autosomal dominant dyskeratosis congenita (Scoggins type)
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Pathology
- also see dyskeratosis congenita
- defective telomere maintenance
- progressive bone marrow failure is the main cause of early mortality
- predisposition to malignancy
- pulmonary fibrosis
- hepatic fibrosis (cirrhosis)
- melanin is released by melanocytes & engulfed by dermal phagocytes
- defect of the immune system (probably in the afferent limb)
Genetics
- associated with defects in TERT
- associated with mutations in the TINF2 gene (type 3)
- Gene locus: 14q12, 5p15.33, 3q21-q28
Clinical manifestations
- reticular hyperpigmentation of the skin
- dystrophic nails
- osteoporosis
- premalignant leukokeratosis of the mouth mucosa
- absent fingerprints
- scant hair
- poor dentition
- absent lacrimal puncta
- palmar hyperkeratosis
- anemia
Laboratory
- complete blood count: anemia, thrombocytopenia
- cytogenetics
- endoreduplication on chromosome studies
- defect of the immune mechanism (probably in the afferent limb)