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Advances in dermatology and venereology Acta Dermato-Venereologica
Striate Palmoplantar Keratoderma Showing Transgrediens in a Patient Harbouring Heterozygous Nonsense Mutations in Both DSG1 and SERPINB7
Ryo FUKAURA 1 , 2 , Takuya TAKEICHI 1 , Yusuke OKUNO 3 , 4 , Daiei KOJIMA 4 , Michihiro KONO 1 , Kazumitsu SUGIURA 5 , Yasushi SUGA 6 and Masashi AKIYAMA 1 * Departments of 1 Dermatology and 4 Pediatrics , Nagoya University Graduate School of Medicine , 65 Tsurumai-cho , Showa-ku , Nagoya 466- 8550 , Japan , 2 UCL Medical School , University College London , UK , 3 Center for Advanced Medicine and Clinical Research , Nagoya University Hospital , Nagoya , 5 Department of Dermatology , Fujita Health University School of Medicine , Toyoake , and 6 Department of Dermatology , Juntendo University Urayasu Hospital , Urayasu , Japan . * E-mail : makiyama @ med . nagoya-u . ac . jp Accepted Oct 26 , 2016 ; Epub ahead of print Oct 27 , 2016
Palmoplantar keratoderma ( PPK ) is a group of inherited skin disorders characterized by thickening of the skin on the palms and soles , often leading to pain . Classification has largely been clinical , but recently , causative genes for the various PPKs have been found , resulting in a need for a genetic classification of PPK ( 1 ). The most common type in the Japanese population is Nagashima-type PPK ( NPPK ) ( 2 ). This autosomal recessive condition is caused by a mutation in SERPINB7 . The SERPINB7 protein is found in the stratum corneum of the skin , and its main function is to regulate intercellular protease activity ( 3 ). The clinical features of NPPK include diffuse hyperkeratosis associated with erythema on the palms and soles and , in addition , on the dorsal aspects , known as transgrediens ( 2 ). Another type of PPK , striate PPK ( SPPK ), is autosomal dominant . The clinical features include strips of hyperkeratosis running longitudinally along the hands and fingers , and generalized hyperkeratosis on the soles of the feet . A mutation in any of 3 genes is reported to be an underlying cause : desmoglein 1 ( DSG1 ), desmoplakin ( DSP ) and keratin 1 ( KRT1 ) ( 4 ). Not only are these desmosomal proteins essential in maintaining the structure and integrity of the skin , but they are also essential to cell turnover ( 5 ). DSP mutations have been shown to increase skin proliferation , leading to hyperkeratosis , and the same effect has been predicted with DSG1 mutations ( 1 ), although the exact mechanism has not been fully clarified despite DSG1 being involved in various skin disorders ( 6 , 7 ). To date , there have been no reports of a patient with genetic mutations for 2 types of PPK . Here , we describe such a Japanese male .
CASE REPORT
A 36-year-old man presented with longstanding pain and hyperkeratotic palms . He had presented with corns on his palms in adolescence , which developed easily after sports . It was when he started working as a farmer that he noticed pain and “ stripe-like ” hyperkeratosis on his palms , and circular areas of hyperkeratosis on the soles ( Fig . 1A and B ). He also had abnormalities on the dorsal aspects of the hands : poorly demarcated areas of erythema and maceration ( Fig . 1C ). No lesions were found on the dorsa of the feet . Although there were no white spongy changes after water immersion , as has been reported for some cases of NPPK , his palms were abnormally moist and malodorous compared with a healthy subject . The stripe-like pattern of hyperkeratosis on this patient ’ s palms appeared to be a classical example of SPPK . However , the continuation of the lesions to the dorsal aspects , and a change in the lesions from hyperkeratosis to erythema were atypical . Instead , these seemed to resemble transgrediens reported in NPPK ( 2 ). Other than a sister who has atopic dermatitis , he has no family history of hyperkeratosis or other skin disorders .
Fig . 1 . Clinical and histological features of the patient . ( A ) Palms showing typical longitudinal hyperkeratotic lesions on the fingers . ( B ) Plantar aspects showing diffuse areas of hyperkeratosis . ( C ) Dorsal aspects of the hands , showing generalized erythema . ( D ) Pedigree of the family showing genotypes for the mutations in DSG1 and SERPINB7 . wt : wild type , het : heterozygote . ( E ) Skin biopsy sample from the sole shows keratohyalin granules of various sizes , and acantholysis . Scale bar : 100 µ m . ( F ) Electron microscopy clearly shows a highly electron-dense line . Magnification : × 20,000 .
This is an open access article under the CC BY-NC license . www . medicaljournals . se / acta Journal Compilation © 2017 Acta Dermato-Venereologica . doi : 10.2340 / 00015555-2553 Acta Derm Venereol 2017 ; 97 : 399 – 401