What is congenital fiber-type disproportion (CFTD)?

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

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.


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