Spinal and Bulbar Muscular Atrophy (SBMA) – Kennedy’s Disease
Spinal and Bulbar Muscular Atrophy (SBMA) – Kennedy’s Disease
This information is for you if you have been recently diagnosed with SBMA, which is also commonly referred to as Kennedy’s Disease.
SBMA is a rare inherited neuromuscular condition. It is also sometimes known as:
- X-linked motor neuron disease
- X-linked recessive bulbospinal neuropathy
- X-linked SBMA
It is an adult onset form of SMA that mainly affects men. It is estimated that about 1 in 40,000 people have the genetic fault that causes the condition and, because it is relatively rare, SBMA is often initially misdiagnosed or goes undiagnosed for years.
SBMA 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 SBMA are described in more detail in the information published by the MND Associations and Kennedy’s Disease UK (see below under Support and Resources).
The affected gene is:
- The Androgen Receptor (AR) gene, on the X sex chromosome¹‾².
Further information about the AR Gene >
SBMA has an X-linked Recessive inheritance pattern.
1. La Spada et al. (1991) ‘Androgen receptor gene mutations in X-linked spinal and bulbar muscular atrophy’, Nature, 352, pp. 77–79.
2. https://www.omim.org/entry/313200 (last accessed 21st August 2024)
Version: 2
Author: SMA UK Information Production Team
Last updated: August 2022
Next full review date September 2024
Links last checked: August 2024
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