About Smith-Magenis syndrome

Smith-Magenis syndrome is a lifelong genetic condition that affects physical, cognitive and behavioural development.

It’s caused by missing genes on chromosome 17 or by changes in the RAI1 gene on chromosome 17. This genetic change happens around the time of conception. Smith-Magenis syndrome isn’t usually inherited.

Smith-Magenis syndrome is a rare condition. It occurs in 1 in 15,000-25,000 births.

Children with Smith-Magenis syndrome are often also diagnosed with autism, attention deficit hyperactivity disorder, obsessive compulsive disorder and mood disorders.

Signs and symptoms of Smith-Magenis syndrome

Physical characteristics
Children and teenagers with Smith-Magenis syndrome might have characteristic facial features that include a broad, square face with deep-set eyes, full cheeks, a prominent lower jaw, a flattened bridge of the nose, a downturned mouth and a ‘tent’-shaped upper lip.

They might also have:

• low muscle tone
• short stature with short fingers and toe
• scoliosis
• a hoarse, low-pitched voice
• vision problems like short-sightedness and crossed eyes
• flat or highly arched feet and an unusual way of walking – for example, toe-walking or walking with a broad-based gait.

Cognitive signs
Children and teenagers with Smith-Magenis syndrome might have:

• developmental delay
• mild to moderate intellectual disability
• delayed speech and communication impairment
• delayed gross motor skills and fine motor skills, including problems using the tongue, jaw, cheeks or lips, which might result in feeding difficulties in babies and poor physical growth.

Behaviour signs
Children with Smith-Magenis syndrome often have:

• chronic sleep disturbances – for example, they might be very sleepy during the day and awake frequently at night
• prolonged tantrums, explosive outbursts, sudden mood changes, aggressive behaviour and difficulty with impulse control
• anxiety
• attention difficulties
• a tendency to injure themselves deliberately – for example, head-banging and hand-biting
• repetitive behaviour – for example, hugging themselves repeatedly, rocking and verbal ticks
• reduced sensitivity to pain and temperature
• ongoing eating difficulties – for example, a preference for soft foods.

Medical concerns linked to Smith-Magenis syndrome
Children with Smith-Magenis syndrome might have medical concerns like:

• ear problems – for example, middle-ear abnormalities, chronic ear infections or hearing loss
• dental problems
• seizures
• heart and kidney defects
• retinal detachment – for example, because of head-banging
• chronic constipation.

Most children and teenagers with Smith-Magenis syndrome have excellent long-term memory, happy and endearing personalities, and a good sense of humour.

Diagnosis and testing for Smith-Magenis syndrome

Health professionals diagnose Smith-Magenis syndrome by looking at the physical and other signs and symptoms listed above. They usually confirm the diagnosis with genetic testing.

Early intervention services for children with Smith-Magenis syndrome

If your child has Smith-Magenis syndrome, early intervention is the best way to support your child’s development. Early intervention includes therapies, education and other supports that will help your child reach their full potential.

Early intervention should also include helping you learn how to spend time with your child in ways that support their development. Children learn the most from the people who care for them and with whom they spend most of their time, so everyday play and communication with you and other carers can help your child a lot.

You and your child will probably work with many health and other professionals as part of your child’s early intervention. These professionals might include behavioural therapists, occupational therapists, paediatricians, physiotherapists, psychologists, special education teachers and speech pathologists.

Working in partnership with your child’s professionals is very important. When you combine your deep knowledge of your child with the professionals’ expertise, you’re more likely to get the best outcomes for your child.

Financial support for children and teenagers with Smith-Magenis syndrome

If your child has a confirmed diagnosis of Smith-Magenis syndrome, you might be able to get support from the National Disability Insurance Scheme (NDIS). The NDIS can help you get services and support in your community. The NDIS might also fund things like early intervention therapies or one-off items like wheelchairs.

Looking after yourself and your family

It’s important to look after yourself physically, mentally and emotionally. If you take care of yourself, you’ll be better able to care for your child.

If you need support, you could start by talking with your GP. Your GP is there to give you and your child ongoing care and support.

A genetic counsellor might be able to help you understand how the change in your child’s genes happened. They can also help you learn about the condition and adapt to having a genetic condition in your family.

You can also get support from organisations like Smith-Magenis Syndrome Australia, Genetic Alliance Australia and Genetic Support Network of Victoria.

Talking to other parents can be a great way to get support too. You can connect with other parents in similar situations by joining a face-to-face or an online support group. Smith-Magenis Syndrome Australia can connect you to groups like these.

If you have other children, they might have a range of feelings about having a sibling with disability. They need to feel that they’re just as important to you as your child with disability – that you care about them and what they’re going through. It’s important to talk with your other children, spend time with them, and find the right sibling support for them.