Spinal and Bulbar Muscular Atrophy (SBMA) – Kennedy’s Disease
This information is for if you have been recently diagnosed with SBMA - Kennedy's Disease.
What is SBMA-Kennedy’s Disease?
Kennedy’s Disease is a rare inherited neuromuscular condition. It’s also known as:
- X-linked motor neuron disease
- X-linked recessive bulbospinal neuropathy or
- X-linked spinal and bulbar atrophy
It’s an adult onset, form of SMA that mainly affects men. It’s estimated that 1 in 40,000 people have the genetic fault that causes it and, because it’s relatively rare, Kennedy’s Disease is often initially misdiagnosed or goes undiagnosed for years.
What are the symptoms and effects?
Kennedy’s Disease causes progressive weakening and wasting of the muscles, particularly in the arms and legs. This is due to the degeneration of lower motor neurons within the spinal cord and brainstem. It also causes hormonal changes. Symptoms and effects of Kennedy’s Disease are described in more detail in the information published by the MND Associations and Kennedy’s Disease UK (see below).
Which gene is affected?
Some of the genes that cause rare forms of SMA are associated with more than one condition, so please be aware that the website links suggested might provide information that is not just about SMA.
The affected gene is:
- The Androgen receptor (AR) gene, on the X sex chromosome1.
Further information can be found here.
Kennedy’s Disease has an X-linked Recessive inheritance pattern.
Support and resources
Kennedy’s Disease UK
Phone: 01604 250505
(search for Kennedy’s Disease)
Author: SMA UK Information Production Team
Published: September 2018
Last updated: March 2019
Next full review date September 2021
1. La Spada et al. (1991) ‘Androgen receptor gene mutations in X-linked spinal and bulbar muscular atrophy’, Nature, 352, pp. 77–79.
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