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DiGeorge Syndrome

(22q11.2 Deletion Syndrome)

By

James Fernandez

, MD, PhD, Cleveland Clinic Lerner College of Medicine at Case Western Reserve University

Last review/revision Jan 2023
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DiGeorge syndrome is thymic and parathyroid hypoplasia or aplasia leading to T-cell immunodeficiency and hypoparathyroidism. Infants with DiGeorge syndrome have low-set ears, midline facial clefts, a small receding mandible, hypertelorism, a shortened philtrum, developmental delay, and congenital heart disorders. Diagnosis is based on clinical findings and includes assessments of immune and parathyroid function and chromosome analysis. Treatment includes supportive measures and, if severe, thymus or stem cell transplantation.

Overview of DiGeorge Syndrome
VIDEO

DiGeorge syndrome may be

  • Partial: Some T-cell function exists

  • Complete: T-cell function is absent

Symptoms and Signs of DiGeorge Syndrome

Recurrent infections begin soon after birth, but the degree of immunodeficiency varies considerably, and T-cell function may improve spontaneously.

Prognosis often depends on severity of the heart disorder.

Diagnosis of DiGeorge Syndrome

Diagnosis of DiGeorge syndrome is based on clinical findings.

An absolute lymphocyte count is done, followed by B- and T-cell counts and evaluation of lymphocyte subsets if leukopenia is detected. Blood tests to evaluate T-cell and parathyroid function are done. Ig levels and vaccine titers are measured. If complete DiGeorge syndrome is suspected, the T-cell receptor excision circle (TREC) test should also be done.

Parathyroid function is assessed by measuring levels of calcium and parathyroid hormone. Low or even low-normal PTH concentration in patients with hypocalcemia is inappropriate and suggests hypoparathyroidism.

A lateral chest x-ray may help evaluate thymic shadow.

Fluorescent in situ hybridization (FISH) testing can detect the chromosomal deletion in the 22q11 region; standard chromosomal tests to check for other abnormalities may also be done.

If DiGeorge syndrome is suspected or patients have manifestations of congenital heart defects, echocardiography is done. Cardiac catheterization may be necessary if patients present with cyanosis.

Because most cases are sporadic, screening of relatives is not necessary.

Treatment of DiGeorge Syndrome

  • Partial syndrome: Calcium and vitamin D supplementation

  • Complete syndrome: Transplantation of cultured thymus tissue or hematopoietic stem cells

In partial DiGeorge syndrome, hypoparathyroidism is treated with calcium and vitamin D supplementation; long-term survival is not affected.

Treatment reference

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