Endocrine Abstracts

JOINT3361

Introduction: Pendred Syndrome is an autosomal recessive syndrome characterized by congenital sensorineural hearing loss and goiter. It is seen as a result of mutation in the SLC26A4 gene, which encodes the chloride/iodine/bicarbonate transporter known as pendrin, which causes organification disorder of iodine in the thyroid gland. The transmembrane protein pendrin is secreted from the inner ear, kidney and bronchial epithelial cells in addition to the thyroid gland. Mutations in the SLC26A4 gene have also been reported in cases of enlarged vestibular aqueduct (EVA) accompanied by deafness.

Case Presentation: An 11.5-year-old girl patient was referred to the pediatric endocrinology clinic due to a thyroid nodule detected incidentally. It was learned that the patient’s 3.5-year-old brother was receiving L-thyroxine treatment due to congenital hypothyroidism, her mother had a total thyroidectomy due to a thyroid nodüle (3 cm size), and her mother’s aunt had a history of multinodular goiter. It was also learned that the patient had a cochlear implant at the age of three due to congenital sensorineural hearing loss, had attention deficit hyperactivity disorder, and wore glasses due to myopia. The patient, who was not related to her parents, had no other known history of hearing loss in her family. In her physical examination, her weight and height are within the normal range for her age, thyroid stage 2 goiter, puberty stage 3. Thyroid function tests were euthyroid, anti thyroglobulin: 1484 IU/mL (0-115) anti TPO: normal thyroglobulin: 76 ng/mL (0.73-84) there was no iodine deficiency. Thyroid ultrasonography reported increased thyroid gland size, slightly heterogeneous parenchyma and several bilateral cystic nodules, the largest of which was 5 mm in size in the lower pole of the right lobe. In light of these findings, the patient underwent a full gene sequence analysis with a preliminary diagnosis of Pendred Syndrome. A homozygous pathogenic variant c.919-2A>G (IVS7-2A>G) located in the splice region of the SLC26A4 gene was detected.

Conclusion: Pendred Syndrome, the most common syndromic form of deafness, is an autosomal recessive disease associated with developmental abnormalities of the cochlea and diffuse goiter (with/without hypothyroidism). The development of goiter and hypothyroidism is closely related to iodine intake. In addition to presentation with solitary thyroid nodule, cases of thyroid carcinoma have also been reported. Treatment is based on clinical findings. Patients with Pendred Syndrome should be followed up by a multidisciplinary team including otolaryngology, endocrinology, genetics and surgery.