Handbook of Genetic Counseling/22q11 Deletion Syndrome
22q11 Deletion Syndrome (a.k.a. Velocardiofacial Syndrome (VCF), DiGeorge Syndrome)
Diagnosis
edit- Caused by a deletion of material from one copy of the long arm of
chromosome 22
- Submicroscopic deletion in DiGeorge Chromosomal Region
(DGCR)
- Chromosome banding may sometimes detect deletion
- FISH testing detects deletion in 95% of affected individuals
- Autosomal dominant inheritance
- About 94% of patients have de novo mutation
- Parents of affected individuals should have FISH testing
- Offspring of affected individual have 50% chance of inheriting 22q11 deletion
- Recurrence risk for siblings of affected individual is very small if FISH testing shows the parents do not have the deletion
- Several genes are located within the DGCR
- Some of these gene products have been identified
- Cannot predict genotype-phenotype correlation because size of
deletion does not seem to correlate with severity of characteristics Characteristic Findings:
- Congenital heart disease
- Found in about 74% of affected individuals
- Usually conotruncal malformations
- Teratology of Fallot
- Interrupted aortic arch
- Truncus arteriasis
- Ventricular septal defect (VSD)
- Conotruncal malformations identified in infancy/early childhood
and can be surgically repaired
- Mild problems with the aorta may not be recognized
- Palatal abnormalitites
- Found in about 69% of affected individuals
- Several types of abnormalities observed
- Velopharyngeal incompetence (VPI)
- Submucosal cleft palate
- Visible cleft palate
- Cleft lip and palate
- Bifid uvulae
- May be surgically repaired
- May affect speech development
- Speech therapy is recommended
- Feeding difficulties
- Found in about 30% of affected individuals
- May be due to palate or heart problems
- May also be caused by problems transporting food from the
mouth to the esophagus
- Signs of feeding difficulty
- Infants are irritable, gag, vomit, have a weak suck
- Younger children find spoon feeding easier but have trouble drinking from a cup
- Older children have difficulty with lumpy, crunchy foods
- May be treated by teaching children better feeding practices
- Signs of feeding difficulty
- Immunodeficiency
- Caused by small or missing thymus gland
- Causes greatest number of problems in first year of life
- Children may have frequent infections such as bronchitis or
pneumonia
- As children grow older, T cell production improves
- Hypoparathyroidism
- Regulates calcium levels in bloodstream
- Absence or underdevelopment leads to hypocalcemia
- May cause tremors, seizures, muscle spasms, abnormal breathing, and abnormal heart rhythms
- Diagnosed by a blood test
- Treated with calcium supplements
- Regulates calcium levels in bloodstream
- Growth hormone deficiency
- Approximately 41% of affected individuals are below the 5th
percentile in height
- May be caused by abnormalities in formation of pituitary gland
- In only about 1/10 of individuals with 22q11 deletion
- Causes reduced levels of growth factors
- Can be determined with a blood test
- Treatment with injections of growth hormones
- May be caused by abnormalities in formation of pituitary gland
- Characteristic Facial Features
- Nose - bulbous nasal tip, prominent nasal root, nasal dimple
- Ear - overfolded helices; cupped, microtic, and protuberant ears;
narrow external auditory meati
- Eyes - hooding of upper or lower lid, ptosis, epicanthal folds
- Renal anomalies
- Found in about 37% of affected individuals
- Includes single kidney, echogenic kidney, small kidneys, and other
renal anomalies
- Juvenile rheumatiod arthiritis (JRA)
- About 150 times more frequent than in general population
- Age of onset is 17 months to 5 years
- Developmental difficulties
- Found in 70-90% of affected individuals
- Development of motor skills
- Due to problems with muscle strength and coordination
- Often delayed in sitting, crawling, walking
- May be helped by physical therapy
- Learning
- Typically have slower learning rate
- Follow same learning sequence as other children but at slower pace
- Often have strong verbal skills but weaker math skills
- May have difficulty paying attention
- Early diagnosis and intervention important
- May require learning support
- Speech and language
- Verbal speech usually does not develop until 2-3 years
- May also have difficulty in formation of sounds
- Palatal problems often lead speech problems
- Early intervention by speech and language pathologist is important
- Behavioral difficulties
- About 40% of affected individuals develop psychiatric illness
- Depression
- Anxiety
- Schizophrenia
- Bipolar disorders
- May be evident as tantrums and mood swings in childhood
- Social skills training and counseling may be necessary
- About 40% of affected individuals develop psychiatric illness
Resources
edit- Cincinnati Velocardiofacial Support Group
- Teresa Paul
- 9327 Bluewing Terrace
- Cincinnati, Ohio 45236
- Email: MOTHERTP@aol.com
- Velo-Cardio-Facial Syndrome Education Foundation
- Jacobson hall Room 707
- University Hospital
- 750 East AdamsStreet
- Syracuse, NY 13210
- Phone: 315-464-6590
- Email: vcfsef@hscsyr.edu
- Web: [1]
- International DiGeorge/VCF Support Network
- c/o Family Vioces of New York
- 461/2 Clinton Avenue
- Cortland, NY 13045
- Phone: 607-753-1621 (day) 607-753-1250 (evening)
- Chromosome Deletion Outreach, Inc.
- PO Box 724
- Boca Raton, FL 33429-0724
- Phone: 561-395-4252
- Email: cdo@worldnet.att.net
- Web: [2]
References
editNotes
editThe information in this outline was last updated in 2002.