Presenter Status

Fellow

Abstract Type

Case report

Primary Mentor

Nikita Raje, MD

Start Date

5-5-2022 11:30 AM

End Date

5-5-2022 1:30 PM

Presentation Type

Poster Presentation

Description

Introduction: Hereditary Alpha Tryptasemia (HαT) is an autosomal dominant disorder characterized by an elevated baseline tryptase that occurs up to 3% of the population and clinically resembles mast cell activation syndrome.

Case description: A full-term, 13-month-old female patient presented to Allergy and Immunology clinic for persistently elevated tryptase. Her initial symptom was non-bloody loose stools, but she later developed recurrent flushing, joint pain, constipation, and frequent nighttime awakenings. Her past medical history included gastroesophageal reflux disease. Family history was significant for an older sibling with history of flushing. At all visits, physical examination was normal. Tryptase ranged between 11.7 - 13.0 ng/ml and initial eosinophilia and thrombocytosis resolved on repeat testing. C-kit mutation was negative in peripheral blood. She was referred to Gastroenterology, Dermatology, Hematology/Oncology, and Rheumatology. Esophagogastroduodenoscopy showed only mild reflux. Skin findings were not consistent with urticarial vasculitis or cutaneous mastocytosis. Bone marrow biopsy was not indicated due to normalization of her platelets, no enlarged spleen, and rare incidence of mastocytosis. Autoimmune diseases were deemed unlikely. Microarray was obtained and showed an extra allelic alpha-tryptase copy at TPSAB1. Given her symptoms, genetic testing, and elevated baseline tryptase, she was diagnosed with Hereditary Alpha Tryptasemia. Her symptoms improved on low dose cromolyn and cetirizine.

Discussion: Hereditary Alpha Tryptasemia is characterized by elevated baseline tryptase of 8 ng/ml or greater and an increased copy number of alpha tryptase allele at TPSAB1 seen on genetic testing. Treatment is supportive in nature.

Educational Objective: After reviewing this case, participants should be able to include Hereditary Alpha Tryptasemia (HαT) in their differential when evaluating a patient with an elevated tryptase.

MeSH Keywords

tryptase; hereditary alpha tryptasemia

Additional Files

A case of an elevated tryptase.pdf (105 kB)
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May 5th, 11:30 AM May 5th, 1:30 PM

A case of an elevated tryptase

Introduction: Hereditary Alpha Tryptasemia (HαT) is an autosomal dominant disorder characterized by an elevated baseline tryptase that occurs up to 3% of the population and clinically resembles mast cell activation syndrome.

Case description: A full-term, 13-month-old female patient presented to Allergy and Immunology clinic for persistently elevated tryptase. Her initial symptom was non-bloody loose stools, but she later developed recurrent flushing, joint pain, constipation, and frequent nighttime awakenings. Her past medical history included gastroesophageal reflux disease. Family history was significant for an older sibling with history of flushing. At all visits, physical examination was normal. Tryptase ranged between 11.7 - 13.0 ng/ml and initial eosinophilia and thrombocytosis resolved on repeat testing. C-kit mutation was negative in peripheral blood. She was referred to Gastroenterology, Dermatology, Hematology/Oncology, and Rheumatology. Esophagogastroduodenoscopy showed only mild reflux. Skin findings were not consistent with urticarial vasculitis or cutaneous mastocytosis. Bone marrow biopsy was not indicated due to normalization of her platelets, no enlarged spleen, and rare incidence of mastocytosis. Autoimmune diseases were deemed unlikely. Microarray was obtained and showed an extra allelic alpha-tryptase copy at TPSAB1. Given her symptoms, genetic testing, and elevated baseline tryptase, she was diagnosed with Hereditary Alpha Tryptasemia. Her symptoms improved on low dose cromolyn and cetirizine.

Discussion: Hereditary Alpha Tryptasemia is characterized by elevated baseline tryptase of 8 ng/ml or greater and an increased copy number of alpha tryptase allele at TPSAB1 seen on genetic testing. Treatment is supportive in nature.

Educational Objective: After reviewing this case, participants should be able to include Hereditary Alpha Tryptasemia (HαT) in their differential when evaluating a patient with an elevated tryptase.