0.05). The average SV of premature systoles is 35% of sinus beats. Premature systoles less than 5 beats/min may cause and average drop of 5% of cardiac output (CO), While the premature systoles increased to 10-20 beats/min, the CO would be dropped further of 10-19%. there Was a high linear correlation between sr of all premature systoles and the coupling interval premature systoles (p

OBJECTIVE: To explore the clinical signification of screening 16 target deafness mutations in GJB2, GJB3, SLC26A4, WFS1 and mitochondrial DNA 12S rRNA in 135 children patients with non-syndromic sensorineural hearing loss (NSHL) in Zibo City, Shandong province. METHOD: Peripheral blood samples of 135 subjects in the study diagnosed as NSHL were collected; Polymerase chain reaction (PCR) and direct sequencing were used to analyze the 16 mutation spots. RESULT: Sixty-two cases of 135 patients (45.9%, 62/135) were found out to be carries of at least one pathogenic gene mutation. Among them, 24 cases (17.8%, 24/135) had two mutated alleles (homozygote and compound heterozygote), and 38 cases (28.1%, 38/135) were single mutant carriers. Among all the children patients, 30 cases (22. 2%, 30/135) had SLC26A4 mutations, and 19 cases (14.1%, 19/135) had GJB2 mutations. In the study 86 Mutant alleles were detected, and the allele frequency of SLC26A4 c. 766_2A > G and GJB2 c. 235delC was 11.11% (30/270) and 8.5% (23/270) respectively. The allele frequency of SLC26A4 c. 2168A > G and WFS1 c. 2158A > G is 2.6% (7/270). CONCLUSION SLC26A4 mutation is the primary cause of the patients with NSHL in this study, and GJB2 mutation is the secondary. The most common mutant form is c. 766_2A of SLC26A4, and the second is c. 235delC of GJB2. GJB3 and WFS1 mutations were detected, whereas mtDNA mutations were not found out in this study.
Alleles ; Child ; Connexins ; DNA Mutational Analysis ; DNA, Mitochondrial ; Deafness ; Gene Frequency ; Hearing Loss ; Hearing Loss, Sensorineural ; genetics ; Heterozygote ; Homozygote ; Humans ; Mitochondria ; Mutation ; Polymerase Chain Reaction ; RNA, Ribosomal