Characteristics of spinal and bulbar muscular atrophy in South Korea: a cross-sectional study of 157 patients

Abstract

Spinal and bulbar muscular atrophy, namely Kennedy disease, is a rare progressive neurodegenerative disorder caused by the expansion of a CAG repeat in the first exon of the androgen receptor gene on the X chromosome. We assessed the clinical history, laboratory findings, functional scales, and electrophysiological data, as well as the levels of luteinizing hormone, follicle-stimulating hormone and testosterone, in 157 Korean patients with genetically confirmed spinal and bulbar muscular atrophy (mean age at data collection = 56.9 years; range = 33–83 years). Hand tremor was the first symptom noticed by patients at a median age of 35 years, followed by gynecomastia, orofacial fasciculation, cramps, and fatigability in ascending order. Clinical symptoms such as paresthesia and dysphagia appeared during the later stages of the disease. Cane use during ambulation began at a median age of 62 years. There were statistically significant differences between patients and controls in the results of sensory nerve studies, motor conduction velocity, and distal latencies. Furthermore, among the hormone markers analyzed, the level of luteinizing hormone exhibited a negative correlation with the spinal and bulbar muscular atrophy functional rating scale, Korean version. However, among the patients with a disease duration of ≤5 years, the levels of luteinizing hormone showed a significant correlation with assessments using the amyotrophic lateral sclerosis functional rating scale-revised, spinal and bulbar muscular atrophy functional rating scale, Korean version and the 6-minute walk test. In conclusion, our findings provide clinical information from a substantial number of patients with spinal and bulbar muscular atrophy in Korea that accorded with that of patients with this disease worldwide but with updated clinical features.

Whole‐Body Muscle Magnetic Resonance Imaging in 81 Patients with Spinal and Bulbar Muscular Atrophy: A Prospective Study

“…27 Additionally, serum creatinine levels begin to decline in patients with SBMA >10 years before the onset of muscle weakness and continue to decline with clinical progression. 4,10,28 In this study, whole-body muscle MRI confirmed that serum creatinine levels decreased with the progression of fat infiltration, consistent with previous studies' findings. Serum creatinine appears to be a promising biomarker for assessing muscle mass in patients with SBMA.…”

“…[34][35][36] FSH and LH levels tend to be elevated from their normal values. 30 Furthermore, LH levels demonstrate negative correlation with clinical scales, 4 whereas testosterone levels demonstrate positive correlation with the clinical scales. 4,11 In this study, the FSH levels increased as the fat infiltration progressed (see Fig 3); however, the levels of LH and testosterone remained relatively constant (Fig S2).…”

“…Prior studies have indicated an inverse relationship between the number of CAG repeats and the age at onset and age at evaluation. 2,4,6,8 Moreover, the number of CAG repeats has been associated with electrophysiological motor and sensory phenotypes. 25,26 In previous studies, the number of CAG repeats did not correlate with functional scales or the progression rate of muscle fat content.…”

“…Mobility with the assistance of a cane typically begins around the age of 60 years. 2,[4][5][6][7][8][9] These symptoms are accompanied by increased muscle fat content, decreased muscle strength, and reduced walking ability. 10 Additionally, blood levels of creatinine and hormones, such as testosterone, have shown correlations with muscle fat, strength, and functions.…”

“…10 Additionally, blood levels of creatinine and hormones, such as testosterone, have shown correlations with muscle fat, strength, and functions. 4,11 Previous studies have reported the pattern of fat infiltration in the muscles of patients with SBMA. 12 Recent research utilizing whole-body muscle magnetic resonance imaging (MRI) has shown diffuse muscle involvement, with a predominance of leg muscles over arm muscles and posterior flexor muscles over extensor muscles.…”