Mindy S Lo1, Meghan Towne2, Grace E VanNoy2, Catherine A Brownstein2, Andrew A Lane3, Talal A Chatila4, Pankaj B Agrawal5. 1. Divisions of Immunology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, United States. Electronic address: mindy.lo@childrens.harvard.edu. 2. Genetics and Genomics, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, United States; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA, United States. 3. Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, United States. 4. Divisions of Immunology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, United States. 5. Genetics and Genomics, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, United States; Division of Newborn Medicine, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, United States; The Manton Center for Orphan Disease Research, Boston Children's Hospital and Harvard Medical School, Boston, MA, United States.
Abstract
BACKGROUND: Risk of autoimmune thyroid disease (AITD) is strongly heritable. Multiple genes confer increased risk for AITD, but a monogenic origin has not yet been described. We studied a family with apparent autosomal dominant, early onset Hashimoto thyroiditis. METHODS: The family was enrolled in an IRB-approved protocol. Whole exome sequencing was used to study the proband and an affected sibling. The identified variant was studied in other family members by Sanger sequencing. RESULTS: We identified a previously unreported splice site variant in the thyroglobulin gene (TG c.1076-1G > C). This variant was confirmed in all affected family members who underwent testing, and also noted in one unaffected child. The variant is associated with exon 9 skipping, resulting in a novel in-frame variant transcript of TG. CONCLUSION: We discovered a monogenic form of AITD associated with a splice site variant in the thyroglobulin gene. This finding raises questions about the origins of thyroid autoimmunity; possible explanations include increased immunogenicity of the mutated protein or thyroid toxicity with secondary development of anti-thyroid antibodies. Further study into the effects of this variant on thyroid function and thyroid autoimmunity are warranted.
BACKGROUND: Risk of autoimmune thyroid disease (AITD) is strongly heritable. Multiple genes confer increased risk for AITD, but a monogenic origin has not yet been described. We studied a family with apparent autosomal dominant, early onset Hashimoto thyroiditis. METHODS: The family was enrolled in an IRB-approved protocol. Whole exome sequencing was used to study the proband and an affected sibling. The identified variant was studied in other family members by Sanger sequencing. RESULTS: We identified a previously unreported splice site variant in the thyroglobulin gene (TG c.1076-1G > C). This variant was confirmed in all affected family members who underwent testing, and also noted in one unaffected child. The variant is associated with exon 9 skipping, resulting in a novel in-frame variant transcript of TG. CONCLUSION: We discovered a monogenic form of AITD associated with a splice site variant in the thyroglobulin gene. This finding raises questions about the origins of thyroid autoimmunity; possible explanations include increased immunogenicity of the mutated protein or thyroid toxicity with secondary development of anti-thyroid antibodies. Further study into the effects of this variant on thyroid function and thyroid autoimmunity are warranted.