A 19-year-old male presents with a high arch palate and ches

A 19-year-old male presents with a high arch palate and chest wall deformities. He is tall and thin, and is also noted to have livedo reticularis. Which of the following is not associated with this syndrome?

Intellectual impairment

Upward dislocation of the lens

Venous and arterial thrombosis

Osteoporosis

Autosomal recessive inheritance

Answer: Upward dislocation of the lens

The description is of homocystinuria. Homocystinuria is an autosomal recessive disorder of methionine metabolism that is caused by a deficiency in cystathionine synthase or by one of several defects in the methionine recycling pathway. There is abnormal accumulation of homocysteine in the plasma and urine with pathological effects in the connective tissue, muscles, CNS, and cardiovascular system. Patients have a Marfinoid habitus with arachnodatyly and long limbs. Downward dislocation of the lens is a feature. Other opthalmic pathology include optic atrophy, glaucoma, cataracts and retinal detachment. Approximately 50% of patients are developmentally delayed, and psychiatric problems are common. There is an increased predisposition to intravascular thrombosis which can result in renal artery stenosis, portal vein thrombosis, intermittent claudication, coronary artery and carotid artery occlusion. Cerebral thrombosis, pulmonary embolism, myocardial infarction and other thromboembolic complications are an important cause of death. Dissecting aneurysms of the aorta or pulmonary artery can occur. Homocystinuria results in high concentrations of amino acids that inhibit tyrosinase. This results in hypopigmentation and fine easily breakable hair. Occasionally, patients have malar rashes, telangiectasia and livedo reticularis. Osteoporosis especially of the spine is a troublesome complication. Subjects with Marfan's syndrome, although similar in body habitus, do not present with osteoporosis, arterial and venous thrombosis, or the cognitive impairment seen in homocystinuria. In Marfan's syndrome there is usually upward dislocation of the lens.