Forceps Minor Region Signal Abnormality “Ears of the Lynx”: An Early MRI Finding in Spastic Paraparesis with Thin Corpus Callosum and Mutations in the Spatacsin Gene (SPG11) on Chromosome 15

From the Department of Neurology and Neurosurgery (MR, PP, MAP, PC, JCM); Clínica Universitaria de Navarra, and the Neuroimaging (JI, BP); and Neurogenetics Laboratories (LS), Division of Neurosciences, Center for Applied Medical Research, University of Navarra, and the “Centro de Investigación Biomédica en Red (CIBER)” (PP, BP, JI, MAP, JCM), Pamplona, Spain.
Journal of neuroimaging: official journal of the American Society of Neuroimaging (Impact Factor: 3.36). 12/2008; 19(1):52 - 60. DOI: 10.1111/j.1552-6569.2008.00327.x

ABSTRACT ABSTRACTBACKGROUND AND PURPOSEA thin corpus callosum on magnetic resonance imaging (MRI) characterizes a type of autosomal recessive disorder with progressive spastic paraparesis and cognitive impairment. Known as Hereditary Spastic Paraparesis with Thin Corpus Callosum (HSP-TCC), it has been associated with mutations of the SPG11 gene. No other specific MRI findings have been reported.METHODS
We studied with MRI four patients from three families with HSP-TCC who had identified causal mutations in the SPG11 gene.RESULTSIn all individuals studied the region of the forceps minor of the corpus callosum, corresponding to the genu fibers, appeared bright on T2-weighted and dark on T1-weighted images. On axial sections, the frontal horn region bore a remarkable resemblance to the ears of a lynx, with the areas of abnormal signal reminiscent of the tufts of hair crowning the tips of the ears of this animal. Less specific findings included a box-shape appearance of the calloso-caudate angle and diffusely increased signal in the hemispheric white matter.CONCLUSION
Abnormal MRI signal in the region of the forceps minor of the corpus callosum is a characteristic early imaging finding of HSP-TCC with SPG11 mutations.

1 Bookmark
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Objective Hereditary spastic paraplegias (HSPs) are among the most genetically diverse inherited neurological disorders, with over 70 disease loci identified (SPG1-71) to date. SPG15 and SPG11 are clinically similar, autosomal recessive disorders characterized by progressive spastic paraplegia along with thin corpus callosum, white matter abnormalities, cognitive impairment, and ophthalmologic abnormalities. Furthermore, both have been linked to early-onset parkinsonism.Methods We describe two new cases of SPG15 and investigate cellular changes in SPG15 and SPG11 patient-derived fibroblasts, seeking to identify shared pathogenic themes. Cells were evaluated for any abnormalities in cell division, DNA repair, endoplasmic reticulum, endosomes, and lysosomes.ResultsFibroblasts prepared from patients with SPG15 have selective enlargement of LAMP1-positive structures, and they consistently exhibited abnormal lysosomal storage by electron microscopy. A similar enlargement of LAMP1-positive structures was also observed in cells from multiple SPG11 patients, though prominent abnormal lysosomal storage was not evident. The stabilities of the SPG15 protein spastizin/ZFYVE26 and the SPG11 protein spatacsin were interdependent.InterpretationEmerging studies implicating these two proteins in interactions with the late endosomal/lysosomal adaptor protein complex AP-5 are consistent with shared abnormalities in lysosomes, supporting a converging mechanism for these two disorders. Recent work with Zfyve26−/− mice revealed a similar phenotype to human SPG15, and cells in these mice had endolysosomal abnormalities. SPG15 and SPG11 are particularly notable among HSPs because they can also present with juvenile parkinsonism, and this lysosomal trafficking or storage defect may be relevant for other forms of parkinsonism associated with lysosomal dysfunction.
    Annals of Clinical and Translational Neurology. 05/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: Although the "face of the giant panda" sign on magnetic resonance imaging (MRI) is traditionally considered to be characteristic of Wilson disease, it has also been reported in other metabolic disorders. This study describes the characteristic "giant panda" sign on MRI in a child with Leigh disease. The diagnosis was based on the history of neurological regression; examination findings of oculomotor abnormalities, hypotonia, and dystonia; raised serum lactate levels; and characteristic brain stem and basal ganglia signal changes on MRI. The midbrain and pontine tegmental signal changes were consistent with the "face of the giant panda and her cub" sign. In addition to Wilson disease, metabolic disorders such as Leigh disease should also be considered in the differential diagnosis of this rare imaging finding.
    Journal of child neurology 04/2013; · 1.59 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Although SPG11 is the most common complicated hereditary spastic paraplegia, our knowledge of the long-term prognosis and life expectancy is limited. We therefore studied the disease course of all patients with a proven SPG11 mutation as tested in our laboratory, the single Dutch laboratory providing SPG11 mutation analysis, between 1 January 2009 and 1 January 2011. We identified nine different SPG11 mutations, four of which are novel, in nine index patients. Eighteen SPG11 patients from these nine families were studied by means of a retrospective chart analysis and additional interview/examination. Ages at onset were between 4 months and 14 years; 39% started with learning difficulties rather than gait impairment. Brain magnetic resonance imaging showed a thin corpus callosum and typical periventricular white matter changes in the frontal horn region (known as the 'ears-of the lynx'-sign) in all. Most patients became wheelchair bound after a disease duration of 1 to 2 decades. End-stage disease consisted of loss of spontaneous speech, severe dysphagia, spastic tetraplegia with peripheral nerve involvement and contractures. Several patients died of complications between ages 30 and 48 years, 3-4 decades after onset of gait impairment. Other relevant features during the disease were urinary and fecal incontinence, obesity and psychosis. Our study of 18 Dutch SPG11-patients shows the potential serious long-term consequences of SPG11 including a possibly restricted life span.European Journal of Human Genetics advance online publication, 27 February 2013; doi:10.1038/ejhg.2013.27.
    European journal of human genetics: EJHG 02/2013; · 3.56 Impact Factor

Full-text (2 Sources)

Available from
May 27, 2014