Friday 18 August 2017

Fukuyama Congenital Muscular Dystrophy MRI

Hypotelorism, convergent squint
Delayed milestones.

MRI study of brain shows:
Bilateral symmetric frontal lobar Poly micro gyria.
Diffuse cerebral cortical atrophy with mild dilatation of lateral ventricles.
Bilateral Cerebral Periventricular as well as sub cortical white matter show symmetric confluent T2 hyperintensity with white matter paucity suggestive of hypo myelination.
Marked atrophy of Brainstem particularly Pons, hypo plasia with a typical midline cleft.
Bilateral cerebellar hemispheres show multiple T2 hyperintense small cysts with micro folia attributed to an associated cerebellar dysplasia, Polymicrogyria with mild hypo plasia of cerebellar vermis. Postero fossa normal sized.
Bilateral Basal ganglia and thalami spared.

Imaging diagnosis:
Fukuyama Congenital Muscular Dystrophy.
Differential diagnosis: 
Walker-Warburg syndrome.

Reference : 
American Society of Neuroradiology : Fukuyama Congenital Muscular Dystrophy Fukuyama-congenital-muscular-dystrophy

Fukuyama Congenital Muscular Dystrophy

Named after Yukio Fukuyama (1928-2014), a Japanese pediatric neurologist, who first described the condition in his 1960.

Exclusively found in Japan with an incidence of 2/4 per 100,000 infants and is the second most common muscular dystrophy after Duchenne muscular dystrophy. An autosomal recessive inherited disease due to a mutation in the fukutin-related protein (FKTN) gene on chromosome 9.

The disease onset typically occurs in early infancy. Initial symptoms may include a poor suck, weak cry, floppiness, symmetrical generalised muscle weakness and hypotonia. Facial myopathy may also be seen and increases with age. Developmental and speech delay occur in all individual with FCMD. Other symptoms include seizures, clinical features related to cardiomyopathy, and cardiac failure. Survival beyond 20 years is uncommon, and death usually occurs following respiratory complications.

Key Diagnostic Features on MRI are cerebral and cerebellar polymicrogyria with accompanying cysts, and ventricular dilatation. Uncommonly, agenesis of septum pellucidum can be seen.
Polymicrogyria typically seen in the frontal and parietal lobes. Pachygyria in approximately half of patients, typically involving the temporal and occipital lobes. Cerebellar polymicrogyria is seen in approximately 90% of patients. White matter changes patchy, spotty suggestive of dysmyelination. 

Walker-Warburg syndrome is one of its main differentials, in which cerebellar dysplasia is commonly seen, is not very common in Fukuyama congenital muscular dystrophy. 

Supportive therapy. Definitive treatment not available.