A 5-year-old boy had two X-linked recessive disorders, hypohidrotic ectodermal dysplasia and X-linked ichthyosis. His mother and two older sisters were identified as heterozygotes although they appeared normal on physical examination. A decreased sweat pore count, frequently found in carriers of hypohidrotic ectodermal dysplasia, was demonstrated in all three individuals. Additionally, they had the deep corneal dystrophy of X-linked ichthyosis that has been observed not only in affected males but also in a high percentage of heterozygous females. Identification of the mother and sisters of the proband as heterozygotes enabled us to provide more effective genetic counseling for this family.
Esterly NB, Pashayan HM, West CE. Concurrent Hypohidrotic Ectodermal Dysplasia and X-Linked Ichthyosis. Am J Dis Child. 1973;126(4):539–543. doi:10.1001/archpedi.1973.02110190435017