Hereditary benign intraepithelial dyskeratosis (HBID) is a rare autosomal dominant disorder characterized by elevated epibulbar and oral plaques and hyperemic conjunctival blood vessels. The condition is predominantly seen in Native Americans belonging to the Haliwa-Saponi tribe located in northeastern North Carolina.
To determine whether HBID can be diagnosed using cytologic preparations of the conjunctiva, and whether the cytologic findings correlated with the genetic linkage involving a duplication in chromosome 4 (4q35).
Cytologic preparations from conjunctival brushings in patients afflicted with HBID and from unaffected blood relatives with normal conjunctivas were compared in a masked fashion. Cytologic observations were correlated with molecular genetic analyses.
Papanicolaou-stained preparations from the conjunctiva showed the typical cytologic features of HBID, including rounded squamous epithelial cells with dense homogenous orange cytoplasm and hyperchromatic, pyknotic, or crenated nuclei. All cases with the diagnostic cytologic findings of HBID had a duplication in chromosome 4 (4q35).
HBID is an entity with distinct clinical, histopathologic, and genetic features. The results of this study indicate the diagnosis can also be supported in an appropriate clinical setting when adequate epibulbar cytology preparations are obtained and the characteristic genetic attributes are present.