Pronounced linear calcinosis in a boy with mild dermatomyositis. A further possible example of superimposed segmental manifestation of a polygenic disorder.
A pronounced linear eruption with ulcerations and calcium extrusion present in a boy with a mild generalized rash clinically consistent with juvenile dermatomyositis or overlap syndrome is reported. Loss of heterozygosity (LOH) is a postzygotic mechanism by which a heterozygous somatic cell may become homozygous or hemizygous at a given gene locus. Such a mechanism can be suspected when a pronounced segmental manifestation of an acquired skin condition with a polygenic background is found to be superimposed on more or less symmetrically distributed nonsegmental lesions of the same disorder. Alternatively, such a segmental manifestation may reflect heterozygosity for a postzygotic mutation involving an additional gene locus. The severe linear lesions in our patient showed a Blaschko-linear arrangement and were superimposed on mild nonsegmental lesions of either amyopathic dermatomyositis or overlap syndrome. Either LOH or a postzygotic mutation at an additional gene locus may explain the pronounced linear involvement.
Boente
María del Carmen
Mdel C
Department of Dermatology, Hospital del Niño Jesús, Tucumán, Argentina. mboente@arnet.com.ar
Nadra
Graciela
G
Asial
Raúl
R
Happle
Rudolf
R
D001707:Biopsy, Needle; D002114:Calcinosis / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D002648:Child; D003078:Colchicine / Q000627:therapeutic use; D003882:Dermatomyositis / Q000188:drug therapy / Q000235:genetics / Q000473:pathology*; D018450:Disease Progression; D004359:Drug Therapy, Combination; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D006886:Hydroxychloroquine / Q000627:therapeutic use; D007150:Immunohistochemistry; D008297:Male; D018570:Risk Assessment; D012720:Severity of Illness Index; D012873:Skin Diseases, Genetic / Q000188:drug therapy / Q000473:pathology*; D016896:Treatment Outcome
D006886:Hydroxychloroquine; D003078:Colchicine