Phenylketonuria is an inherited condition caused by a deficiency in the enzyme phenylalanine hydroxylase. When untreated, it can result primarily in mental retardation. Dietary restrictions must be maintained through the lifetime of an affected individual to ensure a good outcome.
Medium-chain acyl-CoA dehydrogenase deficiency (MCAD)
In patients with MCAD the body is unable to use fat as an energy supply and any medical complications should be preventable once diagnosis and management are established.
Maple syrup urine disease (MSUD)
MSUD is a disorder in the body’s ability to use three of the essential amino acids in protein. This disease presents very dramatic signs in the newborn period such as poor feeding, lethargy or convulsions occurring within the first few days of life.
Glycogen storage disease (GSD)
GSD is a deficiency of any of the enzymes responsible for forming or releasing glycogen. Glycogen is needed by the body during exercise and/or between meals. There are many forms of GSD and they affect the liver and the muscles. The mainstay of treatment of GSD is frequent feeding.
Galactosaemia is a rare genetic metabolic disorder that affects an individual's ability to metabolise the sugar galactose properly. Patients are on a lactose free, low galactose diet.
Organo and amino acidopathies
Organo and amino acidopathies refers to a range of conditions causing problems in the breakdown of protein.
Urea cycle defects
Urea cycle defects are genetic disorders caused by a deficiency of one of the enzymes in the urea cycle which is responsible for removing ammonia from the blood stream.
Familial hypercholesterolaemia (FH)
FH is a condition in which levels of particular lipids or lipoproteins are abnormally raised in the blood. Very often several family members are affected.
Congenital disorders of glycosylation (CDG)
CDG is a novel group of rare metabolic diseases caused by defects in protein glycosylation. The defects can result in mental retardation, severe disease and physical handicap.
Lysosomal storage disorders (LSD)
LSDs are due to different enzyme deficiencies in the breakdown of complex molecules.
The lack of certain enzymes causes a build up of the substance that the enzyme would normally eliminate. This can result in abnormal storage and can cause inefficient functioning and damage of the body's cells, which can lead to serious health problems.
Examples of lysomal storage disorders include Fabry disease which causes kidney and heart problems, pain and skin rash; Gaucher disease which causes the spleen to enlarge, anaemia and bone lesions if untreated and Hurler syndrome which causes deformities of the skeleton and facial features, mental retardation and deafness.
Others include Niemann-Pick B disease which leads to enlargement of the spleen and liver, as well as lung disease; Pompe disease, where glycogen builds up in the liver, heart and muscle, especially during infancy and Tay-Sachs disease which is a lysosomal storage disease that causes degeneration of the brain in infants.
Information for Children and Families
Visit our children and families section for more health advice and information about the conditions we treat, and read, watch or listen to real stories from our parents and families.
For information and advice, independent of the hospital, please contact the national information and advice centre for metabolic diseases (Climb).
Climb is committed to fighting metabolic diseases through research, awareness and support. They are a dedicated organisation, providing advice, information and support on all metabolic diseases for children, young adults, families, carers and professionals. Climb can be contacted on 0800 652 3181 (Monday-Friday 10.00am to 3.00pm only).
Another helpful and comprehensive source is the Climb website.
For information on conditions and treatments please see our comprehensive list of jargon-free information sheets written by clinicians at Great Ormond Street Hospital (GOSH) or Parents First for Health for features, advice columns, parent stories and further condition information sheets by medical experts.
Information for children aged 7-11 years
For information on conditions and treatments please see our comprehensive list of jargon-free information sheets written by clinicians at GOSH or visit our children's section for child-friendly health advice, real life stories and further condition information sheets by our medical experts.
Information for young people aged 12-18 years
For information on conditions and treatments please see our comprehensive list of jargon-free information sheets written by clinicians at GOSH, or visit our teens section for teen-friendly health advice, real life stories and further condition information sheets by our medical experts.