Question: Which hormone abnormalities are characteristic to Pendred syndrome?

Context:
Loss or reduction of function mutations of SLC26A4 underlie Pendred syndrome, a disorder invariably leading to hearing loss with enlarged vestibular aqueducts and in some patients to hypothyroidism and goiter.
Goiter development and hypothyroidism vary among affected individuals and seem to be partially dependent on nutritional iodide intake.
Elucidation of the molecular basis of Pendred syndrome and the function of pendrin has provided unexpected novel insights into the pathophysiology of the inner ear, thyroid hormone synthesis, and chloride/bicarbonate exchange in the kidney.
Thyroid goiter was found in 46.5% of cases.
Biallelic mutations of SLC26A4 (encoding pendrin) cause Pendred syndrome (PS), an autosomal recessive genetic disorder with deafness and goiter.
From age 15 years, her thyroid gland showed progressive enlargement accompanied by elevation of serum thyroglobulin reaching 10-fold the normal amount. 
In summary, a molecularly confirmed PS patient showed goiter progression accompanied by elevated serum thyroglobulin and increased thyroidal iodine uptake, but normal serum TSH levels and normal iodine organification.
A coherent organization of differentiation proteins is required to maintain an appropriate thyroid function in the Pendred thyroid.
Pendred syndrome is an autosomal recessive disorder defined by sensorineural deafness, goiter and a partial organification defect of iodide. 
The clinical phenotype of patients with Pendred syndrome and the fact that pendrin can mediate iodide efflux in transfected cells suggest that this anion exchanger may be involved in mediating iodide efflux into the follicular lumen, a key step in thyroid hormone biosynthesis. 
Results of immunoblot and immunofluorescence experiments reveal that TSH and forskolin rapidly increase pendrin abundance at the plasma membrane through the protein kinase A pathway in PCCL-3 rat thyroid cells. 
These results demonstrate that pendrin translocates to the membrane in response to TSH and suggest that it may have a physiological role in apical iodide transport and thyroid hormone synthesis.
Mutations in the SLC26A4 gene, coding for the anion transporter pendrin, are responsible for Pendred syndrome, characterized by congenital sensorineural deafness and dyshormonogenic goiter. 
Pendred syndrome is an autosomal recessive disorder characterized by sensorineural deafness, goiter and a partial defect in iodide organification. Goiter development and hypothyroidism vary and appear to depend on nutritional iodide intake. 
Pendrin is mainly expressed in the thyroid, the inner ear, and the kidney. In the thyroid, pendrin localizes to the apical membrane of thyrocytes, where it may be involved in mediating iodide efflux. 
Mutations of SLC26A4 cause an enlarged vestibular aqueduct, nonsyndromic deafness, and deafness as part of Pendred syndrome. SLC26A4 encodes pendrin, an anion exchanger located in the cochlea, thyroid, and kidney. 
Genetic causes of goiter and deafness: Pendred syndrome in a girl and cooccurrence of Pendred syndrome and resistance to thyroid hormone in her sister.
Goiter and deafness can be associated in some genetic syndromes, e.g. Pendred syndrome (PS) and resistance to thyroid hormone (RTH). PS is an autosomal recessive disorder characterized by goiter and sensorineural hearing impairment with an enlarged vestibular aqueduct bilaterally.
The elder sister had an elevated TSH level at newborn screening followed by subclinical hypothyroidism, childhood-onset goiter, and bilateral progressive sensorineural hearing impairment with enlarged vestibular aqueducts, consistent with a diagnosis of PS.
This is the first report of the cooccurrence, in the same individual, of PS and RTH, two genetic syndromes both associated with goiter and hearing impairment.
Its diagnosis requires identification of the classical triad of symptoms, including hypoacusis, thyroid goitre and iodine organification defect in the thyroid, which may lead to thyroid functional disorders of hypothyroidism.
Endocrine examination showed hypothyroidism in 5, its subclinical form in 1, diffuse thyroid goitre in 4 and nodular thyroid goiter in 2 cases.
Biallelic mutations in the SLC26A4 gene lead to Pendred syndrome, an autosomal recessive disorder characterized by sensorineural deafness, goiter, and impaired iodide organification. 
Thyroidectomy in a patient with multinodular dyshormonogenetic goitre--a case of Pendred syndrome confirmed by mutations in the PDS/SLC26A4 gene.
We report a young woman with genetically confirmed Pendred syndrome and discuss the current therapeutic strategies of dyshormonogenetic goitre.
Management of a patient with Pendred syndrome requires careful follow-up and regular imaging of the thyroid. 
Pendred syndrome is an autosomal recessive disorder characterized by sensorineural hearing impairment, presence of goiter, and a partial defect in iodide organification, which may be associated with insufficient thyroid hormone synthesis. Goiter development and development of hypothyroidism are variable and depend on nutritional iodide intake.
Pendred syndrome (PS) is an autosomal recessive disease that is characterized by congenital sensorineural hearing loss, goiter, and a partial iodine organification defect. 
Levels of thyroid hormones were essentially normal in all patients: 2 patients had goiters and/or elevated serum thyroglobulin levels, whereas 2 other patients had positive thyroid antibodies and a positive perchlorate discharge test. 
Pendred syndrome, defined as the constellation of goiter, sensori-neural hearing loss, and positive perchlorate discharge test, is the most frequent cause of congenital deafness. 
Presuming the classic triad as the gold standard, we compared MRI findings in six such defined patients with six cases having goiter, hearing loss, and normal perchlorate discharge test. 
For over 100 years after the first description of the disorder, the molecular pathology underlying the deafness and thyroid pathology in Pendred syndrome (PS) remained unknown. 
We review the literature to identify genetic defects involved in the iodination process of the thyroid hormone synthesis, particularly defects in iodide transport from circulation into the thyroid cell, defects in iodide transport from the thyroid cell to the follicular lumen (Pendred syndrome), and defects of iodide organification.
Among those causing dyshormonogenesis, the thyroid peroxidase and thyroglobulin genes were initially described, and more recently PDS (Pendred syndrome), NIS (sodium iodide symporter), and THOX2 (thyroid oxidase 2) gene defects. 
Among permanent CH cases, those with a goitre (n = 27) had an iodine organification defect (n = 10), Pendred syndrome (n = 1), a defect of thyroglobulin synthesis (n = 8), or a defect of sodium iodine symporter (n = 1), and in seven patients no aetiology could be determined.
Pendred syndrome consists in sensorineural deafness, goiter and impaired thyroid hormone synthesis while in EVA thyroid function seems to be preserved.
All patients harbouring mutations in the SLC26A4 gene had goiter and a positive perchlorate discharge test: 3 were slightly hypothyroid and 2 euthyroid. 
Patients with mutations in the SLC26A4 gene had larger thyroid volume (p<0.002), higher serum thyroglobulin (Tg) levels (p<0.002) and greater radioiodine discharge after perchlorate (p=0.09) than patients without mutations. 
The autosomal recessive Pendred's syndrome is defined by congenital sensorineural deafness, goiter, and impaired iodide organification. 
Two patients were hypothyroid, two individuals were euthyroid.
Pendred syndrome is an autosomal recessive disorder characterized by congenital deafness and thyroid goiter. 
Pendred syndrome is an autosomal recessive disorder characterized by the association between sensorineural hearing loss and thyroid swelling or goitre and is likely to be the most common form of syndromic deafness. 
Pendred syndrome is a recessive inherited disorder that consists of developmental abnormalities of the cochlea, sensorineural hearing loss, and diffuse thyroid enlargement (goiter).
Pendred syndrome consists in sensorineural deafness, goiter and impaired thyroid hormone synthesis while in EVA thyroid function seems to be preserved
Biallelic mutations of SLC26A4 (encoding pendrin) cause Pendred syndrome (PS), an autosomal recessive genetic disorder with deafness and goiter
Pendred syndrome (PS) is an autosomal recessive disease that is characterized by congenital sensorineural hearing loss, goiter, and a partial iodine organification defect
Individuals were assigned affected status based on the characteristic clinical features of Pendred's syndrome, namely the presence of congenital sensorineural hearing loss and the appearance in early life of a goitre

Answer: Thyroid hormone abnormalities are characteristic to Pendred syndrome. Hypothyroidism is the most common thyroid hormone abnormality in Pendred syndrome. Pendred syndrome  is an autosomal recessive disorder characterized by sensorineural deafness, goiter and a partial defect in iodide organification.
Exact answer: thyroid hormone abnormalities