Challenges in Treating Genodermatoses: New Therapies at the Horizon

Abstract

Genodermatoses are rare inherited skin diseases that frequently affect other organs. They often have marked effects on wellbeing and may cause early death. Progress in molecular genetics and translational research has unravelled many underlying pathological mechanisms, and in several disorders with high unmet need, has opened the way for the introduction of innovative treatments. One approach is to intervene where cell-signaling pathways are dysregulated, in the case of overactive pathways by the use of selective inhibitors, or when the activity of an essential factor is decreased by augmenting a molecular component to correct disequilibrium in the pathway. Where inflammatory reactions have been induced by a genetically altered protein, another possible approach is to suppress the inflammation directly. Depending on the nature of the genodermatosis, the implicated protein or even on the particular mutation, to correct the consequences or the genetic defect, may require a highly personalised stratagem. Repurposed drugs, can be used to bring about a “read through” strategy especially where the genetic defect induces premature termination codons. Sometimes the defective protein can be replaced by a normal functioning one. Cell therapies with allogeneic normal keratinocytes or fibroblasts may restore the integrity of diseased skin and allogeneic bone marrow or mesenchymal cells may additionally rescue other affected organs. Genetic engineering is expanding rapidly. The insertion of a normal functioning gene into cells of the recipient is since long explored. More recently, genome editing, allows reframing, insertion or deletion of exons or disruption of aberrantly functioning genes. There are now several examples where these stratagems are being explored in the (pre)clinical phase of therapeutic trial programmes. Another stratagem, designed to reduce the severity of a given disease involves the use of RNAi to attenuate expression of a harmful protein by decreasing abundance of the cognate transcript. Most of these strategies are short-lasting and will thus require intermittent life-long administration. In contrast, insertion of healthy copies of the relevant gene or editing the disease locus in the genome to correct harmful mutations in stem cells is more likely to induce a permanent cure. Here we discuss the potential advantages and drawbacks of applying these technologies in patients with these genetic conditions. Given the severity of many genodermatoses, prevention of transmission to future generations remains an important goal including offering reproductive choices, such as preimplantation genetic testing, which can allow selection of an unaffected embryo for transfer to the uterus.

Targeting of Th17-related cytokines in patients with Darier Disease

“…Treatment of genodermatoses in general is challenging. (Morren et al 2022) Because of the small patient population, it is almost impossible to conduct clinical trials and thus get drugs approved. There is a very limited number of effective treatments for DD, and there are no randomized, placebo-controlled trials.…”

Differentiation of pluripotent stem cells for modeling human skin development and potential applications

“…Inherited disorders of the skin are generally caused by mutations in the genes encoding for intermediate filaments and structural proteins such as keratins or collagens. They span a diverse group of blistering and disfiguring diseases and affect many individuals in every ethnic group ( Morren et al, 2022 ). The use of iPSCs for the development of personalized medicine therapies holds great promise in the treatment of diseases caused by genetic disorders ( Khurana et al, 2021 ), and a clear understanding of the pathways affected will help to develop therapeutic cures.…”

Antibody gene transfer treatment drastically improves epidermal pathology in a keratitis ichthyosis deafness syndrome model using male mice

“…Genodermatoses are inherited skin diseases that often present with multisystem involvement leading to increased morbidity and mortality. 1 Mutations in five Cx genes expressed in the epidermis ( GJA1, GJB2 , GJB3, GJB4 and GJB6 ) can cause a variety of rare genodermatoses for which there is no cure, ranging in severity from mild increases in skin thickness to life-threatening and fatal barrier break down. 2 For these, as well as all other numerous Cx-related diseases, there is a compelling need to develop specific therapeutics.…”