Back
Publications about genetic testing for neurological disorders
  1. NGS Panel – Genetic Testing for Amyotrophic Lateral Sclerosis (ALS)

Amyotrophic Lateral Sclerosis (ALS)

May 11, 2018

Disease summary:

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder characterized by the degeneration of the upper and lower motor neurons. Most cases appear to be sporadic, but 5-10% of cases have a family history of the disease (FALS) 1. To date, more than a dozen causative genes have been identified in hereditary ALS and more than 30 potential causative or disease-modifying genes have also been identified 2, 3


Autosomal dominant, autosomal recessive, X-linked dominant

Prevalence: 4-8/100,000 1, 4

Major clinical symptoms 1, 5:

  • Asymmetric focal weakness of the extremities (stumbling or poor handgrip)
  • Dysarthria
  • Dysphagia)
  • Muscle fasciculations
  • Muscle cramps

Presence of all of the following clinical features 1, 5:

  • Signs of lower motor neuron (LMN) degeneration by clinical, electrophysiologic, or neuropathologic examination
  • Signs of upper motor neuron (UMN) degeneration by clinical examination
  • Progressive spread of symptoms or signs within a region or to other regions
  • Absence of evidence of other diseases that could cause UMN or LMN degeneration and/or explain the electrophysiologic or neuropathologic results

For familial cases of ALS: Identification of a heterozygous pathogenic variant in one of the following genes 2, 3 (Table 1):

  • SOD1 (frequency of pathogenic variants approximately 20%) 1-3
  • C9orf72 (23%-30%) 1-3
  • TARDBP (1%-4%) 1-3
  • FUS (4%) 1-3
  • SETX, FIG4, ANG and others (Table 1).

There is no cure for ALS to date, but symptomatic treatment can relieve symptoms 1, 6.

  • Care by a multidisciplinary team (neurologist, pulmonologist, speech, physical and occupational therapist, nutritionist, psychologist, social worker, and genetics professional) 6.
  • The two FDA–approved drugs riluzole and edaravone, slow the progression of symptoms
  • Antidepressants, bensodiazepines, baclofen, for muscle cramps and spasticity
  • Ventilator assistance
  • Spinal and bulbar muscular atrophy
  • Spinal muscular atrophy
  • Distal hereditary motor neuronopathy type VIIB
  • Primary lateral sclerosis
  • Hereditary spastic paraplegia
  • Hexosaminadase A deficiency
  • Inclusion body myopathy associated with Paget disease of bone and/or frontotemporal dementia 

 

To confirm/establish the diagnosis, CENTOGENE offers the following testing strategy for ALS using NGS Panel Genomic:

Step 1: Whole genome sequencing from a single filter card (drop of blood), covering the entire genic region (coding region, exon/intron boundaries, intronic and promoter) for all the genes included in the ALS panel. Copy Number Variants analysis derived from NGS data is also included.

Step 2: If no pathogenic variant is identified in Step1, continue with bioinformatics analysis covering genes that are either implicated or associated with overlapping phenotype or similar pathways.   

  • Individuals with a positive family history of ALS
  • Individuals with most common symptoms of ALS (regardless of family history)

Confirmation of a clinical diagnosis through genetic testing of ALS can allow for genetic counseling and may direct medical management.


Table 1. Overview of genes in Amyotrophic lateral sclerosis panel

Gene OMIM (Gene) Associated diseases (OMIM) Inheritance CentoMD® exclusive variant numbers (++)