ABSTRACT
BACKGROUND/OBJECTIVES: Spinocerebellar ataxia type 7 (SCA7) is an inherited neurodegenerative disease caused by the expansion of a cytosine-adenine-guanine triplet located in the coding region of the ATXN7 gene, which is characterized by cerebellar ataxia, pigmentary macular degeneration, and dysarthria. Although dysarthria is a common feature in various SCA, its clinical characterization has been barely approached. PATIENTS/METHODS: In this study, we report, to our knowledge for the first time, a detailed voice analysis in a large series of patients with SCA7, using different vocal parameters, including jitter, shimmer, and fundamental frequency. Patients were molecularly diagnosed using fluorescent-based polymerase chain reaction and capillary electrophoresis, and clinically characterized using the Scale for the Assessment and Rating of Ataxia and the Inventory of Non-Ataxia Symptoms. RESULTS: We found altered jitter, shimmer, and fundamental frequency measurements in patients with SCA7 compared with control subjects (P < 0.05). However, voice impairment was found unrelated with both age at disease onset and size of the cytosine-adenine-guanine triplet tract. Remarkably, jitter and shimmer measurements of patients were found to correlate with their Inventory of Non-Ataxia Symptoms, but not with their Scale for the Assessment and Rating of Ataxia scores, implying that voice impairment is the result of extra-cerebellar manifestations of the disease. CONCLUSIONS: We propose that deficiency of the extra-cerebellar component of SCA7 might lead to sudden changes in laryngeal muscle tone, producing instability in sustained vowel phonation. Clinical characterization of voice will help to discriminate SCA7 from other SCA and to guide vocal therapy treatments.
Subject(s)
Ataxin-7/genetics , Laryngeal Muscles/innervation , Mutation , Phonation , Speech Acoustics , Spinocerebellar Ataxias/complications , Voice Disorders/etiology , Voice Quality , Acoustics , Adult , Aged , Case-Control Studies , DNA Mutational Analysis , Female , Genetic Predisposition to Disease , Humans , Male , Mexico , Middle Aged , Phenotype , Speech Production Measurement , Spinocerebellar Ataxias/diagnosis , Spinocerebellar Ataxias/genetics , Voice Disorders/diagnosis , Voice Disorders/physiopathologyABSTRACT
BACKGROUND: Resistance to thyroid hormone (RTH) is a rare condition characterized by elevation of thyroid stimulating hormone (TSH) and thyroid hormones (TH). Its association with Hashimoto's thyroiditis was described in 1993 and occurs in 1 of 1.3 million births. CLINICAL CASE: We present a female patient with a family history of hypothyroidism. The patient's condition began in 2008 with symptoms of hyperthyroidism, elevated triiodothyronine (T3), thyroxine (T4) and TSH levels. Thyroid scan showed hypermetabolic activity and she was positive for anti-peroxidase antibodies (anti-TPO). After administration of thiamazole, TSH increased. In 2009 she was diagnosed with clinical hypothyroidism, high levels of TSH, and normal T3 and T4 levels. Levothyroxine was prescribed but TSH increased and she presented clinical signs of hyperthyroidism. Patient abandoned treatment after 1 month. Her symptoms fluctuated among hyperthyroidism, euthyroidism and hypothyroidism. In 2010 she presented tachycardia, weight loss, and high T3, T4 and TSH levels. Thyrotropin-secreting adenoma (TSHoma) was suspected and ruled out by magnetic resonance imaging (MRI). Thyrotropin releasing hormone (TRH) test was performed. TSH increased and the α-subunit of pituitary hormones retained low levels. CONCLUSIONS: RTH diagnosis requires exclusion of a TSHoma because both present a similar pattern according to thyroid tests. The association between Hashimoto's thyroiditis and RTH is not well known. This pathological condition has a mutated TRß gene in 75% of the cases.