Fukuyama congenital muscular dystrophy

Last revised by Yuranga Weerakkody on 18 Aug 2019

Fukuyama congenital muscular dystrophy (FCMD) is a form of congenital muscular dystrophy.

FCMD is almost exclusively found in Japan where it has an incidence of 2-4 per 100,000 infants and is the second most common muscular dystrophy after Duchenne muscular dystrophy 1,2. However, it has also been reported as far as Netherlands and Australia in patients without Japanese ancestry 1.

Affected infants are hypotonic and have generalized symmetric weakness affecting proximal, distal, and facial muscles by 9 months of age 1,3. These features ultimately progress into childhood, and are accompanied by developmental delay and intellectual disability 1,3. Other features such as skeletal muscle pseudohypertrophy, joint contractures, and epilepsy are also seen in most patients 1,3.

FCMD is inherited in an autosomal recessive pattern, and is due to a mutation in the fukutin-related protein (FKTN) gene 1-3. This gene is located on the q arm of chromosome 9 and as its name suggests encodes for the protein fukutin, which has a role in protecting skeletal muscle and organizing early brain development 1-3.

Brain MR features are most commonly described, and include:

  • polymicrogyria
    • cerebral polymicrogyria is seen in nearly all patients, typically in the frontal and parietal lobes 4,5
    • cerebellar polymicrogyria is seen in approximately 90% of patients, typically in the superior semilunar lobule 4,5
  • pachygyria (type II (cobblestone complex) lissencephaly): in approximately half of patients, typically involving the temporal and occipital lobes 4,5
  • white matter changes: most commonly diffuse prolonging of T1 and T2 signal in the white matter, but may also be patchy, spotty or equivocal 4-6

Unlike Walker-Warburg syndrome, one of its main differentials, cerebellar dysplasia, retinal dysplasia and gyral malformations are not commonly appreciated in FCMD 7.

No disease-modifying therapy is available (as of 2017), and management relies on input from allied health services. 

This disorder is named after Yukio Fukuyama (1928-2014), a Japanese pediatric neurologist, who first described the condition in his 1960 seminal paper 1,8.

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Cases and figures

  • Case 1
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