Molecular Diagnostics in Genodermatoses

Investigating the Prevalence, Gender Predilection, and Inheritance Patterns of Genodermatoses: A Tertiary Hospital Study

Genodermatoses encompass a spectrum of hereditary skin disorders stemming from mutations in genes pivotal for skin development, structure, and function. This study investigated the prevalence, gender predilection, and inheritance patterns of genodermatoses in a tertiary-level hospital through a one-year observational study. Among 157,051 dermatology outpatient department patients, 105 cases of genodermatoses were diagnosed, yielding a prevalence rate of 0.067%. Hamartoneoplastic syndromes and inherited disorders of cornification were the most prevalent subgroups, with neurofibromatosis type 1 and tuberous sclerosis complex 1 leading within these categories. The average age at presentation varied among different subgroups. A 2:1 male-to-female ratio was observed across all subgroups. Autosomal dominant inheritance was predominant. A positive family history in 46 cases and consanguinity among parents in 28 instances was reported. Genodermatoses pose diagnostic challenges due to their clinical complexity and rarity, which is compounded by limited epidemiological data. Molecular diagnosis advancements offer insights into genotype-phenotype correlations and facilitate genetic counseling and prenatal diagnosis (PND). Raising awareness among healthcare professionals and the public is critical for improving the quality of life for affected individuals.

What's New in Genetic Skin Diseases

The discoveries of new genes underlying genetic skin diseases have occurred at a rapid pace, supported by advances in DNA sequencing technologies. These discoveries have translated to an improved understanding of disease mechanisms at a molecular level and identified new therapeutic options based on molecular targets. This article highlights just a few of these recent discoveries for a diverse group of skin diseases, including tuberous sclerosis complex, ichthyoses, overgrowth syndromes, interferonopathies, and basal cell nevus syndrome, and how this has translated into novel targeted therapies and improved patient care.

[Genetics and dermatology]

Many types of genodermatosis exist, with numerous modes of transmission. The development of molecular genetic methods, in particular the most recent sequencing techniques, can be used to identify an increasing number of genes involved in these forms of genodermatosis while providing confirmation or more details regarding clinical diagnosis. Thanks to this approach, it is possible to determine risk of recurrence and to formulate an antenatal strategy. These technologies have led to improved molecular definition and to a better understanding of the physiopathological mechanisms involved in different genodermatoses such as bullous epidermolysis, keratinisation disorders, pigmentation disorders, potentially tumoral conditions, and epidermal and pilar dysplasia. The large amount of information provided by high-throughput sequencing makes it possible to study modifying genes as well as genotype-phenotype correlations. However, this genetic information in its turn poses problems of interpretation and of control of the resulting data. The use of genetics in dermatology for the purposes of diagnosis or research requires a consultation to provide patients with information regarding the genetic tests involved and the potential consequences thereof for them and their families. Furthermore, with pangenomic approaches there is a higher probability of fortuitous discovery of abnormalities such as variants associated with risks predisposing to cancer or neurodegenerative disease. Collaboration between dermatologists and geneticists enables optimisation of patient management in terms of diagnosis and genetic counselling in the event of such rare diseases. Therapeutic applications are beginning to be developed. The scope of therapeutic application includes gene therapy, replacement therapy (enzyme therapy) and targeted therapy.

Genetic Testing in Dermatology: A Survey Analyzing Obstacles to Appropriate Care

BACKGROUND/OBJECTIVES

The past several decades have witnessed unprecedented advances in genomic technology, bringing genetic testing to the forefront of medical practice and moving us towards the practice of personalized medicine. Genetic testing has become an important aspect in preempting and successfully treating diseases in dermatology, yet difficulty remains in regards to obtaining genetic testing for patients. We conducted a survey for pediatric dermatologists in order to try to gauge and understand where difficulties lie in obtaining genetic testing and to analyze how best these issues can be resolved.

METHODS

An 18-question survey was emailed to 480 dermatologists who have attended at least one of the last three annual Society for Pediatric Dermatology (SPD) meetings.

RESULTS

Virtually all providers encountered at least one situation in which they required genetic testing for a patient (97.3% [n = 108]) and 37.4% indicated needing genetic testing more than six times per year. Of the respondents who had attempted to obtain genetic testing, half were unsuccessful in obtaining coverage more than 75% of the time (45% [n = 32]) and only 7.0% (n = 5) achieved success 75% to 100% of the time. The most common reasons for obtaining genetic testing included the need to provide an accurate diagnosis, followed by the need to provide prognostic information and appropriate medical management.

CONCLUSION

The role of genetic testing in the practice of dermatology is expanding, yet obtaining coverage for genetic testing remains a challenge. We propose several solutions as to how this can be remedied.

Next generation diagnostics of heritable connective tissue disorders

Finding pathogenic mutations in monogenic diseases represents one of the significant milestones of late 20th century molecular genetics. Mutation data can improve genetic counseling, assist disease modeling and provide a basis for translational research and therapeutics. The logistics of detecting disease mutations, however, has not always been easy or straightforward. Traditional approaches using genetic linkage or candidate gene analysis have often been laborious and expensive, but the advent of next generation sequencing technologies is changing the very nature of modern-day gene discovery and mutation detection. The application of whole-exome and whole-genome sequencing has demonstrated how these new approaches can improve diagnostic sensitivity as well as disclose completely novel and unsuspected disease-gene associations. Use of next generation sequencing in inherited diseases that display genetic heterogeneity is already a cost-effective methodology for mutation detection. Further reductions in sequencing costs and machine run time, as well as improved bioinformatics, are likely to lead to the incorporation of next generation sequencing into routine diagnostics within clinical genetics. In the short term, the impact of next generation sequencing on the genetically diverse and clinically protean heritable connective tissue disorders is likely to mean more comprehensive documentation of individual mutations. Longer term, dissection of bioinformatics data may lead to further insight into individual prognosis and an era of new personal therapeutics.