IQoL-32: a new ichthyosis-specific measure of quality of life.

BACKGROUND: Inherited ichthyoses are associated with impaired quality of life (QoL). OBJECTIVES: The aim of this study was to create and validate a QoL questionnaire specifically dedicated to patients with ichthyosis. METHODS: A prequestionnaire was drawn after selecting items from a verbatim transcript. It was then subjected to a cognitive debriefing. During the validation step, this questionnaire was sent to patients with the Dermatology Life Quality Index, Short Form-12 health-related questionnaire, and severity scores (global severity: mild/moderate/severe/very severe; clinical severity evaluated by 6 visual analog scales). A shortened version of the questionnaire was designed. The validity of the tool was confirmed: for its structure and 1-dimensional nature (Cronbach α), convergent (Spearman correlation) and discriminating (Tukey test) validity; α risk was fixed at 5%. RESULTS: The initial questionnaire included 60 items. During the validation phase, 59 subjects were tested. The shortened version included 32 items (IQoL-32) and 7 dimensions (Cronbach α: 0.94). The higher the score, the more impacted the QoL. IQoL-32 was positively correlated to Dermatology Life Quality Index (P < .0001) and negatively to Short Form-12 health-related questionnaire (P < .0001). IQoL-32 was highly correlated to clinical severity: overall analysis (Spearman ranking: 0.72; P < .0001) or analysis per dimension (highest correlations: discomfort, pain, interpersonal relations). IQoL-32 demonstrated a higher correlation with visual analog scale compared with Dermatology Life Quality Index and Short Form-12 health-related questionnaire. It also showed a good discriminating power (P < .0001) according to overall severity levels. LIMITATIONS: Only patients residing in France were included. CONCLUSION: IQoL-32 is a specific and validated questionnaire for inherited ichthyosis. It will be very useful for patient care and research.

Hornerin is a component of the epidermal cornified cell envelopes.

A single-nucleotide polymorphism within the gene encoding hornerin (HRNR) has recently been linked with atopic dermatitis (AD) susceptibility. HRNR shares features with filaggrin, a key protein for keratinocyte differentiation, but conflicting reports have been published concerning its expression in the epidermis, and its role is still unknown. To analyze HRNR expression and function in the epidermis, anti-HRNR antibodies were produced and used in Western blot analysis and immunohistochemical, confocal, and immunoelectron microscopy analyses of human skin and of cornified cell envelopes purified from plantar stratum corneum. We also tested whether HRNR was a substrate of transglutaminases. In the epidermis, HRNR was detected at the periphery of keratohyalin granules in the upper granular layer and at the corneocyte periphery in the whole cornified layer. Detected in Western blot analysis as numerous bands, HRNR was relatively insoluble and only extracted from epidermis with urea and/or reducing agents. The presence of HRNR in the purified envelopes was confirmed by immunoelectron microscopy and by Western blot analysis after V8-protease digestion. HRNR was shown to be a substrate of transglutaminase 3. These data demonstrate that HRNR is a component of cornified cell envelopes of human epidermis. Its reduced expression in AD may contribute to the epidermal barrier defect observed in the disease.