Question 282

Question:

A 24 year old 6’9” patient who is new to your city comes for a first checkup. He has a medical history significant for two idiopathic deep vein thromboses; he tells you that his brother also had a cerebral sinus thrombosis as a child and his mother had three spontaneous abortions. He has had eye problems in the past but doesn’t recall what they were. On physical exam, the patient appears to be very tall and lanky. He does not have hyperextensible joints, a notable chest wall deformity, or small genitalia. You order some lab tests. What genetic syndrome is this patient most likely to have?

Correct Answer: D.  Homocystinuria

This patient is most likely to have homocystinuria. It is an autosomal recessive disease caused by a deficiency of cystathionine beta synthase. Clinical manifestations include a tendency for idiopathic arterial or venous thrombosis, which is the most common cause of death. Other manifestations include ectopia lentis, Marfinoid habitus, and cognitive impairment.

Marfan syndrome is not associated with a tendency towards idiopathic thrombosis. Both Marfan and Ehlers-Danlos are likely to present with hyperextensible joints. Small genitalia are common in Kleinfelter syndrome. Antiphospholipid syndrome is associated with idiopathic thrombosis, but not with Marfanoid habitus or eye abnormalities.