What is congenital fiber-type disproportion (CFTD)?

Updated: Mar 11, 2019
  • Author: Matthew Harmelink, MD; Chief Editor: Amy Kao, MD  more...
  • Print

Congenital fiber-type disproportion (CFTD) has as the main pathologic hallmark small type-1 muscle fibers. The original definition requires that type-1 fibers are 12% smaller in diameter than type-2 fibers, although often the difference is closer to 50%. Other common features are type-1 fiber predominance and reduced or absent type-2B fibers.

This term was initially coined to describe a group of infants with small type-1 muscle fibers and the clinical syndrome of hypotonia and diffuse weakness that may improve with age. Other clinical features can include facial, bulbar, and respiratory weakness; short stature; low body weight; multiple joint contractures; scoliosis; long, thin face; and high arched palate. Ophthalmoplegia, cardiac disease, and intellectual disability are rare. Mutations in several genes can cause CFTD.

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!