Abstract and Introduction
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Pachyonychia congenita (PC) is a rare form of hereditary palmoplantar keratoderma (PPK) (Smith et al., 2001) and is a genetic disorder of keratinization that affects the nails, skin (particularly palms and soles), oral mucosa and laryngeal mucosa, teeth, and hair (Karen & Schaffer, 2007; Liao et al., 2007; Smith et al., 2001; Strober, 2003). PC is in one of the four genes encoding keratin 6a, 6b, 16, and 17 (McGowan et al., 2002; Smith et al., 2001). These genes are responsible for the process by which keratin is formed and deposited in the outer most layer of the skin. In the dermatologic literature, PC is better known as Jadassohn-Lewandowsky syndrome (Karen & Schaffer, 2007; Strober, 2003).
PC may be hereditary (inherited from a parent who has PC; autosomal dominant) or may be spontaneous or sporadic (a mutation occurs during conception when no parent or other family member has PC) (Dahl, Daoud, & Su, 1995; Mouaci-Midoun, Cambiaghi, & Abimelec, 1996; Stratigos & Baden, 2001; Vaccaro, Guarneri, Barbuzza, & Guarneri, 2008). Few cases of autosomal recessive pachyonychia congenita have been reported. Some cases might appear in adult life (pachyonychia congenital tarda). Pachyonychia means thick nails, from the Greek words, pachys, thick, and onyx, nail. There are two subtypes of PC (see Table 1), but marks of PC may include (see Table 2): thickened nails (hypertrophic nail dystrophy), painful blisters and calluses on hands and feet (focal palmoplantar hyperkeratosis), follicular hyperkeratosis, and oral leukokeratosis (white film on tongue, cheeks, and sometimes larynx). Multiple cysts of various types (including steatocystoma and pilosebaceous cysts) develop during puberty which are useful features distinguishing PC2 from PC1. Other features include sores at the corner of the mouth (angular chelitis), teeth at or before birth (natal or pre-natal teeth), and hoarse voice (laryngeal involvement) (Cardinali, Torchia, Caproni, Petrini, & Fabbri, 2004; El-Matary & Barnard, 2004; Feinstein, Friedman, & Schewach-Millet, 1988; Kansky, 2007; Karen & Schaffer, 2007; Liao et al., 2007; Mahajan, Pall, Garg, & Gupta, 2003; Stratigos & Baden, 2001; Strober, 2003; Terrinoni et al., 2001).
The first case was documented in 1904 by Muller (Bondeson, 1993), followed by Wilson, Jadassohn, and Lewandowsky consecutively 1905 and 1906. In 1951, Jackson and Lawler described another new case (Bondeson, 1993). PC has no sex or ethnic group predilection. On the other hand, a search of the older literature discloses a number of older cases of definite pachyonychia congenita, some of them from the 17th and 18th centuries. In 1716, Musaeus described a case of the pachyonychia congenita syndrome in some detail (Bondeson, 1993).
Dermatology Nursing. 2009;21(6):351-353. © 2009 Jannetti Publications, Inc.
Cite this: Hereditary Palmoplantar Keratoderma: A Rare Case Report—Pachyonychia Congenita - Medscape - Nov 01, 2009.