DSP - Related Ectodermal Dysplasia Sequencing Test Details
The DSP gene plays an important role in a part of the cell call the desmosomes. Desmosomes are important in intracellular junction in epithelia cells. Abnormalities in the DSP gene can result in clinical features in the parts of the body where these desmosomes are critical such as the skin, hair, nails, and the heart. Ectodermal dysplasia and skin fragility syndrome is characterized by skin that is fragile with blisters and peeling, dystrophic nails, and palmoplantar keratosis. DSP-related ectodermal can range in severity and include other features such as woolly hair, alopecia, hyperkeratotic plaques, failure to thrive, neonatal teeth, dilated cardiomyopathy, and arrhythmogenic right ventricular cardiomyopathy. The most severe presentation is lethal acantholytic epidermolysis bullosa where newborns will experience severe erosions at birth, ultimately resulting in neonatal death. Carvajal syndrome is characterized by cardiomyopathy and woolly hair. There have been several reports of DSP variants associated with this phenotype. The inheritance pattern of DSP-related syndromes varies, depending on the condition.
Sequencing for the DSP gene should be considered in individuals expressing features of DSP-related ectodermal dysplasias such as skin fragility or cardiomyopathy with wooly hair. There is overlap between several types of epidermolysis bullosa simplex, however those the lethal acantholytic epidermolysis bullosa caused by pathogenic DSP variants presents without blisters which differentiates it from other types of EB.
This test is performed by Sanger sequencing of the coding regions and splice sites of the DSP gene. This test does not detect large deletions or variants in non-coding regions that could affect gene expression.
Analytical and Clinical Sensitivity
This test is greater than 99.9% accurate in detecting variants in the sequence analyzed. While the clinical detection rate may vary depending on which type of DSP-related ectodermal dysplasia an individual has, these rates are not well understood.