Phosphoserine Aminotransferase Deficiency

What else is it called?

  • Psat Deficiency.

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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?

Phosphoserine aminotransferase deficiency is an extremely rare form of serine deficiency syndrome. Characterizedby low plasma and cerebrospinal fluid concentrations of the amino acids’ serine and glycine and clinically by seizures, acquired microcephaly, hypertonia, and psychomotor dysfunctions.

It is believed that this metabolic condition is caused by mutations in the PSAT1 gene which disrupts the amino acid serine and glycine’s natural anabolic  metabolism leading to a lack of this amino acids within the body.

How common is it?

To date, this metabolic condition has been diagnosed in 2 individuals worldwide. There is not enough available data to suggest whether this condition favours males or females or specific ethnicities.

What are the signs and symptoms?

Signs and symptoms may differ per individual and these symptoms are usually present from birth, below is a list of some of the most common symptoms experienced:

  • Seizures
  • Hypertonia
  • Microcephaly [small head percentile circumference]
  • Psychomotor dysfunctions.
  • Global developmental delay
  • Feeding difficulties

How is it diagnosed?

A recent study found that PSAT deficiency should be considered for children with congenital microcephaly [small head circumference], although further characterization of Magnetic resonance imaging [MRI] findings in other patients is required.

MRI is a type of scan that uses strong magnetic fields and radio waves to produce detailed images of the inside of the body, it is a painless procedure however you may experience some loud noise and banging whilst the machine is working, protective hearing aids will be offered for this. The results of an MRI scan can be used to help diagnose conditions and plan treatments.

Can it be treated?

Due to the rare nature of this condition there is no current evidence to suggest there is treatment available for this metabolic condition. Serine and glycine supplementation have been tried before with very little benefit.

Do my family need to be tested?

Some conditions are inherited in an autosomal dominant pattern such as Phosphoserine aminotransferase deficiency. In this case, only 1 parent needs to carry the mutation for the condition to be passed on to the child.

If 1 parent has the mutation, there’s a 1 in 2 (50%) chance it will be passed on to each child the couple has.

One mutated copy of the gene in each cell is sufficient for a person to be affected by an autosomal dominant disorder. In some cases, an affected person Once you are diagnosed, you can speak to a genetic counsellor. They can explain how you may have inherited Phosphoserine aminotransferase deficiency. 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 Phosphoserine aminotransferase deficiency and go on to have further children, their New-born Screening test should be carried out within 24-48 hours of birth.

inherits the condition from an affected parent. In others, the condition may result from a new mutation in the gene and occur in people with no history of the disorder in their family.

Relevant Organisations


References are available on request. Please contact Helen Morris by phoning 0845 241 2173 or emailing [Resource Library No: AAP002].

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