TRPV4-Related Neuropathies

Gene: TRPV4

Protein: transient receptor potential cation channel, subfamily V, member 4

Clinical Characteristics

Congenital Distal Spinal Muscular Atrophy

  • Congenital weakness of lower limbs
  • Weakness of pelvic girdle and trunk may or may not be present
  • Congenital contractures may or may not be present
  • Nonprogressive

Scapuloperoneal Spinal Muscular Atrophy (Also Known as Neurogenic Scapuloperoneal Amyotrophy)

  • Congenital amyoplasia
  • Progressive scapuloperoneal atrophy and weakness
  • Laryngeal palsy

Hereditary Motor and Sensory Neuropathy, Type IIC (Also Known as Charcot-Marie-Tooth Disease Type 2C)

  • Progressive weakness of limb, diaphragm, intercostal and laryngeal muscles
  • Sensory involvement may be mild or asymptomatic

Inheritance pattern: Autosomal dominant

What Can Be Learned From This Test

Mutations in exons 3, 5 and 6 of TRPV4 have been associated with the three neuromuscular disorders listed above, which show overlap in their clinical symptoms. Testing can be performed by sequencing exons 3, 5 and 6, or by sequencing the entire coding region. This will detect point mutations, small deletions and small insertions. It will not detect a partial or whole gene deletion or duplication.

TRPV4 is the only gene known to be associated with these specific disorders. A negative test does not rule out a genetic cause of neuromuscular problems, as there are many other genes associated with different types of neuromuscular disorders.

Certain mutations in exons 6 and 11 through 16 of TRPV4 have been associated with three specific types of autosomal dominant skeletal dysplasias. One of these mutations may be identified during this test. This will be reported to the ordering provider.

Sample Requirements

Draw 2ml–4ml of blood in EDTA/purple-top tube (minimum of 1ml–2ml for infants).

Turnaround time: 10-14 business days

CPT Codes and Cost

Sequencing (Exons 3, 5 & 6 Only)

  • Code: 81479
  • Cost: $325

Full Gene Sequencing

  • Code: 81479
  • Cost: $1,450

Additional Information