Motor Neurone Disease

New Forms of Genetic Testing Improve Diagnosis, Raise Questions

“Knowing, if not all, is almost all,” said Matthew Harms, a neurologist and neurophysiologist from Washington University in St. Louis, in his presentation on genetic testing for neuromuscular disorders at the 2014 MDA Clinical Conference, held in Chicago March 16-19.

MDA Awards $8.5 Million to 31 Neuromuscular Disease Research Projects

In its summer 2013 round of research grant awards, the Muscular Dystrophy Association aims to catalyze research progress in a dozen neuromuscular diseases, with an eye toward applying that knowledge to related muscle diseases, as well.

“A large number of our grants are investigating new therapeutic technologies,” notes Jane Larkindale, MDA's vice president of research. “These are 'platform' technologies, where successes can be transferred well beyond the specific disease in which they are developed and tested.”

Causes/Inheritance

Motor neurons
Muscle-controlling nerve cells (motor neurons) are located mostly in the spinal cord. Long, wirelike projections connect the motor neurons to muscles in the limbs and trunk. Normally, signals from the neurons to the muscles cause muscles to contract. In SMA, motor neurons are lost, and muscles can’t function.

Diagnosis

The first steps in diagnosis of a neuromuscular disease are usually an in-office physical examination and family history, with some simple tests to distinguish spinal muscular atrophy (SMA) from similar conditions (such as muscular dystrophy).

Signs and Symptoms

SMA linked to chromosome 5 (SMN-related), types 1-4

In SMA types 1 through 4, symptoms vary on a continuum from severe to mild, based on how much SMN protein there is in the nerve cells called motor neurons. (SMN stands for survival of motor neuron.) The more SMN protein there is, the later in life symptoms begin and the milder the course of the disease is likely to be. 

Forms of SMA

SMA linked to chromosome 5

Spinal muscular atrophy types 1 through 4 all result from a single known cause — a deficiency of a protein called SMN, for "survival of motor neuron."

Deficiency of SMN protein occurs when a mutation (flaw) is present in both copies of the SMN1 gene — one on each chromosome 5. Normally, most of the protein made from SMN1 genes is full-length and functional, but when mutations occur, little or no full-length, functional SMN protein is produced.

Overview

What is spinal muscular atrophy?

Muscles affected in SMA
The muscles closer to the center of the body (proximal muscles) are usually more affected in spinal muscular atrophy than are the muscles farther from the center (distal muscles).

Amyotrophic Lateral Sclerosis

Description: 

A diagnosis of amyotrophic lateral sclerosis (ALS) does not mean an end to your hopes and dreams. Changes, challenges and adaptations lay ahead, but also opportunity, fulfillment, joy and hope for a future free of this devastating disease.