Hereditary metabolic diseases

Hereditary metabolic diseases (HMD) are chronic progressive multi-system illnesses that may appear at any age and that in most cases pose diagnostic and therapeutic challenges. Our Unit has been recognised as a leader within Spain (CSUR) and Europe (ERN) for this pathology and takes part in the neonatal screening programme in Catalonia. We are the only centre in Catalonia to offer complete care from paediatrics to adults with particular expertise in lysosomal storage disorders.

HMDs are divided into:

- Intermediary metabolism HMD: usually with acute symptoms.

- HMD related to the organelles (lysosomal storage disorders, peroxisomal diseases, mitochondrial disorders and endoplasmic reticulum storage diseases): chronic presentation with no decompensations (with the exception of some mitochondrial disorders)

Multiple systems in the body are affected and different organs and systems are involved with varying symptoms depending on the disorder and the patient’s age. These disorders require a coordinated approach to care and programmes to manage the transition to adulthood. 

Symptoms

Many symptoms become evident during childhood in the form of delayed physical growth and delayed psychomotor development. There may be associated heart problems, kidney conditions, and at times decompensations leading to liver or kidney failure and neurological impairment. In the case of organelle disorders, symptoms are chronic and affect the bones and organs of the senses in greater measure. They are more common in adults than intermediary metabolism disorders.   

Diagnosis

Diagnosis is carried out by:

• Laboratory tests: biochemical and enzyme analysis on different tissues according to the suspected diagnosis.
• Specific genetic testing to confirm diagnosis

Treatment 

They are chronic disorders that need to be treated in specialised centres with multidisciplinary teams to provide support for all related health problems.

The following may be necessary, depending on the type of disorder:

• A special and complex diet with different supplements and cofactors
• Pharmaceuticals that help avoid build up of toxic substrates
• Highly complex medication such as enzyme replacement therapy or substrate inhibitors
• Stem cell, liver or kidney transplant 

Prevention

Prevention consists of thorough genetic and reproductive counselling if there is a family history of the disease. Early diagnosis of some diseases through the neonatal screening programme enables effective treatment and improved prognosis.