TEST CATALOG ORDERING & RESULTS SPECIMEN HANDLING CUSTOMER SERVICE EDUCATION & INSIGHTS
Test Catalog

Test ID: LRBA    
Lipopolysaccharide-Responsive Beige-Like Anchor Protein (LRBA) Deficiency, Blood

Useful For Suggests clinical disorders or settings where the test may be helpful

Aids in the diagnosis of lipopolysaccharide-responsive beige-like anchor protein (LRBA) deficiency

 

This test is not useful for identifying a carrier status for LRBA deficiency.

Genetics Test Information Provides information that may help with selection of the correct genetic test or proper submission of the test request

The human lipopolysaccharide-responsive beige-like anchor protein (LRBA) gene is on chromosome 4.

 

Assessment of 109 patients with LRBA deficiency has shown 93 homozygous and 16 compound heterozygous alterations in the gene.

 

Alterations in the LRBA gene have been observed throughout the length of the gene and include the following main categories: Nonsense; missense; insertions, deletions, indels, and splice site alterations.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Lipopolysaccharide-responsive beige-like anchor protein (LRBA) deficiency is a rare autosomal recessive primary immunodeficiency disease (PID) caused by homozygous or compound heterozygous loss-of-function variants in the LRBA gene. It has a wide spectrum of clinical manifestations, including immune dysregulation and autoimmunity, inflammatory bowel disease (IBD), early-onset hypogammaglobulinemia, recurrent infections and organomegaly.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

The appropriate reference values will be provided on the report.

Interpretation Provides information to assist in interpretation of the test results

The results are reported as the percentage and MFI (mean fluorescence intensity) of lipopolysaccharide-responsive beige-like anchor protein (LRBA) expression in T cells and B cells.

 

The majority of genetically confirmed cases of LRBA deficiency lead to the absence of LRBA expression. Therefore, the lack of LRBA expression in T and B cells is consistent with LRBA deficiency. In this case, genetic analysis of LRBA to confirm the diagnosis and to identify the underlying variant will be recommended.

 

In addition, there are reported cases of LRBA deficiency where the protein is expressed but at lower intensity. Therefore, the expression of LRBA at diminished intensity could be due to a pathogenic LRBA variant, which would have to be confirmed or ruled out by genetic and functional analysis.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

No significant cautionary statements

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Lopez-Herrera G, Tampella G, Pan-Hammarstrom Q, et al: Deleterious mutations in LRBA are associated with a syndrome of immune deficiency and autoimmunity. Am J Hum Genet. 2012;90:986-1001

2. Gamez-Diaz L, August D, Stepensky P, et al: The extended phenotype of LPS-responsive beige-like anchor protein (LRBA) deficiency. J Allergy Clin Immunol. 2016;137:223-230

3. Habibi S, Zaki-Dizaji M, Rafiemanesh H, et al: Clinical, immunologic, and molecular spectrum of patients with LPS-responsive beige-like anchor protein deficiency: A systematic review. J Allergy Clin Immunol Pract. 2019;7:2379-86 e5

4. Serwas NK, Kansu A, Santos-Valente E, et al: Atypical manifestation of LRBA deficiency with predominant IBD-like phenotype. Inflamm Bowel Dis. 2015;21:40-47

5. Revel-Vilk S, Fischer U, Keller B, et al: Autoimmune lymphoproliferative syndrome-like disease in patients with LRBA mutation. Clin Immunol. 2015;159:84-92

6. Kiykim A, Ogulur I, Dursun E, et al: Abatacept as a long-term targeted therapy for LRBA deficiency. J Allergy Clin Immunol Pract. 2019;7:2790-800 e15

7. Tesch VK, Abolhassani H, Shadur B, et al: Long-term outcome of LRBA deficiency in 76 patients after various treatment modalities as evaluated by the immune deficiency and dysregulation activity (IDDA) score. J Allergy Clin Immunol. 2020;145:1452-1463