PEDBASE.org - The Pediatric Database - Detailed information of DIGEORGE ANOMALY

DIGEORGE ANOMALY

DEFINITION:

A disorder characterized by injury to a developmental field affecting the development of pharyngeal pouches resulting in cardiac, facial, immune, and parathyroid anomalies.

EPIDEMIOLOGY:

incidence: ?
age of onset:
- newborn (neonatal hypocalcemia)
risk factors:
- familial - autosomal recessive
  - chrom.#: 22q11
  - gene: ?
- M = F

PATHOGENESIS:

1. Background

"developmental fields are embryologically reactive units consisting of cells that develop with their primordia" (Nelsons)
an injury to a developmental field by any of a multitude of factors may result in a limited range of abnormal phenotypes

2. Genetic Defect

injury to the cephalic neural crest cells by any cause (fetal alcohol syndrome, chromosomal abnormalities) in a genetically predisposed individual -> interrupts the development and differentiation of the pharyngeal pouches resulting in cardiac, facial, immune, and parathyroid anomalies
immune deficit
- probably due to a thymic abnormality and is variable in severity
- most patients have a minimal defect with normal immunity
- when the deficit includes T-helper cell function, immunoglobulin synthesis is absent

CLINICAL FEATURES:

1. Cardiac Manifestations

1. Conotruncal Defects

interrupted aortic arch type B defect
right-sided aortic arch
persistent truncus arteriosus
aberrant left subclavian artery
right infundibular stenosis
VSD

2. Facial Manifestations

hypertelorism
down-slanting eyes
low-set posterior angulated auricles
high-arched palate
bifid uvula
fishmouth deformity
micrognathia

3. Endocrine Manifestations

frequently the initial clinical presentation
hypoparathyroidism
- neonatal hypocalcemia +/- tetany and cataracts

4. Immune Manifestations

most patients have or will acquire normal immunity
if T cell function is compromised - increased incidence of fungal or viral infections

INVESTIGATIONS:

1. Serum

CBC - normal lymphocytes
decreased immunoglobulins (IgA and IgG) if abnormal T helper cell function
elevated IgE
decreased hypothyroid hormone with hypocalcemia
normal thyroid function tests