Idic 15

Also known as

  • Isodicentric 15 (Idic 15)
  • Inverted Duplication 15 (Inv Dup 15)
  • Partial tetrasomy 15q
  • Supernumerary marker chromosome 15 (SMC 15)
  • chromosome 15q11.2-13.1 duplication syndrome (Dup15q)

A rare disorder relating to Chromosome 15, which causes too much genetic material, usually in every cell in the body. For various reasons, symptoms vary greatly among individuals but can include: poor muscle tone, delayed development, impairment of motor skills (including sitting and walking), epilepsy, cognitive disability, autism.

Condition details

There are some extremely subtle common physical features but most children appear healthy and grow and look just like other children. This can mean that diagnosis is delayed because doctors often expect children with chromosome abnormalities to look unusual. Children need help with learning. Physical, occupational, and speech therapies along with special education techniques can stimulate children with Idic 15 to develop to their full potential. Speech and language therapy might help counter late development of language skills, first words might not happen until 27 months. Most will learn to speak short sentences but some children with Idic 15 will never talk. Most children with this disorder will take their first steps at 18 months. They may exhibit clumsiness which can be helped with physiotherapy. Half of babies with Idic 15 struggle to breast feed and may show signs of reflux. Careful positioning and antacid medicines might help counter this.

I would like to edit or add detail to this database entry

Photos of affected individuals

Click images to enlarge.

  • No baby imageBaby
  • No toddler imageToddler
  • No child 4-10 imageChild 4-10
  • No child 10-18 imageChild 10-18
  • No adult imageAdult

Typical age range of first manifestation

  • Can manifest in Baby
  • Does not manifest in Toddler
  • Does not manifest in Child 4-10
  • Does not manifest in Child 10-18
  • Does not manifest in Adult


Lay terms Clinical terms
  • Floppy baby syndrome Delay in reaching milestones
  • Global Development Delay
Lay terms Clinical terms
  • Autism-like symptoms such as fascination with mechanisms
  • lights
  • light switches
  • doors
  • wheels. Repetitive behaviour such as hand flapping
  • head shaking. Late crawling (>12 months)
  • late first steps (>18 months). Delayed language development (if at all).
  • Motor Stereotypies Global Development Delay
Child 4-10
Lay terms Clinical terms
  • Speech delay Learning difficulties Epileptic seizures Unusual social responses Unusual behaviour Clumsiness Autistic traits Girls go through early puberty Squints occur in about 40 per cent of children
  • these normally correct themselves with age

Affected genes identified to date

Inheritance patterns

Are carriers affected?

How many are affected?

1 in 30,000

Support groups and organisations

Dr Beverly Searle
G1 The Stables
Station Road West
Tel 01883 723356

Known experts

No experts found

I would like to edit or add detail to this database entry

Please let us know more about you

In order to allow you to edit this form, please fill in the fields below and click submit to proceed to to the editing page.

used only if we have questions about your entry.

Share this page

Welcome to the GDUK network

If this is the first time you have searched for information on a particular condition, details you find here may be distressing.

» If you would rather read our Newly Diagnosed section for parents and carers first click here