DiGeorge/Velocardiofacial Syndrome (VCFS) 22q11.2 Deletion Syndrome Info

Genetics
DiGeorge syndrome is caused by a deletion on chromosome 22.  Approximately 90% of patients with DiGeorge syndrome have a deletion at the 22q11.2 region.  A small number of cases of DGS have defects on other chromosomes, notably 10p13. DiGeorge syndrome is inherited in an autosomal dominant manner.

Incidence

  • Affects approximately 1 in 3,000 to 1 in 4,000 individuals
  • Most of the 22q11.2 deletion cases are de novo, however in about 10% of families, the deletion is inherited and other family members are affected or at risk for passing this deletion to their children
  • There is an overall 0.025% risk of the 22q11 deletion syndrome in the general population

Symptoms/Characteristics

  • Conotruncal heart defects (Tetralogy of Fallot, interrupted aortic arch, ventricular septal defects, vascular rings)
  • Palatal abnormalities
  • Feeding difficulties
  • Immunodeficiency due to absence or malformation of thymus
  • Hypocalcemia due to absence of malformation of parathyroid glands
  • Craniofacial abnormalities (see below)
  • Hearing loss or abnormal ear exams
  • Genitourinary anomalies (absent or malformed kidney)
  • Mental retardation (typically borderline to mild)
  • IQs are generally in the 70 to 90 range
  • Psychiatric disorders in adults (e.g., schizophrenia, bipolar disorder)
  • Autism

Facial Features

  • Small ears with squared upper ear
  • Hooded eyelids
  • Unilateral facial weakness
  • Small mouth, chin, and side areas of the nose tip
  • Palatal abnormalities (Cleft lip and/or palate for example)

Clinical Management

    • It is important that the immune problems in infants are identified early so that special precautions may be implemented regarding immunization and blood transfusions
    • Most treatment is directed at alleviating symptoms, infections are treated aggressively with antibiotics
    • Patients may undergo cardiac surgery for their heart abnormalities
    • Hypoparathyroidism causing hypocalcemia is often transient, but may require lifelong vitamin D treatment
    • Thymus transplantation can be used to address absence of the thymus in complete DiGeorge syndrome