SUMMARY
1. Acrodermatitis Enterohepathica (AE) is an autosomal recessive disorder characterized by impaired zinc absorption.
2. Patients present during infancy with severe dermatitis, alopecia, diarrhea, zinc deficiency, and recurrent infections. Infants who are breasfed may have delayed onset of symptoms (after weaning).
3. A markedly decreased plasma zinc level (<50 ug/dl) is characteristic of AE.
4. The deficiency of zinc has a number of effects on the immune system including decreased humoral and cellular immunity.
5. AE is caused by mutations in the SLC39A4 gene, which encodes a protein that appears to be involved in zinc transportation.
6. Oral zinc supplementation (3mg/kg/day of elemental zinc) results in clinical remission and normalization of immune abnormalities.
OVERVIEW
Acrodermatitis Enterohepathica (AE) is an autosomal disorder characterized by impaired zinc absorption. Patients present during infancy with severe dermatitis, alopecia, diarrhea, zinc deficiency, and recurrent infections. Infants who are breasfed may have delayed onset of symptoms (after weaning). The deficiency of zinc has a number of effects on the immune system including decreased humoral and cellular immunity. AE is caused by mutations in the SLC39A4 gene, which encodes a protein that appears to be involved in zinc transportation.
EVALUATION
A diagnosis of AE is suggested by the presence of classic clinical features (dermatitis, diarrhea, alopecia) and markedly decreased plasma zinc levels (<50 ug/dl).
Step 1: Immune Evaluation
Both humoral and cell-mediated immune abnormalities have been reported in patients with AE.
IgG, IgM, IgASpecific antibody responses to vaccine antigens
Lymphocyte subset enumeration by flow cytometry (CD3, CD4, CD8, CD19, CD16/56)
In vitro T cell proliferation to mitogens (PHA, ConA, PWM)
Step 2: Gene Sequencing
SLC39A4 gene sequencing
The presence of homozygous SLC39A4 mutations can confirm the diagnosis.
MANAGEMENT
Lifelong oral zinc supplementation (3mg/kg/day of elemental zinc) results in clinical remission and normalization of immune abnormalities. Without treatment, malnutrition and death may occur by the age of 3 years.