Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Review
. 2024 Jan 28:34:100495.
doi: 10.1016/j.ensci.2024.100495. eCollection 2024 Mar.

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

Dante J Bellai  1 , Mark G Rae  1
Affiliations
Review

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

Dante J Bellai et al. eNeurologicalSci. .

Abstract

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.

Keywords: Activities of daily living; Androgen receptor gene; CAG repeat; Compound muscle action potentials; Electromyography; Kennedy's disease; Nerve conduction studies; Spinal bulbar muscular atrophy.

PubMed Disclaimer

Conflict of interest statement

None. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Figures

Unlabelled Image
Fig. 1
Flow chart of screening, and criteria for inclusion and exclusion of articles [8].
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Pradat P.-F., Bernard E., Corcia P., Couratier P., Jublanc C., et al. The French national protocol for Kennedy’s disease (SBMA): consensus diagnostic and management recommendations. Orphanet J. Rare Dis. 2020 Dec;15(90):1–21. doi: 10.1186/s13023-020-01366-z. - DOI - PMC - PubMed
    1. Lund A., Udd B., Juvonen V., Andersen P.M., Cederquist K., Davis M., et al. Multiple founder effects in spinal and bulbar muscular atrophy (SBMA, Kennedy disease) around the world. Eur. J. Hum. Genet. 2001 Jun;9(6):431–436. doi: 10.1038/sj.ejhg.5200656. - DOI - PubMed
    1. Grunseich C., Fischbeck K.H. Spinal and bulbar muscular atrophy. Neurol. Clin. 2015 Nov;33(4):847–854. doi: 10.1016/j.ncl.2015.07.002. - DOI - PMC - PubMed
    1. Finsterer J., Soraru G. Onset manifestations of spinal and bulbar muscular atrophy (Kennedy’s disease) J. Mol. Neurosci. 2016 Mar;58(3):321–329. doi: 10.1007/s12031-015-0663-x. - DOI - PubMed
    1. Atsuta N. Natural history of spinal and bulbar muscular atrophy (SBMA): a study of 223 Japanese patients. Brain. 2006 Apr 13;129(6):1446–1455. doi: 10.1093/brain/awl096. - DOI - PubMed

LinkOut - more resources