Novel and recurrent mutations in keratin 1 cause epidermolytic ichthyosis and palmoplantar keratoderma

Mutations in keratin genes underlie a variety of epidermal and nonepidermal cell-fragility disorders, and are the genetic basis of many inherited palmoplantar keratodermas (PPKs). Epidermolytic PPK (EPPK) is an autosomal dominant disorder that can be due to mutations in the keratin 1 gene, KRT1. Epidermolytic ichthyosis (EI), the major keratinopathic ichthyosis, is characterized by congenital erythroderma, blistering and erosions of the skin. Causative mutations in KRT1 and KRT10 have been described, with PPK being present primarily in association with the former. We report four unrelated cases (one with sporadic EI and three with autosomal dominant PPK), due to two novel and two recurrent KRT1 mutations. Mutations in KRT1 are not only scattered throughout the keratin 1 protein, as opposed to being clustered, but can result in a range of phenotypes as further confirmed by these mutations, giving a complex genotype/phenotype pattern.

Mutations in desmoglein 1 cause diverse inherited palmoplantar keratoderma phenotypes: implications for genetic screening

The inherited palmoplantar keratodermas (PPKs) are a heterogeneous group of genodermatoses, characterized by thickening of the epidermis of the palms and soles. No classification system satisfactorily unites clinical presentation, pathology and molecular pathogenesis. There are four patterns of hyperkeratosis - striate, focal, diffuse and punctate. Mutations in the desmoglein 1 gene (DSG1), a transmembrane glycoprotein, have been reported primarily in striate, but also in focal and diffuse PPKs. We report seven unrelated pedigrees with dominantly inherited PPK owing to mutations in the DSG1 gene, with marked phenotypic variation. Genomic DNA from each family was isolated, and individual exons amplified by polymerase chain reaction. Sanger sequencing was employed to identify mutations. Mutation analysis identified novel mutations in five families (p.Tyr126Hisfs*2, p.Ser521Tyrfs*2, p.Trp3*, p.Asp591Phefs*9 and p.Met249Ilefs*6) with striate palmar involvement and varying focal or diffuse plantar disease, and the recurrent mutation c.76C>T, p.Arg26*, in two families with variable PPK patterns. We report one recurrent and five novel DSG1 mutations, causing varying patterns of PPK, highlighting the clinical heterogeneity arising from mutations in this gene.

Reactivity to autologous serum skin test and relationship with complement levels in chronic idiopathic urticaria and angio-oedema

BACKGROUND

A role for complement in autoantibody-mediated histamine release in urticaria has been suggested but not proven in vivo. Aim. To study serum complement levels in patients with chronic idiopathic urticaria (CIU) and to determine whether there was a relationship with autologous serum skin test (ASST) reactivity.

METHODS

We recruited 35 patients with CIU. Complement (C3, C4) levels and ASST were measured in all patients; additional investigations were undertaken dependent on history and examination.

RESULTS

Complement concentrations were outside the population reference intervals in 19/35 patients, with low C3 noted in 3/35 and low C4 in 18/35. Of 12 patients with a positive ASST, 7 had low complement levels, and 12/23 with a negative ASST had low complement levels. Patients with a positive ASST had a median C3 of 1.24 g/L (range 0.35-1.51) compared with a median of 1.25 g/L in those with a negative ASST (P = 0.36), and a median C4 of 0.20 g/L (range 0.185-0.452) in those with a positive ASST compared with 0.18 g/L in those with a negative ASST (P = 0.88).

CONCLUSIONS

We conclude that both a reduction in C4 and positive ASST are common in CIU and although these immunological abnormalities often coexist, there is no clear relationship between them. Other components of the complement system may be worth exploring.

Plantar warts treated with an immune response modifier: a report of two cases

Viral warts are the most common disease of the skin and are caused by human papillomavirus (HPV). Plantar warts, a manifestation of infection by HPV-1, -2 and -4, tend to be smoother and flatter than common warts and can also be painful when pressure is applied. A variety of local treatments, including topical salicyclic acid, cryotherapy, topical 5-fluorouracil, intralesional interferons and photodynamic therapy, are available to treat plantar warts. Here we report two cases of plantar warts, which had been previously treated without success. Total clearance of the warts was observed in both cases after treatment with imiquimod 5% cream over a period of 12 weeks. No evidence of local skin reactions was observed in either case during the treatment period. Recurrent lesions were not evident in the follow-up period for each patient.

Erosive pustular dermatosis of the leg associated with compression bandaging and fungal infection

BACKGROUND

Erosive pustular dermatosis of the leg (EPDL) has been described in association with venous insufficiency and atrophy of the skin of the lower leg. Like erosive pustular dermatosis of the scalp, this disease has also been reported to be a non-infective condition.

OBJECTIVES

To investigate the clinicopathological features and, where possible, the aetiology of clinical EPDL.

METHODS

We identified a group of patients undergoing continuous compression bandaging for venous dermatitis of the legs and/or predominantly venous leg ulceration with clinical features described in patients with EPDL. They were investigated by skin biopsy, patch testing and microbiological tests for the presence of bacteria and fungi.

RESULTS

Twenty-four of 400 (6%) patients were noted to have pustules on the leg(s). There was laboratory evidence of fungal infection in 13 of 24 patients (54%), with complete and sustained resolution of pustules after antifungal treatment. Pustulation in the other 11 patients (46%) was unresponsive to antibiotics for confirmed bacterial infection; some improvement was seen with potent topical corticosteroids but full clearance was achieved only after a switch from continuous four-layer compression bandaging to the use of intermittent long stretch compression.

CONCLUSIONS

EPDL is a fairly common clinical picture seen in patients undergoing continuous compression bandaging. It may be produced by opportunistic, particularly fungal, infection. In almost half an infective aetiology cannot be demonstrated and a pyoderma gangrenosum-like process may be implicated.