence, mortality, pregnancies, birth size and congenital malformations of NF1. We observed that the incidence of NF1 in Finland was approx- imately 1:2,000, which is higher than previously generally accepted. Mortality of NF1 was considerably higher than in the general population. Pregnancy duration was shortened by a fetus with NF1, and the risk for several pregnancy and delivery complications was increased among NF1 mothers. Birth weight was decreased by having a mother with NF1, while having NF1 present in the child increased it. The risk for congenital malformations was almost three-fold among NF1 children compared to matched controls. Fig. 1. Jussi Leppävirta defeneded his PhD thesis on June 1 st , 2018. The following main conclusions can be drawn on the basis of this study: • The incidence of NF1 is approximately 1:2,000, which is higher than previously generally accepted. The incidence of NF2 was in line with previous studies being approximately 1:39,000 in our study. (I) • NF1 increases mortality significantly. Especially, mortality among NF1 females aged less than 50 is considerably higher than in the general population. (I) • NF1 of the fetus slightly shortens pregnancy duration. While Our study highlights a wide spectrum of ailments that NF1 the shortening is clinically insignificant, it is noteworthy causes, and the results can be utilized when guidelines of because only little is known about the role that the fetus treatment and follow-up of NF1 are developed. plays on the timing of the delivery. (II) 86 Forum for Nord Derm Ven 2018, Vol. 23, No. 3