-
Presence of acyl-carnitines in the blood:
patients with MCAD
deficiency have more acyl-carnitines with 8 carbons (C8) in their
blood. Also the levels of acyl-carnitines of length C6 and C10 are
elevated. See also the chapter about newborn screening.
-
Presence
of fatty acids in the blood: patients with MCAD deficiency have a
higher concentration of fatty acids in their blood, especially medium
chain fatty acids with 8 or 10 carbons. This is because these fatty
acids can not properly be oxidized in the process of beta-oxidation.
See also the chapter on fat
metabolism.
- Presence of metabolites of the omega-oxidation
in the urine combined
with an abnormal low amount of ketone bodies in the urine: if
beta-oxidation is not properly working, the body has an other process
for fatty acid oxidation. This process is called the omega-oxidation.
This omega-oxidation process will not help patients with MCAD
deficiency because the rest product of omega-oxidation still has to be
processed by the beta-oxidation. The omega-oxidation will also leave
specific metabolites in the urine of the patient. These metabolites are
called dicarboxylic acids. Again mostly those of length C6, C8 and C10
are elevated.
In a normal person ketone bodies would be found when
fat is metabolised for energy. In patients with MCAD deficiency these
ketone bodies can not be properly formed, so their presence in the
urine can be abnormally low. See also the chapter about the fed-fast cycle
for more information about the formation of ketone bodies.