Introduction: Hypohidrotic ectodermal dysplasia (HED) is an X-linked recessive disorder, characterised by abnormally developed ectodermal tissues (sweat glands, enamel, hair, nails). HED is caused by mutations of the EDA1 gene (Xq13.1) which codes for ectodysplasin A, a transmembrane signalling protein, which plays a significant role in ectodermal differentiation. Here we present a case of prenatal testing for HED.
Methods: An 11-month-old boy with no family history was clinically diagnosed with HED. Genomic DNA was isolated from the patient's white blood cells, and the possible existence of mutations suspected for HED development was investigated by an NGS gene panel. Total DNA was also isolated from blood samples of his parents. After mutation detection and genetic counselling, a prenatal HED test was performed during the 12th week of the mother's next pregnancy. Embryonic DNA was isolated from a sample of chorionic villi. Parts of the EDA1, AMELX (X chromosome), and SRY (Y chromosome) genes were amplified by PCR, using the corresponding primers.
Results: The boy with HED was found to be a hemizygote for the c.595_613del (p. Pro199PhefsTer75) deletion in the EDA1 gene. The fetus was male (XY) that did not carry the pathological mutation.
Conclusion: The initial diagnosis of a family member with HED in a case with no family history poses the question whether this type of ectodermal dysplasia is autosomal dominant (and the case is due to a de novo mutation), autosomal recessive, or X-linked recessive. Molecular detection of the responsible mutation allows proper genetic counselling, carrier testing, and prevention by prenatal testing.
Keywords: Ectodermal dysplasia; Mutation; Prenatal testing; X-linked recessive inheritance.
© 2021. The Author(s), under exclusive license to Springer Nature Switzerland AG.