RGD uses the Human Disease Ontology (DO, https://disease-ontology.org/) for disease curation across species. RGD automatically downloads each new release of the ontology on a monthly basis. Some additional terms which are required for RGD's curation purposes but are not currently covered in the official version of DO have been added. As corresponding terms are added to DO, these custom terms are retired and the DO terms substituted in existing annotations and subsequently used for curation.
Central centrifugal cicatricial alopecia (CCCA) is the most common type of primary scarring alopecia affecting women of African ancestry, with an estimated prevalence of 2.7 to 5.6%. It may be triggered by hair-grooming habits; however, familial occurrence has been reported. Mean age at presentation is 36 years. The first sign is often unexplained hair breakage, followed by hair thinning, primarily involving the vertex scalp and progressing centrifugally. Histopathologic examination shows varying degrees of lymphocytic inflammation, follicular degeneration, and fibrosis. (OMIM)