Study On Clinical Manifestations,Electrophysiological Findings And Genetic Features Of Kennedy Disease

BackgroundKennedy Disease(KD),also known as Spinal and Bulbar Muscular Atrophy(SBMA),Modern medical studies have found that Kennedy disease is a X linked recessive disease,caused by the amplification of repeated sequences CAG exon 1 of the androgen receptor gene in the Xq11-12 position.The progress course of this disease is slow and it mainly shows the symptoms of tired and weak limbs and medullary muscle,gynecomastia,sterilitas virilis and low sexual desire.In the United States,there is about 1 / 4 0,0 0 0incidence of Kennedy Disease.A higher incidence of Kennedy Disease could be seen in Europe,especially Italy and Finland.There are no reliable epidemiological statistics because of insufficient understanding and relatively rare discovery of Kennedy disease in China in the past.In recent years,with the continuous development of relevant testing means and the gradual popularization of gene diagnosis technology,Kennedy disease in China has gained more understanding of the disease diagnosis and treatment.There exists difference in clinical symptoms and laboratory testing of Kennedy disease in different regions.ObjectiveTo study the relationship between the clinical features,electrophysiological features and genes of Kennedy disease patients in Henan province can provide basis for disease diagnosis and differential diagnosis.MethodsThis study will include 14 patients of Henan Province confirmed as Kennedy disease in our hospital from January 2017 to August 2020.The control subjects will be selected with 25 volunteers who were similar in age to the case subjects and had negative results in neuro electrophysiological examination.Correlation analysis will be conducted between clinical manifestation,laboratory examination,electrophysiological findings and hereditary features based on the experimental records of Kennedy disease patients.The collected data are in accordance with the normal distribution;the pairwise comparative measurement data are analyzed by T test;the analysis of correlation is Pearson correlated.When the results show P<0.05,it means the difference is statistically significant.All the data collected in this experiment were analyzed by SPSS21.0 software.Results1.Both case and control subjects were male.With the average age of the case subjects(51.28±12.34),and control subjects(49.72±10.24),there is no statistical significance(P>0.05);The average onset age in the case subjects(46.43±10.99),course of disease(4.78±3.11),CAG repeats 39-54 and affected areas(3.0±1.0).2.There were 12(86%)people with limbs as the initial pathogenic site,of which 8(57%)with the lower limbs as the initial pathogenic site,4(29%)with the upper limbs as the initial pathogenic site,and 2(14%)with bulbar symptoms as the initial pathogenic site.The incidence of different clinical manifestations is different,11(78%)had tongue muscle atrophy,5(38%)had bulbar symptoms such as choking drinking and slurred speech,9(64%)men had gynecomastia and 3(21%)had abnormal limbs.3.Motor nerve conduction in case subjects and control subjects:The amplitude difference between ulnar nerve and peroneal nerve was statistically significant(ulnar nerve: P=0.014;peroneal nerve: P=0.001);Motor nerve amplitude difference of median nerve and posterior tibial nerve was not statistically significant(P>0.05);The distal latency difference between median,ulnar,posterior and peroneal nerves was not statistically significant(P>0.05);Motor conduction velocity difference between median,ulnar,posterior and peroneal nerves was not statistically significant(P>0.05);4.Sensory nerve conduction in case subjects and control subjects:Action potential amplitude difference of sensory nerve between median nerve,ulnar nerve,sural nerve was statistically significant(Median: P=0.000;ulnar: P=0.000;gastrocnemius: P=0.001)Sensory conduction velocity in sural nerve was statistically significant(P=0.038)Sensory conduction velocity in median and ulnar nerves was not statistically significant(P>0.05)5.The results of the needle electromyography of Kennedy patients showed as follows:the proportion of active damage(abnormal examined muscles/total examined muscles):cranial segment 22%,cervical segment 45%,chest segment 36%,lumbosacral segment40%.It can be seen that the active damage of the examined muscles in the cervical segment is the most obvious;the proportion of chronic reinnervation(abnormal examined muscles/total examined muscles): cranial segment 78%,cervical segment: 91%,chest segment 85%,lumbosacral segment: 91%;6.In this study,14 Kennedy disease patients were tested by laboratory tests,10 cases of which had sex hormone abnormalities: 2 cases had abnormal luteinizing hormone,5cases had abnormal prolactin,4 cases had abnormal testosterone,and l case had abnormal follicle maturation hormone.6 cases of the tested patients had metabolic disorders: 4 cases had abnormal lipid metabolism,2 cases had elevated blood sugar,and 10 cases had elevated creatine kinase.7.This study examined the correlation between the number of repeats CAG exon 1 of AR gene and the age of onset and creatine kinase in 14 patients to determine whether it could be used to evaluate condition of kennedy disease.CAG has 6 repeats,ranging from39 to 54,with an average of 44.86±5.25 times.Analysis of genes and clinical phenotypes showed that the number of CAG repetitions was not correlated with age of onset(P>0.05),and creatine kinase(P>0.05).Conclusion1.Clinical manifestation of Kennedy disease is damage of lower motor neuron.The laboratory tests showed abnormal serum creatine enzymes and metabolism.The abnormal rate of prolactin in patients with sex hormone examination is higher.2.Abnormalities of neuroerve electrophysiology are chronic neurogenic changes and decreased sensory nerve amplitude.In addition,the study found that motor conduction of ulnar and peroneal nerves of Kennedy disease patients is more tired than other motor nerves;3.Gene testing is the gold standard for diagnostic Kennedy disease.