Methylglutaconic Aciduria Type lV

What else is it called?

  • MGA4

Get in touch

Contact our caring team on 08452 412 173 for help and support. Our phone lines open 10am-4pm, Monday to Friday.

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What causes it?

MGA4 is an autosomal recessive condition which belongs to a group of 5 different conditions of the 3-methylglutaconyl aciduria known as organic aciduria disorders, all of which effect the body’s mitochondria where energy is produced. Due to the rareness of this condition it has not yet been quantified which gene is responsible for this metabolic disorder.

This condition is believed to affect an area of the brain called the cerebellar due to hypoplasia of this region which can have harmful effects on the body.

How common is it?

Due to the rareness of this condition, the prevalence of this condition cannot be determined nor can if this condition is more prevalent in females or males or specific ethnicities.

What are the signs and symptoms?

Symptoms of this condition may become apparent from the neonatal period of infancy; however, a diagnosis may not be made until childhood due to the similarity of symptoms to other metabolic conditions, below are a list of more common symptoms you may expect to see with this condition:

  • Neurological problems
  • Failure to thrive from birth
  • Hypotonia [muscle weakness]
  • Respiratory distress
  • Hearing loss
  • Seizures, developing in infancy

Previous literature also suggests that dysmorphic features may be apparent with this condition, these have been said to occur as the condition progresses. This can be characterised as longing of the face due to muscle loss and long prominent ears. Some of the other features described with this condition are comparable to that of Barth syndrome such as a tall forehead and curved eyebrows.

How is it diagnosed?

Clinical diagnosis can be made via blood analysis or by urinalysis from a 24-hour urine collection or random 1 off urine sample. patients who share mild or intermittent urinary excretion of 3-methylglutaconic acid along with the specific symptoms may be a diagnostic method for this condition. MRI scans are also used to determine if there is any distress and abnormalities within the regions of the brain associated with this order, this method can provide further clarification for the diagnosis of 3-MGA type IV. MRI scans are a painless procedure; however, they can be rather loud, but ear protection should be offered. If you are claustrophobic about MRI scans, then let the health care assistants aware on the day and this procedure can be made more comfortable for you possibly through an open MRI scan.

In some countries the new born screening test for this metabolic condition may be available, this involves a heel prick test from your babies heel approximately 6-8 weeks after birth to test for different conditions, this is more likely to be tested if this condition is present within your family history.

Can it be treated?

At present there is no effective treatment for 3-MGA type IV, treatment is usually aimed at managing symptoms as they emerge. Research had previously looked at the effects of a leucine-restricted diet however, this appears to be of no benefit.

Do my family need to be tested?

MGA4 can only be passed on to a child if both parents have a copy of the faulty gene. This is called autosomal recessive inheritance. A person who has a copy of the faulty gene is known as a carrier.

If both parents are carriers, their child has a one in four (25%) chance of inheriting the disorder, and a one in two chance (50%) of being a carrier. This is the same for each child the parents have.

If the child only inherits one copy of the faulty gene, they will be a carrier but will not have the disorder. In some rare cases, carriers have had mild symptoms of the disorder for which they carry the faulty gene.

Once you are diagnosed, you can speak to a genetic counsellor. They can explain how you may have inheritedMGA4. They can also tell you about genetic testing for the rest of your family. They can provide advice and support if you go on to have children of your own.

If you have previously had a child with MGA4 and go on to have further children, their New-born Screening test should be carried out within 24-48 hours of birth.

Relevant Organisations

References

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