Background: Pure hair–nail ectodermal dysplasia (PHNED) is a rare subtype of ectodermal dysplasia characterized by congenital hair and nail involvement, with teeth, sweating, and other ectodermal structures remaining unaffected when the disorder is fully phenotypically assessed. Only a limited number of PHNED cases have been reported, and the present father–son presentation adds to this rare clinical literature. PHNED has been associated with pathogenic variants in KRT74, KRT85, and HOXC13. Reported patients with HOXC13- associated PHNED often show severe hypotrichosis or complete alopecia with nail dystrophy; in the present family, the phenotype included congenital alopecia of the scalp, eyebrows, and eyelashes and dystrophy of all 20 nails.
Case presentation: A 27-year-old Yemeni man and his 7-monthold son presented with congenital total alopecia involving the scalp, eyebrows, and eyelashes, along with dystrophy of all 20 nails. Genetic testing identified an HOXC13 variant in the father; the son was clinically affected but was not genetically tested.
Conclusion: This father–son presentation is clinically consistent with PHNED and, in the genetically tested father, supports the association between HOXC13 variants and PHNED; it adds to the limited literature on HOXC13-associated hair–nail ectodermal dysplasia.