Update on Clinically Relevant Genetic Testing in Pediatric Dermatology

Although the utility of molecular genetic testing has rocketed forward, karyotyping remains a useful tool particularly in the diagnosis of suspected chromosomal disorders. In disorders severe enough to suspect multiple genes are altered, CMA testing is the best first step. For suspected single-gene disorders, targeted single and multi gene panels are an increasingly useful means of making a diagnosis. Panel type tests containing multiple specific genes are especially useful in patients with overlapping features of multiple disorders. The number of approved clinical, commercially available tests continues to increase as costs continue to decrease. Due to improved technology and efficient, automated laboratory machines, WES/WGS has become attainable as a send-out test in many clinics. Although not suitable as first-line testing in most circumstances, they may be of particular benefit when other methods do not reveal a diagnosis. Human skin fibroblast culture has special utility for genetic testing in dermatology. Skin fibroblasts are an easily accessible cell source for genetic material that can be indefinitely stored and used for all forms of genetic testing. Skin fibroblasts are superior for the diagnosis of mosaic disorders. Finally, the ability to evaluate patients using clinical diagnostic criteria is essential to guide correct genetic testing. Recent major updates in the diagnostic criteria for Ehlers-Danlos syndrome, for example, aim to make phenotype-based genetic testing more efficient and accurate.