Hereditary benign intraepithelial dyskeratosis

Hereditary Benign Intraepithelial Dyskeratosis (HBID) is a rare genetic disorder characterized by the presence of thick, gelatinous dyskeratotic lesions on the conjunctiva of the eyes and the oral mucosa. First identified in the Haliwa-Saponi Native American tribe in North Carolina, HBID has since been observed in other populations, though it remains relatively uncommon. The condition is benign and primarily affects the mucous membranes, leading to distinctive clinical features.

Etiology and Genetics

HBID is inherited in an autosomal dominant manner, meaning a single copy of the altered gene in each cell is sufficient to cause the disorder. The gene associated with HBID has been localized to chromosome 4q35, but the specific gene and the nature of the genetic mutation have not been fully elucidated. The genetic basis of HBID suggests a high degree of penetrance, with most individuals carrying the gene exhibiting some form of the disease symptoms.

Clinical Features

The hallmark of HBID is the development of thick, white plaques on the mucous membranes, particularly the conjunctiva and the oral mucosa. These lesions are typically bilateral and symmetrical. In the eye, this can lead to conjunctivitis, irritation, and a sensation of a foreign body in the eye. In the mouth, the lesions can cause discomfort, but they are generally not associated with significant morbidity.

Diagnosis

Diagnosis of HBID is primarily clinical, based on the characteristic appearance of the lesions and a family history consistent with autosomal dominant inheritance. Biopsy of the lesions can confirm the diagnosis, showing typical dyskeratotic cells within the epithelium. Genetic testing may be helpful in uncertain cases but is not routinely performed due to the rarity of the condition and the lack of specific genetic markers.

Management and Treatment

There is no cure for HBID, and treatment is symptomatic. For ocular lesions, lubricating eye drops and ointments can help alleviate discomfort. In severe cases, surgical removal of the lesions may be necessary, although they can recur. Oral lesions generally require no treatment unless they result in significant discomfort or interfere with eating, in which case topical anesthetics or corticosteroids may be used.

Prognosis

The prognosis for individuals with HBID is generally good, as the condition is benign and does not affect life expectancy. However, the recurrent nature of the lesions can lead to ongoing discomfort and may require multiple treatments.

Epidemiology

HBID is most commonly reported in the Haliwa-Saponi Native American tribe in North Carolina, but it has been identified in other populations as well. The exact prevalence of the disorder is unknown due to its rarity and the potential for underdiagnosis.