Advances in the understanding of androgen receptor structure and function and in the development of next-generation AR-targeted therapeutics.

Androgen receptor (AR) and its ligand androgens are important for development and physiology of various tissues. AR and its ligands also play critical role in the development of various diseases, making it a valuable therapeutic target. AR ligands, both agonists and antagonists, are being widely used to treat pathological conditions, including prostate cancer and hypogonadism. Despite AR being studied widely over the last five decades, the last decade has seen striking advances in the knowledge on AR and discoveries that have the potential to translate to the clinic. This review provides an overview of the advances in AR biology, AR molecular mechanisms of action, and next generation molecules that are currently in development. Several of the areas described in the review are just unraveling and the next decade will bring more clarity on these developments that will put AR at the forefront of both basic biology and drug development.

Central neurodegeneration in Kennedy's disease accompanies peripheral motor dysfunction.

Spinal and bulbar muscular atrophy (SBMA), or Kennedy's disease (KD), is a rare hereditary neuromuscular disorder demonstrating commonalities with amyotrophic lateral sclerosis (ALS). The current study aimed to define functional and central nervous system abnormalities associated with SBMA pathology, their interaction, and to identify novel clinical markers for quantifying disease activity. 27 study participants (12 SBMA; 8 ALS; 7 Control) were recruited. SBMA patients underwent comprehensive motor and sensory functional assessments, and neurophysiological testing. All participants underwent whole-brain structural and diffusion MRI. SBMA patients demonstrated marked peripheral motor and sensory abnormalities across clinical assessments. Increased abnormalities on neurological examination were significantly associated with increased disease duration in SBMA patients (R2 = 0.85, p < 0.01). Widespread juxtacortical axonal degeneration of corticospinal white matter tracts were detected in SBMA patients (premotor; motor; somatosensory; p < 0.05), relative to controls. Increased axial diffusivity was significantly correlated with total neuropathy score in SBMA patients across left premotor (R2 = 0.59, p < 0.01), motor (R2 = 0.63, p < 0.01), and somatosensory (R2 = 0.61, p < 0.01) tracts. The present series has identified involvement of motor and sensory brain regions in SBMA, associated with disease duration and increasing severity of peripheral neuropathy. Quantification of annualized brain MRI together with Total Neuropathy Score may represent a novel approach for clinical monitoring.

The various forms of hereditary motor neuron disorders and their historical descriptions.

Motor neuron disorders comprise a clinically and pathologically heterogeneous group of neurologic diseases characterized by progressive degeneration of motor neurons (including both sporadic and hereditary diseases), affecting the upper motor neurons, lower motor neurons, or both. Hereditary motor neuron disorders themselves represent a vast and heterogeneous group, with numerous clinical and genetic overlaps that can be a source of error. This narrative review aims at providing an overview of the main types of inherited motor neuron disorders by recounting the stages in their historical descriptions. For practical purposes, this review of the literature sets out their various clinical characteristics and updates the list of all the genes involved in the various forms of inherited motor neuron disorders, including spinal muscular atrophy, familial amyotrophic lateral sclerosis, hereditary spastic paraplegia, distal hereditary motor neuropathies/neuronopathies, Kennedy's disease, riboflavin transporter deficiencies, VCPopathy and the neurogenic scapuloperoneal syndrome.

271st ENMC international workshop: Towards a unifying effort to fight Kennedy's disease. 20-22 October 2023, Hoofddorp, Netherlands.

The workshop held in the Netherlands from October 20-22, 2023, united 27 scientists from academia, healthcare, and industry representing 11 countries, alongside four patient and charity representatives. Focused on Kennedy's Disease (KD), also known as spinal and bulbar muscular atrophy (SBMA), the workshop aimed to consolidate knowledge, align on clinical trial designs, and promote participative medicine for effective treatments. Discussions emphasized KD's molecular mechanisms, highlighting its status as a neuromuscular disorder with motor neuron degeneration. Strategies for therapeutic intervention, including AR activity modulation and targeting post-translational modifications, were proposed. The need for diagnostic, prognostic, and target engagement biomarkers was stressed. Challenges in patient stratification and clinical trial recruitment were acknowledged, with the International KD/SBMA Registry praised for its role. The workshop concluded with a patient-focused session, underscoring challenges in KD diagnosis and the vital support provided by patient associations.

A systematic review of the association between the age of onset of spinal bulbar muscular atrophy (Kennedy's disease) and the length of CAG repeats in the androgen receptor gene.

Introduction: Spinal bulbar muscular atrophy (SBMA) is an X-linked recessive motor neuron disorder caused by the presence of ≥38 CAG repeats in the androgen receptor gene. Existing literature indicates a relationship between CAG repeat number and the onset age of some motor symptoms of SBMA. This review explores the effect of larger versus shorter CAG repeats on the age of weakness onset in male SBMA patients. Methods: Three databases (October 2021; MEDLINE, SCOPUS, and Web of Science), Cambridge University Press, and Annals of Neurology were searched. 514 articles were initially identified, of which 13 were included for qualitative synthesis. Results: Eleven of the thirteen articles identified a statistically significant inverse correlation between CAG repeat length and age of weakness onset in SBMA. Five studies indicated that SBMA patients with between 35 and 37 CAG repeats had an older age of weakness onset than patients with over 40 CAG repeats. The minimum number of CAG repeats associated with weakness was in the mid-to-late thirties. Conclusion: Identification of a relationship between CAG repeat number and age of weakness may enable earlier detection and intervention for SBMA. In the future, studies should use interviews, chart reviews, and standardized scoring methods to reduce effects of retrospective bias.

Clinical spectrum, biochemical profile and disease progression of Kennedy disease in an Indian cohort.

BACKGROUND: Kennedy disease (KD) is a slowly progressive lower motor neuron degenerative disease. The prevalence of KD is unknown in India. AIM: To describe the phenotypic and laboratory features of an Indian cohort of KD patients. METHODS: A retrospective study was done on seven genetically confirmed KD patients based on demographic, clinical and laboratory details. RESULTS: Mean age at onset and presentation was 37 ± 11.9 and 44.6 ± 13.5 years respectively. Progressive asymmetric proximal and distal limb weakness was the commonest symptom (57.1%). All patients had motor symptoms along with non-specific symptoms such as cramps from the onset. Easy fatigability, decremental response along with ptosis were noted in two patients, which was a novel finding. Gynaecomastia and tongue wasting with fasciculations were universal findings. All five patients with nerve conduction studies showed sensorimotor neuropathy. Magnetic resonance imaging muscle done in two patients showed a prominent moth-eaten appearance in the thigh and posterior leg compartment in one patient. The mean cytosine-adenine-guanine repeats were 44 ± 3.7, and there was no association between age of onset or severity with repeat length. Only one patient required an assistive device for ambulation after 15 years of symptom onset. CONCLUSIONS: This study showed phenotypic heterogeneity in the Indian cohort. The age of onset was earlier with a slowly progressive indolent course as compared with other ethnic cohorts. This highlights the importance of considering the KD diagnosis in patients with the indolent course and suspected ALS diagnosis even with ptosis and fatigability in an appropriate clinical context.

Neurodegeneration in the retina of motoneuron diseases: a longitudinal study in amyotrophic lateral sclerosis and Kennedy's disease.

BACKGROUND: To what extent retinal atrophy in neurodegenerative diseases reflects the severity and/or the chronicity of brain pathology or is a local independent phenomenon remains to be clarified. Moreover, whether retinal atrophy has a clinical (diagnostic and prognostic) value in these diseases remains unclear. OBJECTIVE: To add light on the pathological significance and clinical value of retinal atrophy in patients with amyotrophic lateral sclerosis (ALS) and Kennedy's disease (KD). METHODS: Thirty-five ALS, thirty-seven KD, and forty-nine age-matched healthy controls (HC) were included in a one-year longitudinal study. Spectrum-domain optical coherence tomography (OCT) was performed at study entry (T0) and after 12 months (T1). Disease duration and functional rating scale (FRS) for ALS and KD patients were correlated to retinal thicknesses. RESULTS: Compared to HC, peripapillary retinal nerve fiber layer (pRNFL) thickness was significantly thinner in both ALS (p = 0.034) and KD (p = 0.003). pRNFL was thinner in KD compared to ALS, but the difference was not significant. In KD, pRNFL atrophy significantly correlated with both disease severity (r = 0.296, p = 0.035) and disease duration (r = - 0.308, p = 0.013) while no significant correlation was found in ALS (disease severity: r = 0.147, p = 0.238; disease duration: r = - 0.093, p = 0.459). During the follow-up, pRNFL thickness remained stable in KD while significantly decreased in ALS (p = 0.043). CONCLUSIONS: Our study provides evidence of retinal atrophy in both ALS and KD and suggests that retinal thinning is a primary local phenomenon in motoneuron diseases. The clinical value of pRNFL atrophy in KD is worthy of further investigation.

Acetylation of nuclear receptors in health and disease: an update.

Lysine acetylation is a common reversible post-translational modification of proteins that plays a key role in regulating gene expression. Nuclear receptors (NRs) include ligand-inducible transcription factors and orphan receptors for which the ligand is undetermined, which together regulate the expression of genes involved in development, metabolism, homeostasis, reproduction and human diseases including cancer. Since the original finding that the ERα, AR and HNF4 are acetylated, we now understand that the vast majority of NRs are acetylated and that this modification has profound effects on NR function. Acetylation sites are often conserved and involve both ordered and disordered regions of NRs. The acetylated residues function as part of an intramolecular signalling platform intersecting phosphorylation, methylation and other modifications. Acetylation of NR has been shown to impact recruitment into chromatin, co-repressor and coactivator complex formation, sensitivity and specificity of regulation by ligand and ligand antagonists, DNA binding, subcellular distribution and transcriptional activity. A growing body of evidence in mice indicates a vital role for NR acetylation in metabolism. Additionally, mutations of the NR acetylation site occur in human disease. This review focuses on the role of NR acetylation in coordinating signalling in normal physiology and disease.

Anesthetic and surgical management of tracheotomy in a patient with Kennedy's Disease.

Introduction: Kennedy's disease (KD) is a rare X-linked recessive motor-neuron neuropathy also known as Spinal and Bulbar Muscular Atrophy (SBMA). Case report: We report a case of Kennedy's disease (KD) with acute laryngeal stridor and dysphagia whose anesthesiologic management required a tracheotomy. The surgical procedure was conducted under local anesthesia performed by ultrasound-guided superior laryngeal nerve block and superficial cervical plexus block using 2% lidocaine. The surgical procedure was well tolerated without any discomfort reported from the patient. Conclusions: In KD local anesthesia should be preferred to general anesthesia as general anesthesia is associated with increased potential for laryngospasm, pulmonary aspiration, and respiratory insufficiency related to the use of neuromuscular blocking agents and opioids. At the best of our knowledge, this is the first case of tracheostomy in KD patient under locoregional anesthesia performed thorough superior laryngeal nerve and superficial cervical plexus block.

The role of ubiquitination in spinal and bulbar muscular atrophy.

Spinal and bulbar muscular atrophy (SBMA) is a neurodegenerative and neuromuscular genetic disease caused by the expansion of a polyglutamine-encoding CAG tract in the androgen receptor (AR) gene. The AR is an important transcriptional regulator of the nuclear hormone receptor superfamily; its levels are regulated in many ways including by ubiquitin-dependent degradation. Ubiquitination is a post-translational modification (PTM) which plays a key role in both AR transcriptional activity and its degradation. Moreover, the ubiquitin-proteasome system (UPS) is a fundamental component of cellular functioning and has been implicated in diseases of protein misfolding and aggregation, including polyglutamine (polyQ) repeat expansion diseases such as Huntington's disease and SBMA. In this review, we discuss the details of the UPS system, its functions and regulation, and the role of AR ubiquitination and UPS components in SBMA. We also discuss aspects of the UPS that may be manipulated for therapeutic effect in SBMA.

Proximal Dominant Hereditary Motor and Sensory Neuropathy with TFG Mutation: First Case Report from India.

Hereditary motor and sensory neuropathy with proximal predominance (HMSN-P) is a rare degenerative disorder inherited in an autosomal dominant fashion. This disease was described first in Japanese descendants from Okinawa and Shiga prefectures in mainland Honshu in 1997. The disease is characterized by adult onset of proximal weakness and atrophy, muscle cramps, fasciculations, areflexia, high incidence of elevated creatine kinase, hyperlipidemia, and diabetes mellitus, resembling Kennedy disease, though the mode of inheritance is autosomal dominant, rather than X linked. We examined a 56-year-old male patient with clinical features suggestive of HMSN-P and positive family history in an autosomal dominant fashion. Clinical, electrophysiological, and genetic factors were also reviewed. The appearance of HMSN-P in India and elsewhere calls for clinicians in nonendemic regions to be familiar with this rare disorder, which has typically been geographically confined.

General Anesthesia With Successful Immediate Post-operative Extubation for Sarcoma Excision in a 61-Year-Old Male With Kennedy's Disease.

Kennedy's disease (KD), also known as spinal and bulbar muscular atrophy (SBMA), is a rare, X-linked recessive androgen receptor gene mutation affecting approximately one in 40,000 males. A prominent anesthetic concern in patients with KD is their ability to maintain a patent airway following general anesthesia. We present the case of a 61-year-old man with a history of KD presenting for a left thigh sarcoma excision. The patient received a general anesthetic with endotracheal tube placement, was extubated in the operating room upon completion of the surgery, and had an uneventful post-operative course.

Using genetic testing to diagnose Kennedy's disease: a case report and literature review.

Theoretical basis: Kennedy's disease (KD) is also known as spinal bulbar muscular dystrophy. Because the symptoms of KD are similar to most neuromuscular diseases, it is difficult to make a rapid clinical diagnosis. Patient case: We report the case of a 50-year-old man who was diagnosed with "lumbar disc herniation" five years ago because of progressive proximal limb weakness. After his initial diagnosis, his condition worsened gradually, and a muscle biopsy was performed 3 years ago, and he was then diagnosed with "motor neuron disease", but he had no such family history. His physical examination showed female breast development, erectile dysfunction, a weakness of the quadriceps femoris, a bilateral tendon reflex, and atrophy of the tongue muscle. One year ago, it was found that his blood sugar had increased, and when oral hypoglycemic drugs were given, his blood glucose control was not ideal. At the same time, it was found that his creatine kinase continued to increase significantly. He was admitted to the hospital again because of the aggravation of his walking difficulties. Diagnosis: A laboratory examination showed elevated creatine kinase, an impaired glucose tolerance, and abnormal lactate values. The diagnosis was confirmed using a genetic analysis, which showed a repeated amplification of CAG in the androgen receptor gene. Intervention measures and results: After this diagnosis, the patient had a good prognosis after receiving symptomatic treatment. Lesson: Genetic testing is the key to the diagnosis of KD. Clinicians should make a differential diagnosis, an early diagnosis, and provide treatment as soon as possible according to the patient's clinical manifestations and laboratory examination.

Application Value of the Motor Unit Number Index in Patients With Kennedy Disease.

The aim of this study was to evaluate the usefulness of the motor unit number index (MUNIX) technique in Kennedy disease (KD) and test the correlation between the MUNIX and other clinical parameters. The MUNIX values of the bilateral deltoid, abductor digiti minimi (ADM), quadriceps femoris (QF), and tibialis anterior (TA) were determined and compared with the course of the disease. The MUNIX sum score was calculated by adding the MUNIX values of these 8 muscles. Disability was evaluated using the spinal and bulbar muscular atrophy functional rating scale (SBMAFRS). The MUNIX scores of patients with KD were negatively correlated with the course of the disease (p < 0.05), whereas their motor unit size index (MUSIX) scores were positively correlated with the course the of disease (p < 0.05). MUNIX sum scores were correlated with SBMAFRS scores (r = 0.714, p < 0.05). MUNIX was more sensitive than compound muscle action potentials or muscle strength as an indicator of neuron loss and axonal collateral reinnervation. The MUNIX sum score is an objective and a reliable indicator of disease progression, and it is a potential choice for therapeutic clinical trials. The MUNIX can assess the functional loss of motor axons and is correlated with disability. The MUNIX sum score may be especially suitable as an objective parameter.

Myoglobin: a new biomarker for spinal and bulbar muscular atrophy?

OBJECTIVES: There is a primary muscular affection in spinal and bulbar muscular atrophy (SBMA). Myoglobin (Myo) is mainly distributed in the myocardium and skeletal muscle. The purpose of the study was to explore the significance of serum Myo detection in the diagnosis and clinical evaluation of SBMA. MATERIALS AND METHODS: In this study, serum creatine kinase (CK), Myo, and Troponin T (cTNT) levels were assessed in 80 patients with SBMA and were compared with those of 60 patients with amyotrophic lateral sclerosis (ALS). All measurement data were analyzed using the t-test and enumeration data using the χ2-test. RESULTS: The rate of abnormal Myo levels in the SBMA group was 100%, however, none of the patients with ALS had an abnormal Myo level. There was no overlap between the two groups. The Myo levels in patients with SBMA were correlated with the course of the disease. Further, their CK level was significantly elevated compared with that in patients with ALS, however, there was an overlap between the two groups. The serum cTNT level in patients with SBMA was not significantly different from that in patients with ALS. CONCLUSION: Myo, as a simple, inexpensive, and readily available biochemical indicator, is likely to be used for the differentiation between SBMA and ALS, and used as a new biomarker for the clinical evaluation of SBMA.

Disorders of sleep in spinal and bulbar muscular atrophy (Kennedy's disease).

INTRODUCTION: Spinal and bulbar muscular atrophy (SBMA) is a progressive, X-linked lower motor neuron disorder exclusively affecting men. Since knowledge on sleep disorders in SBMA is scarce compared to other motoneuron diseases, this retrospective case-control study aimed to investigate sleep and sleep-related breathing in patients with SBMA. METHODS: In 23 non-ventilated patients with SBMA (median age 52 years), clinical disease characteristics, forced vital capacity and diagnostic polysomnographies were retrospectively evaluated. In 16 patients, overnight transcutaneous capnometry was available. Twenty-three male control subjects with chronic insomnia were matched for age and body mass index. RESULTS: In patients with SBMA obstructive sleep apnoea (OSA, apnoea-hypopnoea index/AHI > 5/h) was more frequent than in control subjects (14/23 or 61% vs. 6/23 or 26%, p = 0.02), and median AHI was significantly higher in patients (9.0/h vs. 3.4/h, p < 0.01). Among SBMA patients, the AHI was not related to age or body mass index. Alveolar hypoventilation as reflected by nocturnal hypercapnia was found in 3/16 patients. Rapid eye movement (REM) sleep without atonia was present in 44% of SBMA patients but only in 4% of controls (p < 0.01). During REM and non-REM sleep, no behavioural abnormalities were observed in either group. Periodic limb movements in sleep (index > 15/h) were frequent in SBMA patients but rarely disrupted sleep. CONCLUSIONS: In patients with SBMA, sleep-disordered breathing may comprise both OSA and nocturnal hypoventilation. REM sleep without atonia may also be found, but its clinical significance remains unclear. In patients complaining of sleep-related symptoms, cardiorespiratory polysomnography and transcutaneous capnometry are recommended.

[Fatherhood achieved in a case of nonobstructive azoospermia with Kennedy's disease via microdissection testicular sperm extraction and ICSI: A case report and literature review].

OBJECTIVE: To explore the feasibility of biological fatherhood in nonobstructive azoospermia patient with Kennedy's disease and review the relevant literature. METHODS: A twenty-eight man complaining of weakness in the lower extremities for a year underwent physical and laboratory examinations and was found with azoospermia. At the request of the patient for assisted reproduction, we performed microdissection testicular sperm extraction (micro-TESE). RESULTS: Physical examination showed grade-4 and grade-4+ muscular strength in the proximal and distal lower extremities, respectively. The levels of Creatine kinase (CK), serum follicle-stimulating hormone (FSH), luteinizing hormone (LH) and testosterone (T) of the patient were 432 U/L,18.1IU/L,10.4 IU/L and 8.6 nmo/L, respectively. The peroneal motor nerve conduction velocity was significantly decreased. Examination of the androgen receptor (AR) gene revealed 56 CAG repeats in exon 1, which confirmed Kennedy's disease. The patient was found with testicular atrophy and mild gynecomastia but normal seminal plasma biochemical parameters and peripheral karyotype and no Y chromosome microdeletion. Some sperm were found in micro-TESE though none in the previous testicular biopsy. Immunoradiometric assay showed a serum ß-HCG level of 873 IU/L at 2 weeks and ultrasonography manifested clinical pregnancy at 4 weeks after in vitro fertilization-embryo transfer following intracytoplasmic sperm injection (ICSI). At 38 weeks and 2 days of gestation, a healthy boy was born by caesarean in a local hospital. CONCLUSIONS: Nonobstructive azoospermia patients with Kennedy's disease can achieve biological fatherhood via micro-TESE and ICSI.

Kennedy's disease: an under-recognized motor neuron disorder.

Kennedy's disease or spinal bulbar muscular atrophy is a rare, inherited and slowly progressive multisystem disease mostly manifesting with a motor neuron disease phenotype leading to disability. The slow progression, partial androgen insensitivity, electrophysiological evidence of sensory neuronopathy, and relatively spared central nervous system pathways help differentiate it from amyotrophic lateral sclerosis. To date, there is no treatment or cure with clinical care mainly focused on accurate diagnosis, symptom management, patient education, and genetic counselling.