Type IV Ehlers Danlos syndrome and factor IX deficiency: A case report

The patient, S.D., a 28-year-old female, came to our attention for mild haemorrhagic diathesis and signs suggestive of a collagen disorder, such as joint and skin hyperextensibility, bronchiectasis, mitral valve prolapse and visceral ptosis. The levels of hydroxylysine (Hyl) glycosides in skin insoluble collagen and in 24 hr urine samples were in the normal range as were urinary free Hyl levels. The amino acid analysis of skin collagen showed a normal ratio of Hyl to Lysine, whereas interrupted SDS-PAG electrophoresis of skin insoluble collagen showed a sharp reduction of the α₁ (III) monomer band. The haemostatic tests demonstrated only mild defects of both F IX:C and F IXR:Ag, and a slightly prolonged thrombotest. This behaviour is compatible with that of a haemophilia B carrier with an accompanying B^m defect. On the basis of the biochemical collagen characterization and the mild F IX deficiency, the diagnosis of a possible form of type IV EDS associated with subhaemophilia B was made.