Ischaemic heart disease - Hyperhomocysteinaemia Factor

Definition

The RMA defines hyperhomocysteinaemia to mean "a condition characterised by an excess of homocysteine in the blood".

General information

Homocysteine is an amino acid (one of the chemical compounds that forms proteins). Everyone produces it, mainly from eating animal products.  Normally the substance is converted into other non-damaging amino acids.  If the normal homocysteine disposal systems are faulty then homocystine can form.  This homocystine can then build up in the blood and appear in the urine.

The potential artery-damaging effects of elevated total homocysteine (tHcy) levels were suggested for many years before the substance was finally recognised as a risk factor for atherosclerotic disease.

Hyperhomocystinaemia can be due to inherited enzyme defects, various dietary deficiencies (folate and vitamins B6 and B12) or chronic renal failure.  In its most common form caused by deficiency of the enzyme cystathionine-beta-synthetase, affected individuals are normal at birth, but can develop lens subluxation, lengthening and weakening of long bones, and variable degrees of mental retardation.  These manifest during childhood and adolescence.

The presence of hyperhomocystinaemia is demonstrated by a blood test and would be commented on in the medical records.

Last reviewed for CCPS 27 April 2010.

Preliminary questions [7887]

9381     there is some evidence that hyperhomocysteinaemia may be a factor in the development or worsening of the condition under consideration.

7987     the veteran has had hyperhomocysteinaemia at some time.

26940  the veteran has established the causal connection between the hyperhomocysteinaemia and operational service for ischaemic heart disease.

7989     the veteran had hyperhomocysteinaemia before the clinical onset of the condition under consideration.

7990     the veteran has established the causal connection between the hyperhomocysteinaemia and operational service for the clinical onset of ischaemic heart disease.

or

7334     the clinical onset of the condition under consideration occurred after the end of the veteran's last period of VEA service.

7335     the condition under consideration permanently worsened.

26941 the veteran had hyperhomocysteinaemia before the clinical worsening of the condition under consideration.

26943   the veteran has established the causal connection between the hyperhomocysteinaemia and operational service for the clinical worsening of ischaemic heart disease.

Clinical onset and operational service [7990]

7992     the hyperhomocysteinaemia is causally related to operational service.

Clinical worsening and operational service [26943]

7992     the hyperhomocysteinaemia is causally related to operational service.

26945 the clinical onset of the condition under consideration occurred prior to that part of operational service to which the hyperhomocysteinaemia is causally related.