SUMMARY
1. Turner syndrome is caused by partial or complete loss of an X chromosome (45, X). Patients are characterized by the following clinical features:
-Short stature
-Shield chest
-Congenital lymphedema
-Ovarian dysgenesis
-Renal anomalies
-Cardiovascular disease
2. Patients also have an increased risk for sinopulmonary infections and autoimmunity. Immunologic abnormalities reported in patients include decreased immunoglobulin levels, decreased T cell number, and decreased T cell function. Turner syndrome patients with CVID have been reported.
3. The diagnosis of Turner syndrome can be established by standard karyotyping.
4. For patients with hypogammaglobulinemia and recurrent infections, management options include prophylactic antibiotics and immunoglobulin replacement therapy.
OVERVIEW
Turner syndrome is caused by partial or complete loss of an X chromosome (45, X). Patients are characterized by the following clinical features:
-Short stature
-Shield chest
-Congenital lymphedema
-Ovarian dysgenesis
-Renal anomalies
-Cardiovascular disease
Patients also have an increased risk for sinopulmonary infections and autoimmunity. Immunologic abnormalities reported in patients include decreased immunoglobulin levels, decreased specific antibody responses, decreased T cell number, and decreased T cell function. The exact mechanism by which patients develop immunodeficiency is unknown.
EVALUATION
Step 1: Evaluation for Turner syndrome
-Karyotype
-Standard karyotyping will reveal a 45, X pattern instead of 46, XX.
Step 2: Immune Evaluation
-IgG, IgM, IgA
-Specific antibody responses to vaccine antigens (if older than 6 months)
-Lymphocyte subset enumeration by flow cytometry (CD3, CD4, CD8, CD19, CD16/56)
-In vitro T cell proliferation to mitogens (PHA, ConA, PWM)
-Low immunoglobulin levels have been reported in patients.
-Specific antibody responses may be decreased. Both protein (tetanus, diphtheria) and polysaccharide (pneumococcus) antigen responses should be measured.
-T cell numbers may be decreased in patients.
-Decreased T cell proliferation in response to mitogens has been reported.
MANAGEMENT
Patients with a CVID phenotype (low IgG and impaired specific antibody responses) are candidates for immunoglobulin replacement therapy. Typical replacement is started with 400-600mg/kg of IVIG every 4 weeks. Trough IgG levels should be checked after 5 IVIG doses. It is clear that patients who maintain trough IgG levels above 700-900mg/dl have fewer infectious complications.
RESOURCES
Literature Resources
1. Al-Attas 1997
Turner syndrome and CVID (case report)