Case Report

Congenital muscular dystrophy with characteristic radiological findings similar to those with Fukuyama congenital muscular dystrophy

Ajay Garg, Sheffali Gulati*, Vipul Gupta, Veena Kalra* Departments of Neuroradiology and *Pediatrics, AIIMS, New Delhi, India.

Fukuyama congenital muscular dystrophy (FCMD) is the quired social smile at 2 months, partial head control at 8 months, started sitting with support at 9 months and sitting without support most common congenital muscular dystrophy in Japan and at 18 months. He had no seizures. On examination, he had head lag there are isolated reports of non-Japanese patients with and hypotonia. Power was 3/5 in all limbs. Deep tendon jerks were FCMD. We report an Indian patient with congenital muscu- not elicitable. There was no muscle . The ophthalmic lar dystrophy and characteristic radiological findings similar examination, visual evoked potentials, motor nerve conduction stud- to those with FCMD. ies and EEG were normal. Electromyography showed a myopathic pattern. Serum creatine kinase was elevated at 2970 U/l (normal Key Words: Fukuyama congenital muscular dystrophy, con- 24-190 U/l). genital muscular dystrophy Cranial MRI revealed disorganized cerebellar folia with multiple cysts within vermis and cerebellar hemispheres (Figures 1a and 1b). There was marked pontine, and inferior vermian and fused midbrain colliculi (Figure 2a). The frontal lobes had shallow sulci Introduction and a bizarre pattern of the sulci parallel to each other without per- pendicular sulci (Figures 2a and 2b). There was ventriculomegaly and abnormal increased signal in periventricular white matter. The Congenital muscular dystrophy (CMD) is a heterogeneous corpus callosum had a bizarre configuration, though was not hypo- group of disorders characterized by muscular hypotonia of plastic. In view of cortical with characteristic distribution, prenatal onset and the histologic features of muscular dystro- cerebellar abnormalities, preserved general configuration of the brain phy.1 Based on the clinical, immunohistochemical, and genetic and normal ophthalmologic examination, a diagnosis of FCMD was findings, eight different forms have been characterized geneti- considered. Muscle biopsy and genetic analysis could not be done. cally, and additional forms have been identified clinically.2 The patient succumbed to respiratory infection and autopsy was Muscle-eye-brain (MEB), Walker-Warburg syndrome denied. (WWS), and Fukuyama congenital muscular dystrophy (FCMD) are clinically similar autosomal recessive disorders Discussion characterized by congenital muscular dystrophy, lissencephaly, and eye anomalies.3 FCMD is the most common congenital Mutations of glycosylation enzymes have been commonly muscular dystrophy in Japan. Isolated cases of FCMD in non- suggested in congenital muscular dystrophies (CMDs) with Japaneses have been reported in other countries.4-7 We report brain malformation and ocular involvement. These include the an Indian patient of congenital muscular dystrophy with char- Muscle-eye-brain disease (MEB), Walker-Warburg syndrome acteristic radiological findings similar to those with FCMD. (WWS), and Fukuyama congenital muscular dystrophy (FCMD) and the CMD due to fukutin-related protein (FKRP) Case Report defects.3 The causative genes for these disorders are assumed to play a role in the glycosylation of dystroglycan, whose disrup- A three-and-a-half-year-old boy, born out of a non-consanguine- tion can result in a decreased integrity of the dystrophin-glyco- ous marriage, presented with hypotonia and developmental delay since protein complex and can lead to the dystrophic pathology of birth. He was unable to stand, speak, and was incontinent. He ac- skeletal muscles and brain malformation.3

Sheffali Gulati Assistant Professor, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi - 110029, India. E-mail: [email protected]

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The severity of the clinical and radiological findings of the reported in a Turkish patient with WWS phenotype.9 Simi- present patient is most similar to that in typical FCMD cases. larly, mutations in the FKRP give rise to a broad clinical spec- Patients with FCMD manifest weakness of the facial and limb trum that ranges from mild muscular dystrophy (LGMD2I) muscles, and general hypotonia that usually appears before to the more severe form (MDC1C), which in some cases is nine months of age.1,8 Most patients are never able to walk. also associated with intellectual impairment and cerebellar Seizures occur in nearly half of the cases.1 Severe metal retar- cysts.10 Thus the term FCMD should be used to describe the dation is observed in all cases. The patients survive beyond clinical phenotype, and not the genotype of individual patients. infancy, and ocular manifestations are rare and usually mild. We diagnosed the present patient as having FCMD based on Patients usually become bedridden before 10 years of age due these considerations, on the clinical severity, including the find- to generalized muscle and joint contracture, and most ings on MR images as discussed below. of them die by 20 years of age.1 These features are largely The most common and characteristic changes in the central milder than the clinical course of patients with WWS and nervous system are brain malformations, which include MEB, but are more severe than those with FKRP defects. On polymicrogyria, pachygyria, and agyria of the cerebrum and the other hand, what is confusing is the overlap between the cerebellum (cobblestone cortex) lacking neuronal lamination genotype-phenotype correlations of the disorders. A ho- of the normal six-layered cortex.3,4,11 In brain MR examina- mozygous nonsense mutation in the Fukutin gene has been tion, all patients show polymicrogyria, and approximately half

(a) (b)

Figure 1: Axial T1 (a) and T2WI (b) show disorganized cerebellar folia with numerous intraparenchymal cysts, hypoplastic pons and enlarged fourth ventricle. Focal area of hyperintensity is seen in the right temporal lobe white matter on T2WI (white arrow) (b)

(a) (b)

Figure 2: Sagittal T1WI (a) shows marked pontine hypoplasia (long black arrow), fusion of midbrain colliculi (small black arrow), hypoplastic inferior vermis and abnormal cyst within vermis. The cortical architecture of the frontal lobe is abnormal as evidenced by shallow sulci and bizarre pattern of the sulci parallel to each other without perpendicular sulci (white arrow). This contrasts with normal parieto-occipital sulci. Axial T1WI (b) of the cerebrum shows slightly thick and bumpy cortices with abnormal gyration in the frontal lobes. The temporo-occipital cortices show no abnormalities

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CMYK 497 Garg A, et al: Congenital muscular dystrophy the patients show pachygyria. These two types of cortical In summary, the index patient presented with muscular hy- are present in characteristic distributions: the potonia and developmental delay. He had normal ophthalmo- former demonstrates frontal lobe involvement in all and logic examination. MR imaging showed disorganized cerebel- parietotemporal lobe involvement in some, whereas the latter lar folia with cysts, marked pontine hypoplasia, bilateral frontal involves the temporo-occipital lobes.4 Most patients show pro- cortical dysgenesis, ventriculomegaly, fused midbrain colliculi longed T1 and T2 signal in the white matter, which is thought and white matter T2-hyperintensity. In view of cortical dys- to be due to delayed myelination.3 Various degrees of plasia with characteristic distribution, cerebellar abnormali- ventriculomegaly and hypoplasia of the pons can be seen some- ties, preserved general configuration of the brain and normal times.3,4 ophthalmologic examination, a diagnosis of FCMD was made. Cerebellar polymicrogyria depicted as disorganized cerebel- We speculate that this disorder may be more common than lar foliation accompanying cysts is found in more than 90% is generally recognized and that the use of MR imaging and of the patients.4 Both lesions tend to be located in the mid increased awareness among radiologists will help to identify portion and dorsal surface of the hemisphere, particularly in these patients more readily. the superior semilunar lobule. WWS and MEB can also cause similar MR findings. However, FCMD is associated with less References severe gyral malformations and cerebellar anomalies than WWS, and ocular involvement is less severe in FCMD.11 Pa- 1. Fukuyama Y, Osawa M, Suzuki H. Congenital progressive muscular dystrophy tients with WWS show diffuse cerebral cobblestone cortex, of the Fukuyama type-clinical, genetic and pathological considerations. Brain Dev 1981;3:1-29. absence of cerebral and cerebellar myelin, cerebellar 2. Muntoni F, Guicheney P. 85th ENMC International Workshop on Congenital polymicrogyria (with or without cysts), hydrocephalus, pon- Muscular Dystrophy 6th International CMD Workshop 1st Workshop of the Myo- Cluster Project ‘GENRE’ 27-28th October 2000, Naarden, The Netherlands. tine and cerebellar vermian hypoplasia.11 The septum pelluci- Neuromuscul Disord 2002;12:69-78. dum is absent, and the corpus callosum, basal ganglia and 3. Toda T, Kobayashi K, Takeda S, Sasaki J, Kurahashi H, Kano H, et al. Fukuyama-type congenital muscular dystrophy (FCMD) and alpha- thalami are markedly hypoplastic. Patients with MEB show dystroglycanopathy. Congenit Anom Kyoto 2003;43:97-104. cerebellar polymicrogyria (with or without cysts), absence of 4. Aida N. Fukuyama congenital muscular dystrophy: A neuroradiologic review. Magn Reson Imaging 1998;8:317-26. the septum pellucidum, diffuse cerebral cortical dysplasia, 5. Stern LM, Albertyn L, Manson JI. Fukuyama congenital muscular dystrophy pontine and cerebellar vermian hypoplasia, patchy in two Australian female. Dev Med Child Neurol 1990;32:808-13. 6. Topaloglu H, Renda Y, Gogus S, Benli S, Nurlu G, Yildirim M. Fukuyama type hypomyelination, and variable callosal hypogenesis and hy- congenital muscular dystrophy in a Turkish child. Can J Neurol Sci drocephalus. 1990;17:149-50. 7. Peters AC, Bots GT, Roos RA, van Gelderen HH. Fukuyama type congenital Traditionally, the diagnosis is based on pathologic evidence muscular dystrophy-two Dutch siblings. Brain Dev 1984;6:406-16. of muscular dystrophy in the biopsy specimen obtained in the 8. Toda T, Kobayashi K, Kondo-Iida E, Sasaki J, Nakamura Y. The Fukuyama congenital muscular dystrophy story. Neuromuscul Disord 2000;10: 4 appropriate clinical context. Nevertheless, the presence of 153-9. brain malformation can be overlooked in the presence of mus- 9. de Bernabe DB, van Bokhoven H, van Beusekom E, Van den AW, Kant S, Dobyns WB, et al. A homozygous nonsense mutation in the Fukutin gene causes cular symptoms, and a muscle biopsy does not provide spe- a Walker-Warburg syndrome phenotype. J Med Genet 2003;40:845-8. cific evidence for FCMD beyond the mere diagnosis of mus- 10. Topaloglu H, Brockington M, Yuva Y, Talim B, Haliloglu G, Blake D, et al. FKRP gene mutations cause congenital muscular dystrophy, mental retarda- 4 cular dystrophy. The diagnosis of FCMD can be facilitated tion, and cerebellar cysts. Neurology 2003;60:988-92. with MRI, which readily demonstrates a variety of brain mal- 11. Barkovich AJ. Neuroimaging manifestations and classification of congenital muscular dystrophies. AJNR Am J Neuroradiol 1998;19:1389-96. formations in FCMD, the constellation of which is considered 4 to be diagnostic of this entity without a muscle biopsy. Accepted on 21.01.2004.

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