How is Rett syndrome diagnosed? What can you expect is a diagnosis of Rett syndrome is a possibility?

The majority of children who have Rett syndrome do have a period of near normal development from birth up to sometimes 18 months old. Often if this is your first child and you have no comparison to make it can be very hard to spot that something could be wrong. Sometimes it may be another parent or family member that sees it first but if you notice that your child isn’t meeting milestones or seems to be unable to do or say things they used to be able to, talk to your Health Visitor or GP to begin with.  Rett syndrome is rare and other more common conditions may need to be ruled out first. You may be told that your child has  ‘global developmental delay’, however this is a catch-all term when doctors haven’t found a cause for your child’s symptoms. The criteria for diagnosing Rett syndrome are clear and may be supported by a genetic test in many cases too.

The points below will give you some guidance as to what to expect next;

• If your child is assessed during their period of regression (anywhere between 9 months and 2 years old) they may be withdrawn and non-communicative.  This may lead to a misdiagnosis of Autism.  Rett syndrome is not an Autistic Spectrum Disorder (ASD).
• Ask your GP for a blood test for Rett syndrome.  This genetic test looks for the mutation on the MECP2 gene – the most common cause of Rett syndrome. The test will either come back as positive or negative.
• You may be told the test results over the phone and given little information about the implications of either a positive or negative result.  Call our Support Helpline on 01582 798910 and we can go through the information with you and advise you on what to do next.
• A negative blood test means that your child does not have the MECP2 mutation that causes ‘Classic’ Rett syndrome.  However, they could have ‘Atypical’ Rett syndrome or a different genetic mutation that hasn’t yet been linked to Rett.  Seek a clinical diagnosis.
• Ask your GP to refer you to a specialist (usually a paediatrician) for a clinical diagnosis.  The paediatrician will observe your child and ask them/encourage them to do age appropriate tasks e.g. picking up a pencil or small object with two fingers (a pincer grip). There is a checklist for this observation and if your child ticks enough boxes, then you will receive a clinical diagnosis of Rett syndrome.
• A clinical diagnosis is just as valid as a genetic diagnosis (via blood tests). Depending on the age of your child, you may already have a physiotherapist, music therapist or take your child to hydrotherapy.  If you don’t, ask your Health Visitor, GP or Social Worker how best to access services in your local area.

Diagnostic Criteria

In 2010 Jeff Neul and his team in the USA revised the criteria for diagnosing Rett syndrome.  Click here to download the full paper.  As well as listing the physical symptoms clinicians will be looking for in a clinical diagnosis, it also goes into some detail on the variants of Rett syndrome – Atypical, Preserved Speech and Congenital Rett syndrome. This a medical publication and can be quite technical in parts so please call us if there is anything you are unsure about.

Rett UK has over 30 years experience of providing support to families and professionals. You are not alone and help is only  a phone call away.