Is there a relationship between ACTN3 R577X gene polymorphism and sarcopenia?

BACKGROUND AND AIMS: The alpha-actinin (ACTN) genes are important structural components of the sarcomere. Sarcopenia is a common geriatric syndrome characterized by morbidity and mortality. Our study aimed to examine the relationship between the ACTN3 R577X gene and sarcopenia in community-dwelling Turkish adults. METHODS: We designed a cross-sectional study among the patients aged ≥ 65 years admitted to the geriatric outpatient clinic. We recorded the general characteristics of the patients. We used the Jamar hand dynamometer to evaluate handgrip strength. Body composition was estimated using bioimpedance analysis. Sarcopenia was diagnosed according to the European Working Group on Sarcopenia in Older People2 criteria with population-specific cutoffs. We performed analyses of low muscle mass (LMM) with skeletal muscle mass index adjusted for body mass index [SMMI(BMI)]. We further categorized the SMMI(BMI) cutoffs into tenths. The analyzes were performed according to the 90th percentile SMMI(BMI) cutoffs. Peripheral blood samples were collected to determine the ACTN3 genotypes. RESULTS: 197 participants were included [mean age: 76.3 ± 6.1 years, 151 (76.6%) women]. The proportions of the ACTN3 genotypes were as follows: RX (45.1%) > RR (31%) > XX (23.9%). The significant difference between genotypes was found only for low SMMI(BMI) according to the 90th percentile (p = 0.025). In multivariate analysis, only gender (female) was independently associated with LMM. CONCLUSION: We did not find any association between ACTN3 R577X gene polymorphism and probable sarcopenia, confirmed sarcopenia and LMM. Besides, much more research is needed to reveal how ethnicity affects the muscles of older adults with ACTN3 R577X gene polymorphism.

HLA B-27 subtypes in Turkish patients with spondyloarthropathy and healthy controls.

The frequency and the distribution of HLA-B27 subtypes in spondylarthropathy (SpA) patients and controls were investigated in a sample Turkish population. B27 subtyping was performed by PCR-SSP method in two groups: 49 unrelated HLA-B27 positive Turkish patients with the diagnosis of SpA according to the European Spondyloarthropathy Study Group Criteria, and 55 HLA-B27 positive healthy controls. The frequency of HLA-B*27 was 2.6% in the Turkish population, and B*2705 was the predominant allele among patients with SpA. The difference was mainly between male patients and male controls The proportion of B*2705 among B27-positive patients and controls was significantly different (P=0.02). Our study supports other reports from different populations which showed that B*2705 and B*2702 were more frequent in Caucasian patients with SpA.

HLA-DRB1*15 and pediatric aplastic anemia.

We report a positive association between HLA-DRB1*15 (p= 0.0002) in Turkish patients with pediatric severe aplastic anemia (SAA) and a paradoxically favorable influence of the susceptibility marker on the clinical response to immunosuppressive therapy. These findings point to an immune mechanism mediated by DRB1*15 in SAA which confers responsiveness to treatment.