Postzygotic HRAS and KRAS mutations cause nevus sebaceous and Schimmelpenning syndrome.
Nevus sebaceous is a common congenital cutaneous malformation. Affected individuals may develop benign and malignant secondary tumors in the nevi during life. Schimmelpenning syndrome is characterized by the association of nevus sebaceous with extracutaneous abnormalities. We report that of 65 sebaceous nevi studied, 62 (95%) had mutations in the HRAS gene and 3 (5%) had mutations in the KRAS gene. The HRAS c.37G>C mutation, which results in a p.Gly13Arg substitution, was present in 91% of lesions. Nonlesional tissues from 18 individuals had a wild-type sequence, confirming genetic mosaicism. The HRAS c.37G>C mutation was also found in 8 of 8 associated secondary tumors. Mosaicism for HRAS c.37G>C and KRAS c.35G>A mutations was found in two individuals with Schimmelpenning syndrome. Functional analysis of HRAS c.37G>C mutant cells showed constitutive activation of the MAPK and PI3K-Akt signaling pathways. Our results indicate that nevus sebaceous and Schimmelpenning syndrome are caused by postzygotic HRAS and KRAS mutations. These mutations may predispose individuals to the development of secondary tumors in nevus sebaceous.
Department of Dermatology, University of Regensburg, Regensburg, Germany.
Leopold
L
Groesser
Eva
E
Herschberger
Arno
A
Ruetten
Claudia
C
Ruivenkamp
Enrico
E
Lopriore
Markus
M
Zutt
Thomas
T
Langmann
Sebastian
S
Singer
Laura
L
Klingseisen
Wulf
W
Schneider-Brachert
Agusti
A
Toll
Francisco X
FX
Real
Michael
M
Landthaler
Christian
C
Hafner
D000015:Abnormalities, Multiple / Q000235:genetics; D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics; D009030:Mosaicism; D009154:Mutation; D009506:Nevus / Q000235:genetics; D054000:Nevus, Sebaceous of Jadassohn / Q000235:genetics*; D019869:Phosphatidylinositol 3-Kinases / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras) / Q000235:genetics*; D015398:Signal Transduction; D055815:Young Adult; D018631:ras Proteins / Q000235:genetics*
C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D020929:Mitogen-Activated Protein Kinase Kinases; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins