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22q11 Deletion syndrome

Also known as: Di George syndrome, Conotruncal Anomaly Face syndrome, 2q11.2 Deletion syndrome, Velo-cardio-facial syndrome, Shprintzen syndrome

Background

22q11 deletion syndrome is caused by a small deletion in position 11 on the long (q) arm of chromosome 22. Other names may be used, listed above, reflecting the preference of the specialists advising. 22q11 deletion occurs in around 1 in 4,000 of the population, although research suggests it could be as common as 1 in 1,000. The very variable ways it affects individuals can result in a lengthy time to obtain a diagnosis.

Credits

Medical text written December 2011 by Dr A Habel. Last updated May 2016 by Dr A Habel, Honorary Consultant Paediatrician, Great Ormond Street Hospital, London, UK.

Although great care has been taken in the compilation and preparation of all entries to ensure accuracy, we cannot accept responsibility for any errors or omissions. Any medical information is provided is for education/information purposes and is not designed to replace medical advice by a qualified medical professional.

 

What are the symptoms?

Features of 22q11 deletion syndrome include:

  • heart problems − including tetralogy of Fallot (see entry Heart Defects), interrupted aortic arch, ventricular septal defect and right aortic arch
  • learning disabilities (see entry Learning Disability) − including slow development of speech and language and poor concentration. Attention deficit hyperactivity disorder (see entry ADHD) is more common than usual
  • velopharyngeal insufficiency (VPI) − can cause regurgitation through the nose, a 'nasal' voice and difficulty making consonant sounds
  • middle ear infections and glue ear (see entry Deafness)
  • cleft palate, rarely cleft lip (see entry Cleft Lip and/or Palate)
  • distinct facial features - including almond-shaped eyes and elongated features, flat cheek bones, a long, 'strong' nose and small jaw
  • increased risk of catching infections - caused by abnormalities in T-cells (cells in the immune system) and the thymus
  • hypocalcaemia (low blood calcium levels)
  • thyroid gland abnormality - more usually under than overactive (see entry Thyroid disorders).
  • growth can be particularly poor early on, but usually catch up in later childhood
  • immature, may behave younger than their age, prone to rapid mood swings.
  • Mental health problems. Autistic like behaviour, obsessional tendency, panic attacks, and beyond childhood, depression (see entry Depression in Children and Young People) and schizophrenia are more common than usual
  • kidney - including an absent kidney, kidney cysts, or one kidney smaller than the other
  • bone and muscle - scoliosis (curvature of the spine) in later childhood, club foot (see entry Lower Limb Abnormalities) and juvenile rheumatoid arthritis. Reduced muscle tone, hypermobile joints, and lower limb pains, are common
  • long sightedness
  • laryngeal webbing - (an additional piece of tissue in the throat) may cause breathing difficulties from birth.

 

What are the causes?

In 22q11 deletion syndromes, each chromosome has a long (q) and short (p) arm. In this syndrome a tiny part is missing (deleted) from the long arm (q) of one of the two chromosomes 22's at position 11 on that chromosome.

How is it diagnosed?

The fluorescence in-situ hybridisation (FISH) test is one method available, which identifies 95% of people with the deletion. Newer DNA tests such as array CGH(comparative genomic hybridisation)  on a small amount of blood, allow much quicker diagnosis than in the past, and are now available in many parts of the UK.

 

How is it treated?

Although there is no cure, treatment can alter outcomes. As feeding difficulties in 22q11 deletion syndrome may be due to abnormalities of structure as well as function, expert assessment is necessary before treating. Structural heart conditions, cleft palate and palate insufficiency can benefit from surgery. Low calcium responds to vitamin D and calcium supplementation, and thyroid and growth hormone insufficiency responds to replacement.

A child will usually need extra support in learning and the assistance of a speech and language therapist in learning and language development. Immune deficiency requires treating infections aggressively. Rarely intravenous immunoglobulin (IVIG) therapy or transplantation of the thymus is required. Early diagnosis and early intervention for behaviour disorders and psychiatric illnesses improves their outcome.

 

Inheritance patterns and prenatal diagnosis

Inheritance patterns

In many affected children the deletion is sporadic, but in a small number (ten per cent) it is inherited from one parent. If a parent carries the 22q11 deletion, the inheritance mode is autosomal dominant. When neither parent shows the deletion there is still a one to two per cent risk of another affected child.

Prenatal diagnosis
Amniocentesis or chorionic villus sampling will detect the chromosome 22 deletion. Ultrasound scans can detect most heart defects.

 

Is there support?

Max Appeal

Helpline: 0300 999 2211
Email: via website
http://www.maxappeal.org.uk

The Appeal is a Registered Charity in England and Wales No. 1088432. It provides information and support to families affected by DiGeorge syndrome, VCFS and 22q11.2 deletion.

Group details last updated May 2016.

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