Kennedy’s Disease and ALS

Even though Kennedy’s Disease (SBMA) is becoming more widely known in the medical community, I still receive calls or emails requesting additional information on the condition after a person has been initially diagnosed with Amyotrophic Lateral Sclerosis (ALS). One major difference between the two conditions is that SBMA effects the lower motor neurons where ALS effects both the upper and lower motor neurons.

Sunday I received such a call. A woman in her late 70s was experiencing swallowing problems and the occasional fall. Her doctor diagnosed the health concern as Familial ALS (FALS). Since she never experienced any symptoms until the past year, she did her own research and came across Kennedy’s Disease. Several symptoms were similar to ALS and a few she felt fit her better. 

The average age of onset for ALS is in the mid-to-late 50s, however, there have been cases where symptoms first appeared in the patient’s 70s. The ALS Association has a good PDF report on the Epidemiology of ALS here.  To learn more about ALS, follow this link to the ALS Association.

I also ran across an interesting 2008 report on how Kennedy’s Disease mimics ALS. The summary is shown below with a link to the actual report. 

Kennedy Disease Mimics Amyotrophic Lateral Sclerosis:
A Case Report
Mu-Hui Fu, Min-Yu Lan, Jia-Shou Liu, Shung-Lon Lai, Shun-Sheng Chen,
and Yung-Yee Chang

Abstract- Kennedy disease (KD) is an X-linked inherited motor neuron disease that is often accompanied by androgen insensitivity. Its estimated incidence in the US is approximately 1 case in 40,000 men. KD has also been reported in individuals of different racial backgrounds, especially in Japanese but the prevalence rate in Taiwan has not been fully investigated. Here we report a case of KD definitely diagnosed by abnormal expansion of a polymorphic tandem cytosine-adenine-guanine (CAG) triplet repeat in the first exon of the androgen receptor gene. The direct genotyping from polymerase chain reaction product is subsequently performed utilizing capillary electrophoresis. The patient’s neurological conditions mimic amyotrophic lateral sclerosis (ALS). Since these two diseases have different etiologies and prognosis, it reminds us the necessity to rule out KD in face with a suspected male case of ALS.

Download the six page report here

ALS Image: ALS Association

KD Image: MDA