Abstract
The autosomal recessive neuromuscular disorder proximal spinal muscular atrophy (SMA) is caused by the loss or mutation of the survival motor neuron (SMN) gene, which exists in two nearly identical copies, telomeric SMN (telSMN) and centromeric SMN (cenSMN). Exon 7 of the telSMN gene is homozygously absent in approximately 95% of SMA patients, whereas loss of cenSMN does not cause SMA. We searched for other telSMN mutations among 23 SMA compound heterozygotes, using heteroduplex analysis. We identified telSMN mutations in 11 of these unrelated SMA-like individuals who carry a single copy of telSMN: these include two frameshift mutations (800ins11 and 542delGT) and three missense mutations (A2G, S262I, and T274I). The telSMN mutations identified to date cluster at the 3' end, in a region containing sites for SMN oligomerization and binding of Sm proteins. Interestingly, the novel A2G missense mutation occurs outside this conserved carboxy-terminal domain, closely upstream of an SIP1 (SMN-interacting protein 1) binding site. In three patients, the A2G mutation was found to be on the same allele as a rare polymorphism in the 5' UTR, providing evidence for a founder chromosome; Ag1-CA marker data also support evidence of an ancestral origin for the 800ins11 and 542delGT mutations. We note that telSMN missense mutations are associated with milder disease in our patients and that the severe type I SMA phenotype caused by frameshift mutations can be ameliorated by an increase in cenSMN gene copy number.
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- Brahe C., Clermont O., Zappata S., Tiziano F., Melki J., Neri G. Frameshift mutation in the survival motor neuron gene in a severe case of SMA type I. Hum Mol Genet. 1996 Dec;5(12):1971–1976. doi: 10.1093/hmg/5.12.1971. [DOI] [PubMed] [Google Scholar]
- Brahe C., Velonà I., van der Steege G., Zappata S., van de Veen A. Y., Osinga J., Tops C. M., Fodde R., Khan P. M., Buys C. H. Mapping of two new markers within the smallest interval harboring the spinal muscular atrophy locus by family and radiation hybrid analysis. Hum Genet. 1994 May;93(5):494–501. doi: 10.1007/BF00202811. [DOI] [PubMed] [Google Scholar]
- Brzustowicz L. M., Lehner T., Castilla L. H., Penchaszadeh G. K., Wilhelmsen K. C., Daniels R., Davies K. E., Leppert M., Ziter F., Wood D. Genetic mapping of chronic childhood-onset spinal muscular atrophy to chromosome 5q11.2-13.3. Nature. 1990 Apr 5;344(6266):540–541. doi: 10.1038/344540a0. [DOI] [PubMed] [Google Scholar]
- Burghes A. H., Ingraham S. E., Kóte-Jarai Z., Rosenfeld S., Herta N., Nadkarni N., DiDonato C. J., Carpten J., Hurko O., Florence J. Linkage mapping of the spinal muscular atrophy gene. Hum Genet. 1994 Mar;93(3):305–312. doi: 10.1007/BF00212028. [DOI] [PubMed] [Google Scholar]
- Burghes A. H., Ingraham S. E., McLean M., Thompson T. G., McPherson J. D., Kote-Jarai Z., Carpten J. D., DiDonato C. J., Ikeda J. E., Surh L. A multicopy dinucleotide marker that maps close to the spinal muscular atrophy gene. Genomics. 1994 May 15;21(2):394–402. doi: 10.1006/geno.1994.1282. [DOI] [PubMed] [Google Scholar]
- Burghes A. H. When is a deletion not a deletion? When it is converted. Am J Hum Genet. 1997 Jul;61(1):9–15. doi: 10.1086/513913. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bussaglia E., Clermont O., Tizzano E., Lefebvre S., Bürglen L., Cruaud C., Urtizberea J. A., Colomer J., Munnich A., Baiget M. A frame-shift deletion in the survival motor neuron gene in Spanish spinal muscular atrophy patients. Nat Genet. 1995 Nov;11(3):335–337. doi: 10.1038/ng1195-335. [DOI] [PubMed] [Google Scholar]
- Bürglen L., Lefebvre S., Clermont O., Burlet P., Viollet L., Cruaud C., Munnich A., Melki J. Structure and organization of the human survival motor neurone (SMN) gene. Genomics. 1996 Mar 15;32(3):479–482. doi: 10.1006/geno.1996.0147. [DOI] [PubMed] [Google Scholar]
- Bürglen L., Seroz T., Miniou P., Lefebvre S., Burlet P., Munnich A., Pequignot E. V., Egly J. M., Melki J. The gene encoding p44, a subunit of the transcription factor TFIIH, is involved in large-scale deletions associated with Werdnig-Hoffmann disease. Am J Hum Genet. 1997 Jan;60(1):72–79. [PMC free article] [PubMed] [Google Scholar]
- Campbell L., Potter A., Ignatius J., Dubowitz V., Davies K. Genomic variation and gene conversion in spinal muscular atrophy: implications for disease process and clinical phenotype. Am J Hum Genet. 1997 Jul;61(1):40–50. doi: 10.1086/513886. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Carpten J. D., DiDonato C. J., Ingraham S. E., Wagner-McPherson C., Nieuwenhuijsen B. W., Wasmuth J. J., Burghes A. H. A YAC contig of the region containing the spinal muscular atrophy gene (SMA): identification of an unstable region. Genomics. 1994 Nov 15;24(2):351–356. doi: 10.1006/geno.1994.1626. [DOI] [PubMed] [Google Scholar]
- Carter T. A., Bönnemann C. G., Wang C. H., Obici S., Parano E., De Fatima Bonaldo M., Ross B. M., Penchaszadeh G. K., Mackenzie A., Soares M. B. A multicopy transcription-repair gene, BTF2p44, maps to the SMA region and demonstrates SMA associated deletions. Hum Mol Genet. 1997 Feb;6(2):229–236. doi: 10.1093/hmg/6.2.229. [DOI] [PubMed] [Google Scholar]
- Chakrabartty A., Schellman J. A., Baldwin R. L. Large differences in the helix propensities of alanine and glycine. Nature. 1991 Jun 13;351(6327):586–588. doi: 10.1038/351586a0. [DOI] [PubMed] [Google Scholar]
- Cobben J. M., van der Steege G., Grootscholten P., de Visser M., Scheffer H., Buys C. H. Deletions of the survival motor neuron gene in unaffected siblings of patients with spinal muscular atrophy. Am J Hum Genet. 1995 Oct;57(4):805–808. [PMC free article] [PubMed] [Google Scholar]
- Coovert D. D., Le T. T., McAndrew P. E., Strasswimmer J., Crawford T. O., Mendell J. R., Coulson S. E., Androphy E. J., Prior T. W., Burghes A. H. The survival motor neuron protein in spinal muscular atrophy. Hum Mol Genet. 1997 Aug;6(8):1205–1214. doi: 10.1093/hmg/6.8.1205. [DOI] [PubMed] [Google Scholar]
- Daniels R. J., Thomas N. H., MacKinnon R. N., Lehner T., Ott J., Flint T. J., Dubowitz V., Ignatius J., Donner M., Zerres K. Linkage analysis of spinal muscular atrophy. Genomics. 1992 Feb;12(2):335–339. doi: 10.1016/0888-7543(92)90382-3. [DOI] [PubMed] [Google Scholar]
- DiDonato C. J., Ingraham S. E., Mendell J. R., Prior T. W., Lenard S., Moxley R. T., 3rd, Florence J., Burghes A. H. Deletion and conversion in spinal muscular atrophy patients: is there a relationship to severity? Ann Neurol. 1997 Feb;41(2):230–237. doi: 10.1002/ana.410410214. [DOI] [PubMed] [Google Scholar]
- DiDonato C. J., Morgan K., Carpten J. D., Fuerst P., Ingraham S. E., Prescott G., McPherson J. D., Wirth B., Zerres K., Hurko O. Association between Ag1-CA alleles and severity of autosomal recessive proximal spinal muscular atrophy. Am J Hum Genet. 1994 Dec;55(6):1218–1229. [PMC free article] [PubMed] [Google Scholar]
- Fischer U., Liu Q., Dreyfuss G. The SMN-SIP1 complex has an essential role in spliceosomal snRNP biogenesis. Cell. 1997 Sep 19;90(6):1023–1029. doi: 10.1016/s0092-8674(00)80368-2. [DOI] [PubMed] [Google Scholar]
- Francis M. J., Morrison K. E., Campbell L., Grewal P. K., Christodoulou Z., Daniels R. J., Monaco A. P., Frischauf A. M., McPherson J., Wasmuth J. A contig of non-chimaeric YACs containing the spinal muscular atrophy gene in 5q13. Hum Mol Genet. 1993 Aug;2(8):1161–1167. doi: 10.1093/hmg/2.8.1161. [DOI] [PubMed] [Google Scholar]
- Gennarelli M., Lucarelli M., Capon F., Pizzuti A., Merlini L., Angelini C., Novelli G., Dallapiccola B. Survival motor neuron gene transcript analysis in muscles from spinal muscular atrophy patients. Biochem Biophys Res Commun. 1995 Aug 4;213(1):342–348. doi: 10.1006/bbrc.1995.2135. [DOI] [PubMed] [Google Scholar]
- Hahnen E., Forkert R., Marke C., Rudnik-Schöneborn S., Schönling J., Zerres K., Wirth B. Molecular analysis of candidate genes on chromosome 5q13 in autosomal recessive spinal muscular atrophy: evidence of homozygous deletions of the SMN gene in unaffected individuals. Hum Mol Genet. 1995 Oct;4(10):1927–1933. doi: 10.1093/hmg/4.10.1927. [DOI] [PubMed] [Google Scholar]
- Hahnen E., Schönling J., Rudnik-Schöneborn S., Raschke H., Zerres K., Wirth B. Missense mutations in exon 6 of the survival motor neuron gene in patients with spinal muscular atrophy (SMA). Hum Mol Genet. 1997 May;6(5):821–825. doi: 10.1093/hmg/6.5.821. [DOI] [PubMed] [Google Scholar]
- Hahnen E., Schönling J., Rudnik-Schöneborn S., Zerres K., Wirth B. Hybrid survival motor neuron genes in patients with autosomal recessive spinal muscular atrophy: new insights into molecular mechanisms responsible for the disease. Am J Hum Genet. 1996 Nov;59(5):1057–1065. [PMC free article] [PubMed] [Google Scholar]
- Jolly D. J., Okayama H., Berg P., Esty A. C., Filpula D., Bohlen P., Johnson G. G., Shively J. E., Hunkapillar T., Friedmann T. Isolation and characterization of a full-length expressible cDNA for human hypoxanthine phosphoribosyl transferase. Proc Natl Acad Sci U S A. 1983 Jan;80(2):477–481. doi: 10.1073/pnas.80.2.477. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kleyn P. W., Wang C. H., Lien L. L., Vitale E., Pan J., Ross B. M., Grunn A., Palmer D. A., Warburton D., Brzustowicz L. M. Construction of a yeast artificial chromosome contig spanning the spinal muscular atrophy disease gene region. Proc Natl Acad Sci U S A. 1993 Jul 15;90(14):6801–6805. doi: 10.1073/pnas.90.14.6801. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Lefebvre S., Burlet P., Liu Q., Bertrandy S., Clermont O., Munnich A., Dreyfuss G., Melki J. Correlation between severity and SMN protein level in spinal muscular atrophy. Nat Genet. 1997 Jul;16(3):265–269. doi: 10.1038/ng0797-265. [DOI] [PubMed] [Google Scholar]
- Lefebvre S., Bürglen L., Reboullet S., Clermont O., Burlet P., Viollet L., Benichou B., Cruaud C., Millasseau P., Zeviani M. Identification and characterization of a spinal muscular atrophy-determining gene. Cell. 1995 Jan 13;80(1):155–165. doi: 10.1016/0092-8674(95)90460-3. [DOI] [PubMed] [Google Scholar]
- Liu Q., Dreyfuss G. A novel nuclear structure containing the survival of motor neurons protein. EMBO J. 1996 Jul 15;15(14):3555–3565. [PMC free article] [PubMed] [Google Scholar]
- Liu Q., Fischer U., Wang F., Dreyfuss G. The spinal muscular atrophy disease gene product, SMN, and its associated protein SIP1 are in a complex with spliceosomal snRNP proteins. Cell. 1997 Sep 19;90(6):1013–1021. doi: 10.1016/s0092-8674(00)80367-0. [DOI] [PubMed] [Google Scholar]
- Lorson C. L., Androphy E. J. The domain encoded by exon 2 of the survival motor neuron protein mediates nucleic acid binding. Hum Mol Genet. 1998 Aug;7(8):1269–1275. doi: 10.1093/hmg/7.8.1269. [DOI] [PubMed] [Google Scholar]
- Lorson C. L., Strasswimmer J., Yao J. M., Baleja J. D., Hahnen E., Wirth B., Le T., Burghes A. H., Androphy E. J. SMN oligomerization defect correlates with spinal muscular atrophy severity. Nat Genet. 1998 May;19(1):63–66. doi: 10.1038/ng0598-63. [DOI] [PubMed] [Google Scholar]
- Lyu P. C., Liff M. I., Marky L. A., Kallenbach N. R. Side chain contributions to the stability of alpha-helical structure in peptides. Science. 1990 Nov 2;250(4981):669–673. doi: 10.1126/science.2237416. [DOI] [PubMed] [Google Scholar]
- MacKenzie A., Roy N., Besner A., Mettler G., Jacob P., Korneluk R., Surh L. Genetic linkage analysis of Canadian spinal muscular atrophy kindreds using flanking microsatellite 5q13 polymorphisms. Hum Genet. 1993 Jan;90(5):501–504. doi: 10.1007/BF00217448. [DOI] [PubMed] [Google Scholar]
- Mattaj I. W. Ribonucleoprotein assembly: clues from spinal muscular atrophy. Curr Biol. 1998 Jan 29;8(3):R93–R95. doi: 10.1016/s0960-9822(98)70055-7. [DOI] [PubMed] [Google Scholar]
- McAndrew P. E., Parsons D. W., Simard L. R., Rochette C., Ray P. N., Mendell J. R., Prior T. W., Burghes A. H. Identification of proximal spinal muscular atrophy carriers and patients by analysis of SMNT and SMNC gene copy number. Am J Hum Genet. 1997 Jun;60(6):1411–1422. doi: 10.1086/515465. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Melki J., Abdelhak S., Sheth P., Bachelot M. F., Burlet P., Marcadet A., Aicardi J., Barois A., Carriere J. P., Fardeau M. Gene for chronic proximal spinal muscular atrophies maps to chromosome 5q. Nature. 1990 Apr 19;344(6268):767–768. doi: 10.1038/344767a0. [DOI] [PubMed] [Google Scholar]
- Melki J., Lefebvre S., Burglen L., Burlet P., Clermont O., Millasseau P., Reboullet S., Bénichou B., Zeviani M., Le Paslier D. De novo and inherited deletions of the 5q13 region in spinal muscular atrophies. Science. 1994 Jun 3;264(5164):1474–1477. doi: 10.1126/science.7910982. [DOI] [PubMed] [Google Scholar]
- Miller S. A., Dykes D. D., Polesky H. F. A simple salting out procedure for extracting DNA from human nucleated cells. Nucleic Acids Res. 1988 Feb 11;16(3):1215–1215. doi: 10.1093/nar/16.3.1215. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Munsat T. L., Davies K. E. International SMA consortium meeting. (26-28 June 1992, Bonn, Germany). Neuromuscul Disord. 1992;2(5-6):423–428. doi: 10.1016/s0960-8966(06)80015-5. [DOI] [PubMed] [Google Scholar]
- Parsons D. W., McAndrew P. E., Allinson P. S., Parker W. D., Jr, Burghes A. H., Prior T. W. Diagnosis of spinal muscular atrophy in an SMN non-deletion patient using a quantitative PCR screen and mutation analysis. J Med Genet. 1998 Aug;35(8):674–676. doi: 10.1136/jmg.35.8.674. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Parsons D. W., McAndrew P. E., Monani U. R., Mendell J. R., Burghes A. H., Prior T. W. An 11 base pair duplication in exon 6 of the SMN gene produces a type I spinal muscular atrophy (SMA) phenotype: further evidence for SMN as the primary SMA-determining gene. Hum Mol Genet. 1996 Nov;5(11):1727–1732. doi: 10.1093/hmg/5.11.1727. [DOI] [PubMed] [Google Scholar]
- Pearn J. Classification of spinal muscular atrophies. Lancet. 1980 Apr 26;1(8174):919–922. doi: 10.1016/s0140-6736(80)90847-8. [DOI] [PubMed] [Google Scholar]
- Rochette C. F., Surh L. C., Ray P. N., McAndrew P. E., Prior T. W., Burghes A. H., Vanasse M., Simard L. R. Molecular diagnosis of non-deletion SMA patients using quantitative PCR of SMN exon 7. Neurogenetics. 1997 Sep;1(2):141–147. doi: 10.1007/s100480050021. [DOI] [PubMed] [Google Scholar]
- Rodrigues N. R., Owen N., Talbot K., Ignatius J., Dubowitz V., Davies K. E. Deletions in the survival motor neuron gene on 5q13 in autosomal recessive spinal muscular atrophy. Hum Mol Genet. 1995 Apr;4(4):631–634. doi: 10.1093/hmg/4.4.631. [DOI] [PubMed] [Google Scholar]
- Roy N., Mahadevan M. S., McLean M., Shutler G., Yaraghi Z., Farahani R., Baird S., Besner-Johnston A., Lefebvre C., Kang X. The gene for neuronal apoptosis inhibitory protein is partially deleted in individuals with spinal muscular atrophy. Cell. 1995 Jan 13;80(1):167–178. doi: 10.1016/0092-8674(95)90461-1. [DOI] [PubMed] [Google Scholar]
- Simard L. R., Rochette C., Semionov A., Morgan K., Vanasse M. SMN(T) and NAIP mutations in Canadian families with spinal muscular atrophy (SMA): genotype/phenotype correlations with disease severity. Am J Med Genet. 1997 Oct 3;72(1):51–58. doi: 10.1002/(sici)1096-8628(19971003)72:1<51::aid-ajmg11>3.0.co;2-t. [DOI] [PubMed] [Google Scholar]
- Simard L. R., Vanasse M., Rochette C., Morgan K., Lemieux B., Melançon S. B., Labuda D. Linkage study of chronic childhood-onset spinal muscular atrophy (SMA): confirmation of close linkage to D5S39 in French Canadian families. Genomics. 1992 Sep;14(1):188–190. doi: 10.1016/s0888-7543(05)80305-2. [DOI] [PubMed] [Google Scholar]
- Talbot K., Ponting C. P., Theodosiou A. M., Rodrigues N. R., Surtees R., Mountford R., Davies K. E. Missense mutation clustering in the survival motor neuron gene: a role for a conserved tyrosine and glycine rich region of the protein in RNA metabolism? Hum Mol Genet. 1997 Mar;6(3):497–500. doi: 10.1093/hmg/6.3.497. [DOI] [PubMed] [Google Scholar]
- Thompson T. G., DiDonato C. J., Simard L. R., Ingraham S. E., Burghes A. H., Crawford T. O., Rochette C., Mendell J. R., Wasmuth J. J. A novel cDNA detects homozygous microdeletions in greater than 50% of type I spinal muscular atrophy patients. Nat Genet. 1995 Jan;9(1):56–62. doi: 10.1038/ng0195-56. [DOI] [PubMed] [Google Scholar]
- Velasco E., Valero C., Valero A., Moreno F., Hernández-Chico C. Molecular analysis of the SMN and NAIP genes in Spanish spinal muscular atrophy (SMA) families and correlation between number of copies of cBCD541 and SMA phenotype. Hum Mol Genet. 1996 Feb;5(2):257–263. doi: 10.1093/hmg/5.2.257. [DOI] [PubMed] [Google Scholar]
- Wirth B., Pick E., Leutner A., Dadze A., Voosen B., Knapp M., Piechaczek-Wappenschmidt B., Rudnik-Schöneborn S., Schönling J., Cox S. Large linkage analysis in 100 families with autosomal recessive spinal muscular atrophy (SMA) and 11 CEPH families using 15 polymorphic loci in the region 5q11.2-q13.3. Genomics. 1994 Mar 1;20(1):84–93. doi: 10.1006/geno.1994.1130. [DOI] [PubMed] [Google Scholar]
- Wirth B., el-Agwany A., Baasner A., Burghes A., Koch A., Dadze A., Piechaczeck-Wappenschmidt B., Rudnik-Schöneborn S., Zerres K., Schönling J. Mapping of the spinal muscular atrophy (SMA) gene to a 750-kb interval flanked by two new microsatellites. Eur J Hum Genet. 1995;3(1):56–60. doi: 10.1159/000472274. [DOI] [PubMed] [Google Scholar]
- van der Steege G., Grootscholten P. M., Cobben J. M., Zappata S., Scheffer H., den Dunnen J. T., van Ommen G. J., Brahe C., Buys C. H. Apparent gene conversions involving the SMN gene in the region of the spinal muscular atrophy locus on chromosome 5. Am J Hum Genet. 1996 Oct;59(4):834–838. [PMC free article] [PubMed] [Google Scholar]
- van der Steege G., Grootscholten P. M., van der Vlies P., Draaijers T. G., Osinga J., Cobben J. M., Scheffer H., Buys C. H. PCR-based DNA test to confirm clinical diagnosis of autosomal recessive spinal muscular atrophy. Lancet. 1995 Apr 15;345(8955):985–986. [PubMed] [Google Scholar]