Common issues in CASK children

CASK gene disease ranges in severity, symptoms and prognosis.

Below we discuss the CASK gene medical problems that children may suffer from. Few have all of these conditions, and some may have very few.

Chewing and swallowing both require fine motor movements and complex coordination. As a result, some children struggle to feed efficiently or easily and/or may aspirate on liquids (this is when liquid goes down the trachea instead of the oesophagus). Aspiration is serious since it can cause repeat lung infections requiring antibiotics and/or hospitalisations. A minority of children have feeding tubes to ensure they stay well hydrated and get adequate nourishment

Approximately 40% of children with CASK develop epilepsy. It is important to learn the signs of seizures, particularly infantile spasms, which can exhibit subtly and, in babies, mask as reflux.

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A number of children require hearing aids. The most common form of hearing loss is sensorineural hearing loss. It is when the inner ear nerves and hair cells are damaged. It therefore affects the pathway from the inner ear to the brain. It doesn’t appear to be progressive in CASK children.

It is important to factor in the problems with doing hearing tests on children who are non-verbal and cannot express themselves.

Reflux is common CASK gene medical problem because it can be caused by low muscle tone. It can be hard to diagnose since the child is unable to articulate the pain. A typical tell-tale sign is arching of the back. Medications such as omeprazole can help or even eliminate the symptoms.
The majority of children have low muscle tone in the trunk (hypotonia) causing floppiness. In addition, there may be hypertonia (stiffness) particularly in limbs. CASK children should be assigned a physiotherapist to help with the issues associated with altered muscle tone. Signs of hypotonia include delays in physical development, weakness and hypermobility of limbs.
Cask is often associated with a vision condition called nystagmus. This is normally diagnosed easily. The eyes make repetitive, uncontrolled movements. Click here to read a question and answer session with a UK specialist.

Many CASK children have a little understood condition called CVI (cortical visual impairment). It is a decreased visual response due to the CASK condition affecting the visual part of the brain. Typically, a child with CVI has a normal eye exam or has an eye condition that cannot account for the abnormal visual behavior. It is often said that CVI is permanent, but with the right therapies the condition can be dramatically improved. Children with CASK who appear to have vision issues (including failing to make eye contact) should ideally be connected with the local visual impairment team.
Scoliosis is a sideways curve of the spine. It most often occurs during a growth spurt or just before puberty. Unfortunately, it appears quite common in CASK children and parents should be on the look out for it before puberty. It can be a very serious condition requiring braces and/or surgery.
From the NHS:

“Developmental dysplasia of the hip (DDH) is a condition where the “ball and socket” joint of the hip does not properly form in babies and young children.

It’s sometimes called congenital hip dislocation or hip dysplasia.

The hip joint attaches the thigh bone (femur) to the pelvis. The top of the femur (femoral head) is rounded, like a ball, and sits inside the cup-shaped hip socket. In DDH, the socket of the hip is too shallow and the femoral head is not held tightly in place, so the hip joint is loose. In severe cases, the femur can come out of the socket (dislocate).”

CASK children may have hip dysplasia because they are not weight bearing like their peers. Standing frames are thought to help the socket form the correct shape, since they allow for weight bearing. The NHS OT (occupational therapist) should ensure a standing frame is provided at the appropriate age.
Sleep issues are unfortunately common issues in CASK children. The part of the brain that controls sleep is affected and Melatonin is often prescribed to help the child get to sleep. Sleep is extremely important so it is appropriate for a paediatrician to offer assistance with this. It can be a long road to getting the support or medication you require so we advise families to start the journey sooner rather than later. The paediatrician is likely to request a referral to a sleep consultant and then a sleep study will be conducted. There are often long waiting lists. Melatonin is normally the first drug of choice but has limited effectiveness on children with CASK mutations. Clonadine appears to be a relatively successful medication for our children and has few if any side effects. 
Most likely a result of low tone and reduced movement, constipation can have a significant impact on a child’s well-being in addition to increasing seizure activity. There are numerous medicines to help, such as Laxido and Movicol.
Having cold extremities and/or mottled skin appears to be a common CASK phenotype. So far doctors do not have an explanation for this (other than lack of movement) and it does not seem to cause distress or be a sign of more serious underlying issues. Since the brain stem (which is commonly affected in CASK) plays a role in temperature regulation it is not surprising that some children also struggle to control their body temperature and this may explain the cold extremities.
Many children may be diagnosed with sensory processing disorder. It is a neurological disorder resulting from the brain’s inability to integrate information received from the body’s sensory systems. The individual therefore reacts in an extreme way to normal things. An example of being affected in an auditory manner is a child becoming inconsolable at the sound of a vacuum cleaner.

 

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A number of children with CASK gene mutations gain a dual diagnosis of autism. Read more from our medical advisor Dr Laura Powling.