Endocrine Abstracts

Introduction: MUTYH (MutY homolog Escherichia coli, homolog of MYH, hMYH) is a repair enzyme with a crucial role in the correction of DNA errors, being considered a protective factor of the cell. MUTYH mutations have been linked to MUTYH-associated polyposis syndrome (MAP), an autosomal recessive disorder characterized by multiple colorectal adenomas. Patients with MAP show a much higher lifetime risk of gastrointestinal cancers as an additional role of MUTYH, it appears to contribute in the involvement of pathologies based on oxidative stress damage, as well as in the prevention of inflammatory and degenerative based disorders. Although the development of extraintestinal pathology is not fully defined, it seems to increase the risk of tumors and endocrinological pathology.

Materials and methods: Prospective study, selecting 27 living patients diagnosed and registered with MUTYH syndrome under follow-up from the Digestive Department of the Hospital Universitario de Navarra (HUN) with current or past follow-up in the Endocrinology Department. Radiological tests, clinical, and analytical variables were analyzed.

Results: The study population included 14 men (51.8%) and 13 women (48.2%), with a mean age of 56 years. The median age at diagnosis of FAP was 48 years, with a mean follow-up time of 8 years. All patients underwent thyroid ultrasound examination and blood tests with the determination of thyroid autoimmunity. None of them had received radiation therapy treatment in childhood or had been exposed to radioactive sources. 48% (13/27) were diagnosed with this disease in the context of endoscopy by digestive clinic, 37% (10/27) by family screening and 4/27 (15%) in the colorectal cancer screening test. The overall prevalence of autoimmunity is 22.2% (4/18). Measured thyroid autoimmunity was peroxidase antibodies. All of them had normal thyroid function, except for two patients who had undergone total thyroidectomy and were on replacement therapy. These two patients had TSH in the normal range before surgery.

Conclusions: The prevalence of thyroid autoimmunity in the sample of patients with MAP is above that described in the general population. Studies with a larger sample size are probably necessary to obtain results with greater statistical significance.