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.

Skin-cancer awareness in Scottish cardiac transplant recipients

BACKGROUND

Cardiac transplant recipients have a greatly increased risk of nonmelanoma skin cancer, with a relative risk of up to 108. Skin cancer is more aggressive in transplant patients and results in substantial morbidity and mortality. It is therefore important that these patients understand this risk and take adequate sun-protection measures.

AIM

To assess awareness of skin cancer risk and sun protection measures used by cardiac transplant recipients and determine the impact of patient education.

METHODS

Using a detailed questionnaire, we surveyed 118 patients attending the cardiac transplant clinic at our centre to quantify knowledge of skin cancer risk (maximum total score 10) and behaviour in the sun (maximum total score 15). Of these patients, 50 were then seen by a dermatologist for education about skin cancer risk, sun protection measures and skin cancer screening. Six months later, we asked them to complete the same questionnaire again.

RESULTS

The mean knowledge score was 7.3/10 and the mean behaviour score was 11.2/15. In the group that received education, the mean knowledge score improved from 7.2/10 before the dermatology consultation to 7.8/10 after the consultation (P < 0.03). The mean score for the behaviour questions improved even more, from 11.2/15 before to 13.5/15 after the consultation (P < 0.0001). CONCLUSIONS. This study demonstrates that specialist advice can improve self-reported knowledge of skin cancer risk and sun protective behaviour in cardiac transplant recipients. It is hoped that this may reduce the risk of nonmelanoma skin cancer in these patients.

Expression of the sarco/endoplasmic reticulum calcium ATPase type 2 and 3 isoforms in normal skin and Darier's disease

BACKGROUND

Darier's disease (DD) is caused by mutations in ATP2A2, which encodes the sarco/endoplasmic reticulum calcium ATPase type 2 (SERCA2), a member of a family of calcium pumps important in intracellular calcium signalling. SERCA2 has two isoforms. SERCA2a occurs mainly in cardiac and skeletal muscle, whereas SERCA2b occurs ubiquitously and is coexpressed with the related SERCA type 3 (SERCA3) in many tissues. It is not known why mutations in the widely expressed SERCA2 manifest as a focal skin disease.

OBJECTIVES

To provide insight into the pathogenesis of DD by examining SERCA isoform expression in normal skin and DD skin.

METHODS

Using immunohistochemistry we studied SERCA2a, SERCA2b and SERCA3 expression in nonlesional and lesional skin from seven patients with DD and normal skin from seven control subjects. We quantified SERCA2a and SERCA2b staining intensity by grey scale analysis of fluorescence intensity.

RESULTS

In normal and DD epidermis both SERCA2a and SERCA2b staining was seen. SERCA2a staining in epidermis was less intense relative to pilar muscle whereas SERCA2b staining in epidermis was of marginally greater intensity than in pilar muscle. SERCA3 was not expressed in normal or DD epidermis, but was found in eccrine glands and blood vessels. No reduction was detected in SERCA2a or SERCA2b staining intensity in DD nonlesional epidermis compared with control epidermis. In within-patient comparisons, SERCA2a and SERCA2b staining in lesional epidermis was less intense than in nonlesional epidermis.

CONCLUSIONS

Both SERCA2a and SERCA2b are present in epidermis, although the latter may predominate. The absence of coexpressed SERCA3 in epidermis may explain the localization of DD. Comparable SERCA2 staining intensity in nonlesional DD and control epidermis, even in patients predicted to be haploinsufficient, suggests partial compensation by upregulation of the normal allele. Unknown additional factors may trigger focal lesions by overcoming this compensation. Reduced staining intensity in lesional tissue may be secondary, or may reflect local downregulation of SERCA2 expression predisposing to development of focal lesions.

Allergic contact dermatitis in venous leg ulcer patients

Our aim was to determine the frequency and nature of contact sensitivity in venous leg ulcer patients in Lanarkshire. We performed patch testing with the European standard series, antimicrobials and medicaments on 200 patients referred to our leg ulcer clinics. Positive patch tests were found in 136 (68%) patients. Multiple allergies occurred in 102 (51%). The most frequent allergen groups were fragrances (30.5%), antimicrobials (19.5%), topical excipients (19.5%), rubber accelerators (13.5%) and topical corticosteroids (8%). We also found a high prevalence of positive patch tests to Intrasite gel (9.5%) and Hioxyl cream (8.5%), medicaments which are commonly used to treat leg ulcers in our area. Contact sensitivity is common in venous leg ulcer patients and has important implications for patient management. The allergens involved vary depending on local nursing practice. We suggest that all venous leg ulcer patients be patch tested with a locally relevant patch test series.

Leucocytoclastic vasculitis and influenza vaccination

Influenza vaccination is recommended for all people over 75 years of age and for an expanding range of other indications. Side-effects of influenza vaccination are usually mild but we describe four cases of leucocytoclastic vasculitis following influenza vaccination. The four patients, who were all elderly, presented with cutaneous vasculitis but all had abnormal urinalysis suggestive of associated renal involvement. Since 1974 only 10 cases of vasculitis following influenza vaccination have been reported in the literature. The clinical features of these cases are reviewed. As the use of influenza vaccination is likely to increase, dermatologists should be aware of the possible association with vasculitis.

Genetic epidemiology of Darier's disease: a population study in the west of Scotland

BACKGROUND

Darier's disease has a world-wide distribution, but estimates of prevalence have varied. The discovery that the disease is due to mutations in ATP2A2 provides the opportunity to study the genetic epidemiology of the disease in localized populations.

OBJECTIVES

To survey the prevalence of Darier's disease in the west of Scotland and look for founder effects in this population.

METHODS

We ascertained cases of Darier's disease in the west of Scotland and used genealogy and mutational analysis to seek common ancestry.

RESULTS

Seventy-eight current cases were identified, giving a prevalence of approximately 1 : 30 000. While 63 cases gave a history of Darier's disease in previous generations, conventional genealogy identified only two pairs of two family groups with common ancestry within the last 180 years. Eleven patients (14%; three of whom had in total four affected children) had probable de novo mutations. Causative mutations in ATP2A2 have been identified in 11 of 15 pedigrees screened for mutation, but no two share the same mutation.

CONCLUSIONS

High estimates of prevalence are likely to be due to intensive ascertainment, rather than founder effects. Darier's disease is likely to be more common than has been recognized in other populations.

Platelet and cardiac function in Darier's disease

ATP2A2, the gene that is abnormal in Darier's disease, encodes SERCA2, a calcium pump that is expressed in many tissues. The wide expression of SERCA2 might suggest that ATP2A2 mutations would cause a multisystem disease. There is however, no evidence of consistent extracutaneous manifestations of Darier's disease. We have conducted preliminary studies in patients with Darier's disease, in two extracutaneous systems in which SERCA2 is known to be important, in order to investigate whether subtle defects have been overlooked. We found no evidence for altered cardiac function in 10 patients using two-dimensional, colour and Doppler echocardiography. There were no consistent defects in platelet function in 12 patients, using bleeding time and aggregation studies. We conclude that the skin is sensitive to defects in SERCA2 function to which other systems appear robust.