Multiple carboxylase deficiency is a form of metabolic disorder involving failures of
carboxylation
Carboxylation is a chemical reaction in which a carboxylic acid is produced by treating a substrate with carbon dioxide. The opposite reaction is decarboxylation. In chemistry, the term carbonation is sometimes used synonymously with carboxylation ...
enzymes.
The deficiency can be in
biotinidase
Biotinidase (, ''amidohydrolase biotinidase'', ''BTD''), also known as biotinase, is an enzyme that in humans is encoded by the ''BTD'' gene.
The enzyme breaks down biotin amides, releasing free biotin and the amine. The main substrate is bioc ...
or
holocarboxylase synthetase
Holocarboxylase synthetase (biotin—(propionyl-Coenzyme A-carboxylase (ATP-hydrolysing)) ligase)), also known as protein—biotin ligase, is a family of enzymes ({{{EnzExplorer, 6.3.4.10). This enzyme is important for the effective use of bio ...
.
These conditions respond to
biotin.
Forms include:
*
Holocarboxylase synthetase deficiency
Holocarboxylase synthetase deficiency is an inherited metabolic disorder in which the body is unable to use the vitamin biotin effectively. This disorder is classified as a multiple carboxylase deficiency, a group of disorders characterized by im ...
- neonatal;
*
Biotinidase deficiency
Biotinidase deficiency is an autosomal recessive metabolic disorder in which biotin is not released from proteins in the diet during digestion or from normal protein turnover in the cell. This situation results in biotin deficiency.
Biotin is ...
- late onset;
If left untreated, the symptoms can include feeding problems,
decreased body tone, generalized
red rash with skin exfoliation and
baldness
Hair loss, also known as alopecia or baldness, refers to a loss of hair from part of the head or body. Typically at least the head is involved. The severity of hair loss can vary from a small area to the entire body. Inflammation or scarri ...
,
failure to thrive
Failure to thrive (FTT), also known as weight faltering or faltering growth, indicates insufficient weight gain or absence of appropriate physical growth in children. FTT is usually defined in terms of weight, and can be evaluated either by a low ...
,
seizure
An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with l ...
,
coma
A coma is a deep state of prolonged unconsciousness in which a person cannot be awakened, fails to respond normally to painful stimuli, light, or sound, lacks a normal wake-sleep cycle and does not initiate voluntary actions. Coma patients exhi ...
,
developmental delay
Global developmental delay is an umbrella term used when children are significantly delayed in their cognitive and physical development. It can be diagnosed when a child is delayed in one or more milestones, categorised into motor skills, speech, ...
, foul smelling urine,
lactic acidosis
Lactic acidosis is a medical condition characterized by a build-up of lactate (especially -lactate) in the body, with formation of an excessively low pH in the bloodstream. It is a form of metabolic acidosis, in which excessive acid accumulates d ...
, and high levels of
ketones
In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bon ...
and
ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogeno ...
in the blood.
References
External links
* http://www.pmh.health.wa.gov.au/services/newborn/health_professionals/disorders/mcd_prof.htm
Vitamin, coenzyme, and cofactor metabolism disorders
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