What condition might be expected in a young man with a light skin tone, sparse hair, and lack of teeth?

The condition that can be expected in a young man with a light skin tone, sparse hair, and lack of teeth is ectodermal dysplasia. This genetic disorder affects the development of the ectoderm, one of the three primary layers of cells in the embryo, which gives rise to structures such as skin, hair, nails, and teeth. Individuals with ectodermal dysplasia often experience sparse hair or the complete absence of hair, along with missing teeth or abnormalities in tooth structure. The skin tone may be lighter due to a reduced amount of sweat glands and hair follicles, which is common in certain forms of this condition.

Other conditions listed, such as cleidocranial dysostosis, typically involve skeletal anomalies and may present with dental issues but do not primarily feature the combination of sparse hair and specific tooth absence associated with ectodermal dysplasia. Oligodontia refers specifically to the congenital absence of six or more teeth, which could be a symptom of ectodermal dysplasia but does not encompass the additional features like hair and skin changes. Down syndrome includes a range of physical and intellectual disabilities and does not specifically correlate with the distinct features described in the question.