Research Article: Werner syndrome: a model for sarcopenia due to accelerated aging

Date Published: July 19, 2017

Publisher: Impact Journals LLC

Author(s): Masaya Yamaga, Minoru Takemoto, Mayumi Shoji, Kenichi Sakamoto, Masashi Yamamoto, Takahiro Ishikawa, Masaya Koshizaka, Yoshiro Maezawa, Kazuki Kobayashi, Koutaro Yokote.

http://doi.org/10.18632/aging.101265

Abstract

Werner syndrome (WS) is a rare inheritable progeroid syndrome caused by a mutation in the WRN gene. Although WS has been described as a characteristic appearance of very slender extremities with a stocky trunk, few studies have investigated the loss of muscle mass, fat mass distribution (body composition), and mobility according to age and sex. Therefore, the aim of this study was to precisely describe the body composition in WS. Nine Japanese patients with WS (four males and five females; mean age 48±8.8 years) were recruited. Body composition was examined by dual-energy X-ray absorptiometry and computed tomography (CT). The hand grip strength and mobility were evaluated using the two-step test, stand-up test and 25-question geriatric locomotive function scale. The mean skeletal muscle index (SMI) was 4.0±0.6 kg/m. SMI of all patients met the criteria of sarcopenia, even though some patients were aged < 40 years. All patients also showed deceased mobility. In conclusion, these results indicate that all patients with WS, even those aged < 40 years, had already lost muscle mass to the level of sarcopenia. Continued research on sarcopenia in WS might facilitate the discovery of novel mechanisms and development of new treatment strategies for sarcopenia.

Partial Text

Werner syndrome (WS) is a representative hereditary progeroid syndrome [1] with a high incidence in Japan [2]. It is frequently accompanied with metabolic disorders, such as diabetes and dyslipidemia [3, 4], vascular disease [5], and malignancy [6]. Patients with WS also show characteristic appearances of short stature, light body weight, and a so called bird-like face in which the nasal bridge appears to be pinched and the subcutaneous tissue is diminished [7]. Physicians with experience in treatment of WS may doubt the presence of the disease even if the patient presents with a characteristic bird-like face and a high pitched, squeaky, and/or hoarse voice. The skin of these patients is usually atrophic and tight. Clavus, callus, or intractable ulcers of the feet are also frequently observed [8]. Patients with WS have very slender extremities and have been described as a dried tree with a stocky trunk [7]. The appearance of these patients is sometimes referred to as Cushing or Klinefelter syndrome-like central obesity, although a few reports describe anomalies of muscle mass, fat mass distribution (body composition), and mobility, which differ according to age and sex. Therefore, the aim of this study was to precisely describe the body compositions of patients with WS.

This is the first report to precisely evaluate the body composition and mobility of patients with WS of different ages and both sexes. All patients met the criteria for sarcopenia even though some were aged <40 years and sarcopenia seemed to appear before the accumulation of VFA.   Source: http://doi.org/10.18632/aging.101265

 

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