Clinical and pathological features of pachyonychia congenita.
Pachyonychia congenita (PC) is a rare genodermatosis affecting the nails, skin, oral mucosae, larynx, hair, and teeth. Pathogenic mutations in keratins K6a or K16 are associated with the PC-1 phenotype whereas K6b and K17 mutations are associated with the PC-2 phenotype. Analysis of clinical, pathological, and genetic data from the literature and two research registries reveal that >97% of PC cases exhibit fingernail and toenail thickening, and painful plantar keratoderma. Prospective evaluation of 57 PC patients from 41 families revealed variable clinical findings: hyperhidrosis (79%), oral leukokeratosis (75%), follicular keratosis (65%), palmar keratoderma (60%), cutaneous cysts (35%), hoarseness or laryngeal involvement (16%), coarse or twisted hair (26%), early primary tooth loss (14%), and presence of natal or prenatal teeth (2%). Stratification of these data by keratin mutation confirmed the increased incidence of cyst formation and natal teeth among PC-2 patients, although cysts were more commonly seen in PC-1 than previously reported (25%-33%). Previously unreported clinical features of PC include development of painful oral and nipple lesions during breastfeeding, copious production of waxy material in ears, and inability to walk without an ambulatory aid (50%). Possible pathogenic mechanisms are discussed with respect to the clinicopathologic and genetic correlations observed.
Leachman
Sancy A
SA
Department of Dermatology, University of Utah Health Sciences Center, Salt Lake City, Utah 84112-5550, USA. sancy.leachman@hci.utah.edu
Kaspar
Roger L
RL
Fleckman
Philip
P
Florell
Scott R
SR
Smith
Frances J D
FJ
McLean
W H Irwin
WH
Lunny
Declan P
DP
Milstone
Leonard M
LM
van Steensel
Maurice A M
MA
Munro
Colin S
CS
O'Toole
Edel A
EA
Celebi
Julide T
JT
Kansky
Aleksej
A
Lane
E Birgitte
EB
D007644:Darier Disease / Q000151:congenital / Q000235:genetics / Q000473:pathology; D004476:Ectodermal Dysplasia / Q000235:genetics / Q000473:pathology*; D005260:Female; D005799:Genes, Dominant; D005838:Genotype; D006801:Humans; D007633:Keratins / Q000737:chemistry / Q000235:genetics; D007645:Keratoderma, Palmoplantar / Q000151:congenital / Q000235:genetics / Q000473:pathology*; D008297:Male; D009154:Mutation; D009264:Nails, Malformed / Q000151:congenital / Q000235:genetics / Q000473:pathology*; D010641:Phenotype
D007633:Keratins