Familial acanthosis nigricans due to K650T FGFR3 mutation.
BACKGROUND
Acanthosis nigricans is a feature of several syndromes caused by activating mutations of the fibroblast growth factor receptor 3 gene (FGFR3), including Crouzon syndrome with acanthosis nigricans, thanatophoric dysplasia, and severe achondroplasia with developmental delay and acanthosis nigricans (SADDAN syndrome).


METHODS
We describe a healthy 4-year-old African American girl with generalized acanthosis nigricans since infancy. Her father had a history of acanthosis nigricans since childhood, in addition to Crohn disease, obesity, and adult-onset diabetes mellitus. A pedigree with numerous affected family members was constructed. Other than slightly short stature, no associated anomalies were found, including dysmorphic features or skeletal or neurologic defects. Genetic testing revealed a previously undescribed, heterozygous lysine to threonine mutation at codon 650 of the FGFR3 gene in the 4 affected family members who were tested.


CONCLUSIONS
Extensive acanthosis nigricans in early childhood, especially with a family history of acanthosis nigricans, may warrant testing for FGFR3 mutations.
Berk
David R
DR
Department of Internal Medicine, Washington University School of Medicine, 660 S Euclid, Campus Box 8123, St Louis, MO 63110, USA. DBerk@im.wustl.edu
Spector
Elaine B
EB
Bayliss
Susan J
SJ
D000052:Acanthosis Nigricans / Q000235:genetics* / Q000473:pathology; D000328:Adult; D044383:Black People; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D010375:Pedigree; D017354:Point Mutation; D051498:Receptor, Fibroblast Growth Factor, Type 3 / Q000235:genetics*; D001741:Black or African American
D051498:Receptor, Fibroblast Growth Factor, Type 3