USMLE forum
Step 1
Step 2 CK
Step 2 CS
Matching & Residency
Step 3
  <<   < *  Step 1   *  >   >>  

* ques...1
  drjk - 02/24/10 21:29
  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?

A. Marfan syndrome
B. Ehlers-Danlos syndrome
C. Kleinfelter syndrome
D. Homocystinuria
E. Antiphospholipid syndrome
Report Abuse


* Re:ques...1
  drjd2010 - 02/24/10 21:43
Report Abuse

* Re:ques...1
  phaidau - 02/24/10 22:22
  so, u mean SLE??  
Report Abuse

* Re:ques...1
  drjd2010 - 02/24/10 22:42
  No. (google it)  
Report Abuse

* Re:ques...1
  phaidau - 02/24/10 22:47
  thanks... here the link..
Report Abuse

* Re:ques...1
  drjk - 02/24/10 23:01
  no guys .....the ans is d.....
and the expl is....

D is the correct answer

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.
Report Abuse

* Re:ques...1
  drjd2010 - 02/24/10 23:09
  wow i totally read that wrong. my mistake.  
Report Abuse

* Re:ques...1
  sammy10 - 02/24/10 23:33
  Can anyone tell me what is the difference between ectopia lentis of homocystenuria and Marfan syndrome?  
Report Abuse

* Re:ques...1
  drjk - 02/24/10 23:44
  from e medicine

# Marfan syndrome is the most frequent cause of heritable ectopia lentis. The syndrome is transmitted as an autosomal dominant trait with variable expressivity and has a prevalence of approximately 5 per 100,000. Several point mutations involving the fibrillin gene on chromosomes 15 and 21 have been described and may relate to incompetent zonular fibers. Salient features of Marfan syndrome include tall stature, arachnodactyly, joint laxity, mitral valve prolapse, aortic dilatation, axial myopia, and increased incidence of retinal detachment. Lens dislocation occurs in about 75% of patients with Marfan syndrome and usually is bilateral, symmetrical, and supertemporal.
# Homocystinuria is the second most common cause of hereditary ectopia lentis. It is an inborn error of metabolism most often caused by a near absence of cystathionine b-synthetase (the enzyme that converts homocysteine to cystathionine). Patients typically have fair skin with coarse hair, osteoporosis, mental retardation (nearly 50%), seizure disorder, marfanoid habitus, and poor circulation. Thromboembolic events constitute the major threat to survival, especially following general anesthesia. Lens luxation usually is bilateral, symmetrical, and inferonasal, and presents in nearly 90% of patients. Deficient zonular integrity secondary to the enzymatic defect has been implicated as the primary cause of lens displacement.
Report Abuse

* Re:ques...1
  sammy10 - 02/24/10 23:49
  In Marfan the lens is displaced SUPERIORLY and in Homocystenuria it is displaced INFERIORLY  
Report Abuse

* Re:ques...1
  shrea80 - 02/25/10 00:08
  what is the cause of being very tall(here 6'9'') and lanky in homocysteinuria?does anybody know this mechanism?  
Report Abuse

          Page 1 of 2     [Next >]     [Last >>]

[<<First]   [<Prev]  ... Message ...  [Next >]   [Last >>]

Logon to post a new Message/Reply




Step 1 Step 2 CK Step 2 CS Matching & Residency Step 3 Classifieds
LoginUSMLE LinksHome