Velocardiofacial Syndrome

Updated: Feb 13, 2014
  • Author: M Silvana Horenstein, MD; Chief Editor: Howard S Weber, MD, FSCAI  more...
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Overview

Background

Velocardiofacial syndrome (VCFS) is a genetic condition characterized by abnormal pharyngeal arch development that results in defective development of the parathyroid glands, thymus, and conotruncal region of the heart. Shprintzen and colleagues first described the syndrome in 1978. [1] More than 180 different clinical features are associated with velocardiofacial syndrome, with no single anomaly present in every patient. Some abnormalities are more common than others. Affected individuals may present with structural or functional palatal abnormalities, cardiac defects, unique facial characteristics, hypernasal speech, hypotonia, and defective thymic development.

An estimated 75% of patients with velocardiofacial syndrome have cardiac anomalies. [2] The cardiac defects are usually of the conotruncal type, which occur secondary to abnormal development of the outflow portion of the developing heart. The most common cardiac defects include interrupted aortic arch type B (50%), truncus arteriosus (34.5%) and tetralogy of Fallot (16%). Other cardiac defects include pulmonary atresia with ventricular septal defect, absent pulmonary valve syndrome, ventricular septal defect (especially when accompanied by aortic arch anomalies), aortic stenosis, anomalies of the aortic arch or its major branches, and pulmonary artery anomalies. [3] The presence of an aortic arch anomaly increases the odds of having a 22q11.2 deletion, regardless of the intracardiac anatomy.

Palatal abnormalities predispose to speech and feeding difficulties.

The defective thymic development is associated with impaired immune function. This condition not only predisposes to an increased risk of infection but also predisposes some individuals to develop autoimmunity. Parathyroid and immune deficiencies can progress or resolve with time. [4, 5]

In addition, affected individuals may present with learning disabilities, overt developmental delay, psychiatric disorders, and renal and musculoskeletal defects.

Ophthalmologic abnormalities are seen in 70% of patients with velocardiofacial syndrome, such as posterior embryotoxon, bilateral cataracts, tortuous retinal vessels, and small optic disks. Other rare anomalies include congenital absence of the nasolacrimal duct. [6]

About 10% of patients with velocardiofacial syndrome have DiGeorge syndrome, which consists of at least 2 of the following features:

  • Conotruncal cardiac anomaly
  • Hypoparathyroidism, hypocalcemia
  • Thymic aplasia, immune deficiency

As many as 15-20% of patients have Pierre Robin syndrome, which includes small jaw, U-shaped cleft palate, and glossoptosis. Reports indicate that some patients with velocardiofacial syndrome may be mistakenly categorized as having CHARGE syndrome (ie, coloboma, heart defect, atresia choanae, retarded growth and development, and/or CNS anomalies, genital hypoplasia, and ear anomalies and/or deafness). Velocardiofacial syndrome is a specific syndrome that includes as part of its phenotypic spectrum the DiGeorge sequence, the Pierre Robin sequence, and disorders associated with CHARGE syndrome.

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Pathophysiology

This congenital disorder is caused by a deletion (microdeletion) at the q11.2 band, which is located on the long arm (q) of chromosome 22 (see the images below). This microdeletion causes an abnormality of morphogenesis that, in part, affects the migration of the neural crest cells and the early development of branchial arches.

Chromosomal fluorescence in situ hybridization (FI Chromosomal fluorescence in situ hybridization (FISH) demonstrating the deletion of one chromosomal region 22q11 segment.
Karyotype of a patient with a deletion of chromoso Karyotype of a patient with a deletion of chromosome region 22q11. Complete karyotype is shown along with an enlargement of an image of chromosome 22 demonstrating the deletion.

In 90% of cases, the disorder occurs as the result of a new mutation in the form of a de-novo 3-megabase microdeletion or translocation. This 3-megabase microdeletion encompasses a region that contains 40 genes. [7] These genes have a role in organ development, including the heart and the CNS. These genes likely affect coronary artery development, given the number of coronary artery abnormalities associated with conotruncal defects. [8]

In 10% of cases, the disorder is inherited from a parent in an autosomal dominant fashion.

The 22q11.2 microdeletion is more common in patients with aortic arch or major aortic branch vessel or pulmonary vessel anomalies. [3] Therefore, these patients should undergo genetic testing. However, a wide spectrum of clinical findings is reported among subjects with the 22q11.2 deletion, without genotype or phenotype correlation, even among affected family members and between patients with identical deletions. [9, 10, 11]

Patients have a 50% chance of passing velocardiofacial syndrome to each offspring. The microdeletion is detectable with current cytogenetic and fluorescence in situ hybridization (FISH) techniques.

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Epidemiology

Frequency

United States

The prevalence of velocardiofacial syndrome in the United States is approximately 1:2,000. [7]

International

Velocardiofacial syndrome occurs in 1 per 4000 births worldwide, according to estimates. Among those with conotruncal heart defects, the incidence is 10-30%. Among those with cleft palate without an associated cleft lip, the frequency of velocardiofacial syndrome is 8%.

Mortality/Morbidity

Those without serious heart defects can expect a normal lifespan.

Truncus arteriosus, absent pulmonary valve syndrome, and interrupted aortic arch type B are the most serious defects. Surgical correction, which must be performed in the infant, carries a higher risk. Unrecognized hypocalcemia can be associated with seizures.

Abnormal vessel course can increase morbidity. For example, abnormal course of the internal carotid arteries and other blood vessels in the pharynx can create a significant surgical risk during pharyngoplasty for velopharyngeal incompetence. An anomalously oriented ascending aorta may cause severe left main bronchus obstruction secondary to external compression. [12]

Complete DiGeorge syndrome with total absence of the thymus and a severe T-cell immunodeficiency accounts for less than 0.5% of patients with velocardiofacial syndrome. Instead, most patients with 22q11.2 deletion syndromes have partial defects with impaired thymic development with variable defects in T-cell numbers. In these patients, immunodeficiency may also be secondary to proliferative responses. In addition, humoral deficiencies have also been identified, and this particular group of patients is at increased risk of developing various autoimmune diseases. [10] Patients with sufficient CD4(+) T cells but low numbers of cytotoxic CD3(+)CD8(+) T cells are more susceptible to noncardiac mortality secondary to lymphoproliferative disorders and lethal infections. [13]

Complications

Complications include the following:

  • Congestive heart failure
  • Pulmonary hypertension
  • Immune deficiency (cellular and humoral) with increased risk of infection and autoimmune diseases
  • Psychiatric disorders

Race

No racial predilection is noted.

Sex

No sexual predilection is observed.

Age

Velocardiofacial syndrome is present at birth but may not be recognized until childhood or later. A heart defect or overt cleft palate may be detected prenatally or at birth. A submucous cleft palate, velopharyngeal incompetence (VPI), or speech and developmental delay may not be recognized until the child is older than 1 year. Hypernasal speech is common. Learning disorders and psychiatric illness may become apparent between school age and adulthood.

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