Across all MPS diseases the brain is affected differently. The degree to which the brain is affected depends on the specific mucopolysaccharide that is either stored in the brain where symptoms become apparent or not stored in the brain where there are no symptoms Specific features for each MPS disease are below, or use the side bar to navigate to each disease.
Brain
MPS I Hurler, Hurler-Scheie and Scheie
In general, the spectrum of disease with MPS I varies from severe development delay and profound, progressive intellectual disability in Hurler disease to normal or near normal intelligence in Hurler-Scheie and Scheie disease.
Hurler disease
For children with Hurler disease intelligence is affected and without treatment, skills learnt will eventually be lost. As children with Hurler disease begin to lose skills they learnt, such as the ability to speak, they may continue to understand and find enjoyment in life. Over time, the part of the brain which regulates body temperature becomes damaged, this leads to sweating and cold hands and feet and poor temperature control.
Hurler-Scheie and Scheie disease
Due to the variation in how MPS I can affect people it means some who are on the spectrum between Hurler and Hurler-Scheie Disease may be of normal intelligence, but some will have moderate learning difficulties. For people with Scheie disease there is no storage of mucopolysaccharides in the brain and they are usually of normal intelligence.
Some people with MPS I may experience hydrocephalus, which is water on the brain. This can happen because the fluid that protects and circulates around the brain and spinal cord may become blocked over time. The blockage causes increased pressure in the head which can press on the brain causing headaches and delayed development. Tests to confirm hydrocephalus can be done using a CT or MRI scan, or a lumbar puncture. If hydrocephalus is confirmed it can be treated by an insertion of a small tube in the spinal cord which drains fluid from the brain.
MPS II Hunter
People with severe MPS II usually experience progressive storage of mucopolysaccharides in the brain that is primarily responsible for the slowing of intellectual development by 2 to 4 years of age. This is often followed by a gradual loss of skills until death however the pattern is very varied. People with less severe MPS II may have normal intelligence.
Some children will only learn to say a few words while others learn to walk well and to read a little. Children can enjoy nursery rhymes and simple puzzles and emphasis is placed on helping infants and children to learn as much as they can before the disease progresses.
A number of people who are severely affected by MPS II will develop epilepsy. There are different forms of epilepsy e.g. absence episodes where the person may appear to be staring into space with or without jerking or twitching movements of the eye muscles, or more generalised tonic-clonic seizures, a type of generalized seizure that affects the entire brain. Tonic-clonic seizures are more commonly associated with epilepsy. Most people will respond well to anticonvulsant medication.
Some people with MPS II may experience hydrocephalus, which is water on the brain. This can happen because the fluid that protects and circulates around the brain and spinal cord may become blocked over time. The blockage causes increased pressure in the head which can press on the brain causing headaches and delayed development. Tests to confirm hydrocephalus can be done using a CT or MRI scan, or a lumbar puncture. If hydrocephalus is confirmed it can be treated by an insertion of a small tube in the spinal cord which drains fluid from the brain.
MPS III Sanfilippo
Whilst the majority of children affected by MPS III will lose their intellectual ability progressively through childhood, a small number may retain intellectual skills into adulthood. Early mental and motor skill development may be delayed to a degree. Children show a marked decline in learning from 2 years of age, followed by eventual loss of language skills. Some children may never learn to speak. Aggressive behaviour, hyperactivity, profound dementia and irregular sleep may make children difficult to manage, particularly those who retain normal physical strength.
MPS III is marked by severe symptoms of the brain, these can include progressive dementia, aggressive behaviour, hyperactivity, seizures, and an inability to sleep for more than a few hours at a time. MPS III affects children differently and its progress will be faster in some than in others.
A number of people who are severely affected MPS III will develop epilepsy. There are different forms of epilepsy e.g. absence episodes where the person may appear to be staring into space with or without jerking or twitching movements of the eye muscles, or more generalised tonic-clonic seizures, a type of generalized seizure that affects the entire brain. Tonic-clonic seizures are more commonly associated with epilepsy. Most people will respond well to anticonvulsant medication.
Advice for professionals
We want to give you the tools to be able to learn about MPS, Fabry and related diseases in order for children with the condition to receive a faster diagnosis.
MPS IV Morquio
There is no storage of mucopolysaccharides in the brain of people with MPS IV and therefore intelligence is not usually affected.
MPS VI Maroteaux-Lamy
Intelligence is not affected by the disease and learning difficulties are not necessarily a feature of MPS VI, many children are above average ability.
MPS VII Sly
Deterioration of the brain is one of the main features of the severe form of MPS VII, people with the less severe form of the disease may not be affected in this way. People with severe MPS VII usually experience progressive storage of mucopolysaccharides in the brain that is primarily responsible for the slowing of intellectual development by 1 to 3 years of age. This is often followed by a gradual loss of skills until death however the pattern is very varied. People with less severe MPS VII disease may have normal intelligence.
Some children may only learn to say a few words while others learn to walk well and to read a little. Children can enjoy nursery rhymes and simple puzzles and emphasis is placed on helping infants and children to learn as much as they can before the disease progresses.
Some people with MPS VII may experience hydrocephalus, which is water on the brain. This can happen because the fluid that protects and circulates around the brain and spinal cord may become blocked over time. The blockage causes increased pressure in the head which can press on the brain causing headaches and delayed development. Tests to confirm hydrocephalus can be done using a CT or MRI scan, or a lumbar puncture. If hydrocephalus is confirmed it can be treated by an insertion of a small tube in the spinal cord which drains fluid from the brain.
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