This fact sheet provides information about Lysosomal Storage Disorders, their diagnosis, signs and symptoms and treatment.

 

Lysosomal Storage Disorders

Lysosomal storage disorders are a group of inherited metabolic disorders that arise due to a lack of one of the lysosomal enzymes which act in the body to break down certain fats and sugars. They are typically multisystem and progress over time, with the deficiency leading to a build-up of toxic material in the body.

There are over 40 lysosomal storage disorders, and they affect different body organs and tissues.

Diagnosis

Usually lysosomal storage disease is detected either during pregnancy or in newborns. This can be achieved by:

  • Prenatal genetic testing via amniocentesis or chorionic villus testing in families that have a history of lysosomal storage disease
  • Physical examination by the doctor of newborn, or young child
  • Testing for enzyme deficiencies in the blood, urine, or tissue

Signs and Symptoms

  • Vary by disease (see below)

Treatment

  • There is no cure for lysosomal storage disorders at this point in time
  • There are treatments available for some lysosomal storage disorders that can improve quality of life
  • Enzyme replacement therapy- is available for some lysosomal storage disorders and involves replacing the deficient enzyme with an artificial form intravenously.

Types specific to section 24 of the NDIS Act

 

Gaucher disease types 2 and 3

Gaucher disease is the most common type of lysosomal storage disorder. The enzyme that is deficient is called glucocerebrosidase that is responsible for breaking down a type of fat called glucocerebroside in the body. It results in the build-up of fatty lipid deposits in certain organs, particularly the spleen and liver, and bone marrow.

Gaucher disease type 2 occurs in newborns and infants and usually causes life-threatening medical issues. It is characterised by neurological problems including muscle spasms, difficulty with swallowing, and loss of motor skills over time. It is rare, and is usually fatal within the first 2 years of life.

Gaucher disease type 3 also affects the nervous system, however it has a slower progression than type 2. It varies in severity and is also rare. The life expectancy of a person who has type 3 gaucher disease is approximately 20-40 years.

Signs and symptoms

  • Swollen appearing belly from spleen and liver enlargement
  • Skeletal abnormalities: bone pain, bones that fracture more easily, as well as slow bone growth, and bone necrosis (death of the bone tissue)  
  • Anaemia and fatigue- lack of energy, and tired even after a full nights sleep
  • Bleeding and bruising issues- increased tendency to bleed such as nose bleeds and bruising due to a decrease in platelet levels.

Niemann-pick disease [types A and C]

Niemann-pick disease is a group of inherited disorders related to fat metabolism. People who have Niemann-pick disease types A and C experience progressive decline in motor skills, difficulty with feeding, progressive learning difficulty, and seizures. It affects approximately 1 in 250, 000 individuals.

Signs and Symptoms

  • Balance problems- clumsiness, difficulty walking
  • Increased muscle contractions
  • Difficulty sleeping
  • Difficulty swallowing and eating resulting in poor growth
  • Cherry-red spot on the inside of the eye (on the macula)
  • Recurrent pneumonia

People with type A will generally show signs and symptoms within the first few months of life, whereas those with type C may not show any signs and symptoms until adulthood.

Type A is caused by a malfunction of the enzyme sphingomyelinase which affects the bodys ability to metabolise fat. There is no cure and children with niemann-pick type A do not generally live past their first few years of life.

Type C is a rare form of niemann-pick disease and causes an accumulation of fats in the liver, spleen, or lungs. The brain may eventually be affected also.

Pompe disease

Pompe disease has both an infantile and a delayed onset form. Infantile form is the most severe, and though infant appears healthy at birth, the disease usually presents between 2 weeks and 3 months with rapidly progressing muscle weakness. The disease is caused by a mutation in the GAA gene, which is responsible for the development of an enzyme called acid alpha-glucosidase. The role of this enzyme is to break-down glycogen into a simpler sugar called glucose, and therefore a deficiency leads to a build-up of glycogen in certain organs and tissues, affecting their ability to function normally. It affects approximately 1 in every 40, 000 births.

Signs and symptoms

Infantile-onset Pompe disease

  • Muscle weakness
  • Decreased muscle tone
  • Delay in motor skill development
  • Enlarged liver
  • Heart defects
  • Poor growth
  • Problems with breathing

Late onset Pompe disease

  • Progressive muscle weakness, particularly in legs and trunk
  • Difficulty breathing
  • Fatigue
  • Abnormal spine curvature

Sandhoff disease [infantile form]

The infantile form of sandhoff disease usually presents between the ages of three and six months. It is a rare inherited disorder caused by a problem with the HEXB gene which is responsible for the production of two enzymes in the nervous system: beta-hexosaminidase A and beta-hexosaminidase B. These enzymes ordinarily breakdown a fatty substance called GM2 ganglioside, and a deficiency of these enzymes therefore leads to a build of this substance, which causes progressive destruction of nerve cells in the brain and the spinal cord.

Signs and symptoms

  • Slowing of development around 3-6 months of age
  • Weakened muscle movement
  • Delay or loss of motor skills such as rolling over, sitting upright, or crawling
  • Development of an exaggerated startle reaction to loud noises
  • As the disease progresses
    • Seizures
    • Hearing loss
    • Progressive cognitive/intellectual decline
    • Paralysis 

Schindler disease [type 1]

Type 1 schindler disease is the classic form which presents in infancy. Children with this disease appear to be developing normally until around 1 year of age, after which they begin to lose previously acquired skills that require coordination of physical and mental activities. It is caused by a mutation in the NAGA gene, which is responsible for the production of the enzyme alpha-N-acetylgalactosaminidase. The role of alpha-N-acetylgalactosaminidase is the breakdown glycoproteins and glycolipids, and therefore a deficiency in this gene leads to a build-up of these substance which cause cell damage in the nervous system.

Signs and symptoms

  • Stop developing new skills and lose previously acquired skills around 8 to 15 months of age (developmental regression)
  • Development of blindness and seizures
  • Eventual loss of awareness of surroundings and become unresponsive
  • Muscle weakness
  • Development of visual impairment

 

Tay-sachs disease [infantile form]

There are two forms of tay-sachs disease; classic form which is infantile and late-onset form.

Infantile form of tay-sachs will typically present between three to five months of age, and is characterised by rapid motor delays and progressive cognitive deterioration. Tay-sachs disease is caused by a mutation in the HEXA gene, which is responsible for the development of an enzyme called beta-hexosaminidase A. Usually beta-hexosaminidase A breaks down a fatty substance called GM2 ganglioside, and a build-up in this substance due to a beta-hexosaminidase A deficiency leads to damage of neurons in the nervous system.

Signs and Symptoms

  • Slowing of development around 3-5 months of age
  • Muscle weakness
  • Loss of previously acquired motor skills
  • Exaggerated startle reaction to loud noises
  • Slowed growth
  • As the disease progresses
    • Seizures
    • Visual and hearing loss
    • Difficulty swallowing
    • Cherry-red spot on the macula of the eye
    • Deterioration in cognitive/intellectual ability

References:

Lysosomal Storage Disorders - NORD (National Organization for Rare Disorders). (2019). Retrieved from https://rarediseases.org/rare-diseases/lysosomal-storage-disorders/

Gaucher Disease (2019). Retrieved from https://ghr.nlm.nih.gov/condition/gaucher-disease#diagnosis

Gaucher Disease (2019). Retrieved from https://www.gaucherdisease.org/about-gaucher-disease/what-is/

Gaucher Disease (2019). Retrieved from https://brainfoundation.org.au/disorders/gaucher-disease/

Niemann-pick Disease (2019). Retrieved from https://ghr.nlm.nih.gov/condition/niemann-pick-disease#diagnosis

Niemann-pick Disease (2019). Retrieved from https://rarediseases.info.nih.gov/diseases/7206/niemann-pick-disease-type-a

Pompe Disease (2019). Retrieved from https://ghr.nlm.nih.gov/condition/pompe-disease#diagnosis

Pompe Disease (2019). Retrieved from https://rarediseases.org/rare-diseases/pompe-disease/

Sandhoff Disease (2019). Retrieved from https://ghr.nlm.nih.gov/condition/sandhoff-disease#genes

Sandhoff Disease (2019). Retrieved from https://rarediseases.info.nih.gov/diseases/7604/sandhoff-disease

Schindler Disease (2019). Retrieved from https://ghr.nlm.nih.gov/condition/schindler-disease#genes

Schindler Disease (2019). Retrieved from https://rarediseases.info.nih.gov/diseases/116/schindler-disease-type-1

Schindler Disease (2019). Retrieved from https://rarediseases.org/rare-diseases/schindler-disease/

Tay-sachs Disease (2019). Retrieved from https://ghr.nlm.nih.gov/condition/tay-sachs-disease#genes

Tay-sachs Disease (2019). Retrieved from https://www.nhs.uk/conditions/tay-sachs-disease/