Hereditary Spastic Paraplegia with Thin Corpus Callosum Reduction of the SPG11 Interval and Evidence for Further Genetic Heterogeneity

ORIGINAL CONTRIBUTION Hereditary Spastic Paraplegia With Thin Corpus Callosum Reduction of the SPG11 Interval and Evidence for Further Genetic Heterogeneity

Alexander Lossos, MD; Giovanni Stevanin, PhD; Vardiella Meiner, MD; Zohar Argov, MD; Naima Bouslam, MS; J. P. Newman, PhD; John M. Gomori, MD; Stephan Klebe, MD; Israela Lerer, MSc; Nizar Elleuch, MD; Shira Silverstein, MSc; Alexandra Durr, MD; Oded Abramsky, MD, PhD; Ziva Ben-Nariah, MD; Alexis Brice, MD

Background: Hereditary spastic paraplegia (HSP) Patients: Seven patients with HSP-TCC who belong to 3 with thin corpus callosum (TCC) is an autosomal reces- consanguineous families of Arab origin residing in Israel. sive form of complicated HSP mainly characterized by Results: The 7 patients manifested a relatively similar com- slowly progressive spastic paraparesis and mental dete- bination of adolescence-onset cognitive decline and spas- rioration beginning in the second decade of life. The tic paraparesis with TCC on brain magnetic resonance im- locus for HSP-TCC, designated SPG11, was mapped to aging. After excluding the SPG7 locus, we tested the 3 chromosome 15q13-15 in some of the affected families families for linkage to the SPG11, SPG21/MAST, and ACCPN from Japan, Europe, and North America, spanning an loci associated with autosomal recessive disorders with TCC. interval of 17.5 megabases (Mb). Two families showed evidence for linkage to SPG11 (Zmax=5.55) and reduced the candidate region to 13 Mb. Objective: To perform a clinical and genetic study of HSP-TCC. Conclusions: Our findings in HSP-TCC further confirm its worldwide distribution and genetic heterogeneity, and they significantly reduce the candidate SPG11 interval. Design and Setting: Case series; multi-institutional study. Arch Neurol. 2006;63:756-760

EREDITARY SPASTIC variability. Later studies defined a paraplegia (HSP) with thin 20-centimorgan interval in this region in 10 Author Affiliations: corpus callosum (TCC) of 13 Japanese families with HSP-TCC7 and Department of Neurology, (Online Mendelian Inher- in 5 of 12 Italian families with HSP-TCC,8 Agnes Ginges Center for itance in Man [OMIM] demonstrating genetic heterogeneity. We Human Neurogenetics #604360) is an autosomal recessive form of present the results of genetic analysis in 3 (Drs Lossos, Argov, Newman, H complicated HSP characterized clinically by Arab families from Israel with HSP-TCC. and Abramsky), and Departments of Human slowly progressive spastic paraparesis and Genetics (Drs Meiner and mental deterioration beginning in the sec- 1 METHODS Ben-Nariah and Mss Lerer and ond decade of life. Additional manifesta- Silverstein) and Radiology tions include urinary incontinence, sen- (Dr Gomori), Hadassah-Hebrew sory deficit in the legs, late distal We evaluated 7 patients with HSP-TCC who University Medical Center, amyotrophy, occasional seizures, extrapy- belong to 3 consanguineous families of Arab Jerusalem, Israel; and Institut ramidal signs, and cerebellar ataxia. Al- origin residing in Israel. Of the 31 living fam- National de la Sante´etdela though the appearance of TCC on cerebral ily members, 8 parents and 11 clinically unaf- Recherche Me´dicale Unit 679 magnetic resonance imaging is typical of fected siblings ranging in age from 15 to 35 (formerly Unit 289), Federative 1 years (mean age, 23 years) were also available Institute for Neuroscience HSP-TCC, it also occurs in some of the for the study. The study was approved by the Research (IFR70) other HSPs, including those related to Ethics Committee, Hadassah Medical Organi- 2 3 4 (Drs Stevanin, Klebe, Elleuch, SPG7, SPG21, and SPG4, and in periph- zation, Jerusalem, Israel. Durr, and Brice and eral neuropathy with agenesis of the cor- Diagnosis of HSP-TCC was established ac- Ms Bouslam), Department of pus callosum,5 making genetic analysis es- cording to the published criteria.6,7 Age at symp- Genetics, Cytogenetics, and sential for diagnosis. tom onset was obtained from the parents or the Embryology, AP-HP The locus for HSP-TCC, designated available medical records. Because of lan- (Drs Stevanin, Durr, and Brice), SPG11, was originally assigned to chromo- guage limitations, we used the Test of Non- Federation of Neurology, AP-HP verbal Intelligence9 for the assessment of men- (Dr Brice), and Pitie´-Salpeˆtrière some 15q13-15 overlapping the ACCPN tal status. This language-free test of visual Medical School, Pierre and locus in 7 families from Italy and North logical reasoning yields predicted IQ scores 6 Marie Curie University America. Onset in early childhood, nor- when other batteries cannot be applied. (Dr Brice), Salpeˆtrière Hospital, mal intelligence, and the absence of TCC High-molecular-weight DNA was ex- Paris, France. in some of these families suggested clinical tracted from peripheral blood samples of 26

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©2006 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/25/2021 Table. Clinical and Imaging Findings in 7 Patients With Hereditary Spastic Paraplegia With Thin Corpus Callosum

Family 670 Family 672 Family 671

Finding Patient 4 Patient 5 Patient 3 Patient 5 Patient 10 Patient 4 Patient 5 Sex/age at examination, y Female/31 Male/30 Male/27 Female/25 Female/23 Female/24 Female/23 Age at onset, y Cognitive decline 12 12 14 15 Ͻ10 20 20 Gait disturbance 17 17 16 17 13 18 19 Disability stage* 444 4332 Nonverbal IQ 61 69 78 75 65 78 77 Pseudobulbar dysarthria ϩϩϩ ϩϩϩϩ LL hyperreflexia ϩϩϩ ϩϩϩϩ LL spasticity ϩϩϩ ϩϩϩϩ UL hyperreflexia ϩϩϩ ϩϩϩϩ UL spasticity − − − − − − Rigidity Extensor plantar response ϩϩϩ ϩϩϩϩ Distal amyotrophy ϩϩϩ ϩϩϩϩ Urinary problems − − − − ϩϩ − Cerebral MRI Thin corpus callosum ND R, G, B, S R, G, B, S ND NA R, G, B, S R, G, B, S WMA ND F, O, Pv F, O, Pv ND NA F, O, Pv F, O, Pv Mild frontal atrophy ND ϩϩND NA ϩ − Peroneal nerve MNCV, m/s 47 43 49 ND 46 37 47 CMAP, mV 1.1 3.2 2.6 ND 4.1 3.0 4.5 Sural nerve SNCV, m/s 44 45 48 ND 48 36 46 SNAP, µV 4 5 10 ND 9 16 12

Abbreviations: B, body; CMAP, compound motor action potential amplitude; F, frontal; G, genu; LL, lower limb; MNCV, motor nerve conduction velocity; MRI, magnetic resonance imaging; NA, not available; ND, not done; O, occipital; Pv, periventricular; R, rostrum; S, splenium; SNAP, sensory nerve action potential amplitude; SNCV, sensory nerve conduction velocity; UL, upper limb; WMA, white matter abnormalities; ϩ, presence; −, absence. *Disability stage at last examination: 2 indicates moderate gait stiffness without consistent use of assistive device; 3, marked gait stiffness with consistent use of assistive device; and 4, wheelchair bound.

subjects. Coding exons of the SPG7 gene were screened by de- ciated with mild hand tremor, and patient 671-4 devel- naturing high-performance liquid chromatography, showing oped urinary incontinence late in the course of her disease. no abnormal profile in the affected representatives from each 7,8 Additional features included high-arched palate in pa- family. Twelve microsatellite markers covering the SPG11, tients 670-4, 670-5, and 671-4, obesity with a body mass SPG21/MAST,3 and ACCPN5 loci were selected for linkage analysis. Genotypes were determined using standard methods in an index above 33 (where BMI is the weight in kilograms di- ABI 3730 automated sequencer and the GeneMapper version vided by the height in meters squared) in patients 672-3 3.5 software (Applied Biosystems, Foster City, Calif). Linkage and 672-5, and wide interdental spaces and Raynaud phe- analysis was performed using Allegro software (deCODE Ge- nomenon in patient 671-4. netics, Reykjavik, Iceland) assuming a fully penetrant reces- Consistent with the clinical findings, all of the 4 pa- sive disease with a frequency of 0.00005, similar male-female tients studied by magnetic resonance imaging had TCC recombination frequencies, and equal allele frequencies. most prominent in the rostrum, genu, and body associated with confluent and symmetric signal hyperintensi- RESULTS ties on T2-weighted and fluid-attenuated inversion re- covery sequences in the cerebral white matter (Table). CLINICAL FINDINGS Widening of the anterior interhemispheric fissure was present in the 3 oldest patients, possibly the conse- Clinical findings at last examination are summarized in the quence of a mild frontal atrophy. Basal ganglia, brain- Table. All of the 7 patients manifested slowly progressive stem, cerebellum, and the cervical spinal cord appeared spastic paraparesis, distal hand and foot muscle atrophy and normal. Only brain computed tomography was avail- weakness, signs of pseudobulbar dysfunction, and pro- able in patient 671-10, and it showed TCC. Results of gressive mental impairment. The functional disability tended peripheral nerve conduction studies were consistent with to correlate with age. While no patients had sensory defi- borderline-to-mild predominantly axonal polyneuropa- cit, seizures, signs of cerebellar dysfunction, or cataracts, thy in patients 670-4, 670-5, and 671-4 and were nor- some clinical variability was apparent in family 671. Al- mal in patients 671-10 and 671-5. Sural nerve biopsy in though patient 671-10 initially had gait disturbance and patients 670-4 and 671-4 showed signs of axonal degen- urinary incontinence at age 13 years, she was reported to eration, and a quadricep muscle biopsy specimen in pa- have mild mental retardation since early childhood. Pa- tient 670-5 showed chronic neurogenic changes with- tient 671-5 had extrapyramidal rigidity in the hands asso- out specific alterations.

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cM ∗ ∗ D15S144 2 3 2 2 D15S1040 0.6 6 7 6 5 ACCPN 3.1 1 2 D15S971 4 6 4 2 (SLC12A6 Gene) D15S1044 8.3 1 3 ∗ ∗ ∗ ∗ ∗ 1 2 D15S780 4 3 3 4 5 6 7 4 4 D15S778 0 4 3 4 5 SPG11 D15S783 2 3 2 2 3 2 2 2 3 2 3 2 2 3 D15S182 1 3 6 5 7 6 6 6 7 5 7 6 1 2 D15S1508 5.3 1 1 4 2 6 4 4 4 6 2 6 4 1 1 D15S143 2 1 1 2 1 1 1 1 3 2 3 1 2 1 14.5 SPG21/MAST D15S108 3 10 4 4 4 4 4 4 3 4 3 4 8 5 0 (ACP33 Gene) D15S1507 8 7 4 5 4 4 4 4 3 5 3 4 10 8 2 3 2 2 2 2 3 3 3 2 1 2 1 1 1 1 3 2 3 1 1 1 1 1 1 1 1 1 1 1 2 1 2 2 2 2 1 1 1 2 3 5 3 8 3 5 10 8 3 8 8 8 8 10 8 8 7 10 8 10

cM ∗ ∗ D15S144 2 7 6 2 D15S1040 0.6 1 3 3 1 ACCPN 3.1 2 1 D15S971 6 2 4 1 (SLC12A6 Gene) D15S1044 8.3 3 3 ∗ ∗ ∗∗∗3 3 D15S780 4 6 3 4 567? 6 4 D15S778 0 3 6 6 3 SPG11 D15S783 1 2 2 2 7 6 2 2 2 2 2 6 3 1 D15S182 4 1 1 1 3 3 1 1 1 1 1 3 2 4 D15S1508 5.3 1 1 6 1 2 4 6 1 6 1 6 4 2 1 D15S143 4 1 3 3 3 3 3 3 3 3 3 3 2 3 SPG21/MAST D15S108 14.5 4 8 4 4 6 6 4 4 6 4 4 6 11 5 D15S1507 0 9 7 3 3 6 6 3 3 6 3 3 6 7 6 (ACP33 Gene) 1 1 2 3 1 1 2 1 1 3 4 4 1 2 4 4 1 4 4 2 1 1 1 2 1 1 - - 1 2 4 3 1 2 4 3 - - 4 2 4 5 8 11 4 5 8 5 4 11 9 6 7 7 9 6 7 6 9 7

∗∗∗ ∗ 892 1 ∗ ∗ ∗ ∗ ∗ ∗ ∗ ∗ 10 11 12 2 3 4 5 6 7

Figure 1. Pedigrees of families 670 (A), 672 (B), and 671 (C). Haplotype reconstruction for the 12 microsatellite markers positioned according to the human genome draft sequence (http://www.ncbi.nlm.nih.gov and http://www.ensembl.org) are shown in the 2 families, family 670 (A) and family 672 (B), linked to SPG11. The homo- zygous haplotype in which the mutated gene is presumed to be located is flanked in black. Filled symbols indicate family members affected with hereditary spastic paraplegia with thin corpus callosum; circles, women; squares, men; diamonds, sex unspecified; asterisks, available and studied individuals; arrows, the position of the SLC12A6 and ACP33 genes; and cM, centimorgan.

MOLECULAR ANALYSIS #218000), and SPG11. Linkage analyses generated nega- tive lod scores with markers flanking the ACP33/MAST Given the clinical presentation, we tested these families (D15S108, D15S1507) and SLC12A6/KCC3 (D15S1040, for linkage to the 3 loci on chromosome 15 that are as- D15S971) genes in accordance with haplotype recon- sociated with autosomal recessive disorders with TCC: structions (Figure 1 and Figure 2), excluding their in- SPG21/MAST (OMIM #248900), ACCPN (OMIM volvement in the disease. However, families 670 and 672

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©2006 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/25/2021 demonstrated positive lod scores for the 7 markers spanning the SPG11 candidate interval with combined 6 pairwise lod scores greater than 3 at D15S778, 4 D15S783, and D15S182. A significant multipoint lod 2 score of 3.1 was obtained in this region in family 670 0 whereas it reached 2.5 for family 672. Haplotype –2 –4 reconstructions revealed the existence of a recombina- Lod Score –6 tion event between D15S971 and D15S1044 in family –8 670, setting the centromeric boundary to D15S971 –10 (Figure 1). The telomeric boundary was defined at –12 D15S143 because of the loss of homozygosity between 0.6 3.1 8.3 00005.3 14.5 0 this marker and D15S1508 in family 672. In contrast, CM linkages to SPG11 (Figure 2) and SPG4 (data not shown) were excluded in family 671. D15S971 D15S780 D15S143 D15S108 D15S1044 D15S778 D15S783 D15S182 D15S1507 D15S144 D15S1040

SLC12A6 (ACCPN) SPG11 ACP33 (SPG21) COMMENT Figure 2. Multipoint linkage analysis. Lod scores are plotted according to the genetic map of chromosome 15 (http://research.marshfieldclinic.org/genetics) To our knowledge, this is the first description of for the SG11-linked families 670 and 672 (solid line) and for the unlinked family HSP-TCC in patients of Arab origin. Originally de- 671 (dashed line). Arrows indicate the position of the SLC12A6 and ACP33 scribed in Japan,1 HSP-TCC apparently shows a world- genes; cM, centimorgan. wide distribution and probably represents a common form of autosomal recessive HSP.6-8 Our patients share simi- SPG11-unlinked families. Furthermore, parkinsonism lar clinical and imaging manifestations with those de- was previously described in a South Korean family with scribed in other populations, and they add minor oro- HSP-TCC.11 dental dysmorphism to the list of associated abnormalities. In conclusion, our findings in HSP-TCC in Israel fur- In addition, although Raynaud phenomenon in one of ther confirm its worldwide distribution and genetic het- our patients may be coincidental, obesity was also no- erogeneity, and they significantly reduce the candidate ticed in a family from Germany linked to SPG11.10 SPG11 interval. We found no mutations in the coding sequence of the SPG7 gene or linkage to the SPG21/MAST or ACCPN loci Accepted for Publication: November 22, 2005. in the 3 families, which supports the previous conclu- Correspondence: Alexander Lossos, MD, Department of sion that peripheral neuropathy with agenesis of the cor- Neurology, Hadassah University Hospital, PO Box 12000, pus callosum and SPG11 are not allelic disorders.10 How- Jerusalem 91120, Israel ([email protected]). ever, 2 of our 3 families demonstrated significant linkage Author Contributions: Study concept and design: Lossos, to the SPG11 locus. Haplotype reconstruction in these Stevanin, Meiner, Durr, and Brice. Acquisition of data: families allows for the reduction of the candidate inter- Lossos, Stevanin, Meiner, Argov, Bouslam, Newman, val from 17.5 megabases (Mb) (approximately 25 cen- Gomori, Lerer, Elleuch, Silverstein, and Ben-Nariah. timorgans)7,8 to 13 Mb (approximately 17 centimor- Analysis and interpretation of data: Lossos, Stevanin, gans) flanked by markers D15S971 and D15S143. This Meiner, Argov, Bouslam, Newman, Gomori, Klebe, Lerer, region contains more than 120 known genes. The ex- Elleuch, Silverstein, Durr, Abramsky, Ben-Nariah, and clusion of linkage to SPG11 in the third family further Brice. Drafting of the manuscript: Lossos, Stevanin, Meiner, demonstrates genetic heterogeneity in this disorder.7,8 Klebe, and Brice. Critical revision of the manuscript for im- Retrospective analysis of the clinical phenotype in portant intellectual content: Lossos, Stevanin, Meiner, light of these results reveals relatively similar neurologi- Argov, Bouslam, Newman, Gomori, Lerer, Elleuch, cal and imaging findings in the SPG11-linked and Silverstein, Durr, Abramsky, Ben-Nariah, and Brice. Sta- SPG11-unlinked families, suggesting that responsible tistical analysis: Stevanin. Obtained funding: Lossos, genes may be functionally related. Still, there are a few Stevanin, and Brice. Administrative, technical, and mate- subtle differences. Whereas patients from the 2 linked rial support: Lossos, Stevanin, Meiner, Argov, Klebe, Lerer, families initially had cognitive decline and later devel- and Abramsky. Study supervision: Lossos, Stevanin, oped a highly homogeneous combination of motor defi- Meiner, Argov, Durr, Abramsky, and Brice. cit and mental impairment, patients from the unlinked Funding/Support: This work was supported in part by family somewhat differed in the early manifestations as the Hadassah International France (Dr Lossos), the well as in the range of additional features. Two of the GIS-Institute for Rare Diseases (Drs Stevanin and Durr), patients had gait disturbance, 1 was reported to have the Verum Foundation (Dr Brice), and the French mild mental retardation since early childhood, 1 had National Institute for Health and Medical Research. Ms extrapyramidal signs, and 2 showed no electrophysi- Bouslan and Dr Elleuch received fellowship from the ologic evidence of peripheral neuropathy. Because each French Association Against Friedreich Ataxia and from of these features and some variability between the the Association Connaitre les Syndrome Cerebelleux, re- affected siblings may be present in SPG11,6,8 these find- spectively. Dr Klebe was supported by the postdoctoral ings probably do not have discriminative clinical value program of the German Academic Exchange Service and and cannot distinguish our SPG11-linked and by the Verum Foundation.

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©2006 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/25/2021 Acknowledgment: We are grateful to Sylvie Forlani, PhD, KCC3 cause a severe peripheral neuropathy associated with agenesis of the cor- and Hamid Azzedine, PhD, for their help. pus callosum. Nat Genet. 2002;32:384-392. 6. Martinez Murillo F, Kobayashi H, Pegoraro E, et al. Genetic localization of a new locus for recessive familial spastic paraparesis to 15q13-15. Neurology. 1999; REFERENCES 53:50-56. 7. Shibasaki Y, Tanaka H, Iwabuchi K, et al. Linkage of autosomal recessive he- 1. Ueda M, Katayama Y, Kamiya T, et al. Hereditary spastic paraplegia with a thin reditary spastic paraplegia with mental impairment and thin corpus callosum to corpus callosum and thalamic involvement in Japan. Neurology. 1998;51:1751- chromosome 15q13-15. Ann Neurol. 2000;48:108-112. 1754. 8. Casali C, Valente EM, Bertini E, et al. Clinical and genetic studies in hereditary 2. Coutinho P, Barros J, Zemmouri R, et al. Clinical heterogeneity of autosomal re- spastic paraplegia with thin corpus callosum. Neurology. 2004;62:262-268. cessive spastic paraplegias: analysis of 106 patients in 46 families. Arch Neurol. 9. Brown L, Sherbenou RJ, Johnsen SK. Test of Nonverbal Intelligence. 2nd ed. 1999;56:943-949. Austin, Tex: Pro-Ed; 1990. 3. Simpson MA, Cross H, Proukakis C, et al. Maspardin is mutated in Mast syn- 10. Winner B, Uyanik G, Gross C, et al. Clinical progression and genetic analysis in drome, a complicated form of hereditary spastic paraplegia associated with hereditary spastic paraplegia with thin corpus callosum in spastic gait gene 11 dementia. Am J Hum Genet. 2003;73:1147-1156. (SPG11). Arch Neurol. 2004;61:117-121. 4. Orlacchio A, Kawarai T, Totaro A, et al. Hereditary spastic paraplegia: clinical ge- 11. Kang SY, Lee MH, Lee SK, Sohn YH. Levodopa-responsive parkinsonism in he- netic study of 15 families. Arch Neurol. 2004;61:849-855. reditary spastic paraplegia with thin corpus callosum. Parkinsonism Relat Disord. 5. Howard HC, Mount DB, Rochefort D, et al. Mutations in the K-Cl cotransporter 2004;10:425-427.

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