TABLES

Reference ranges for oligonucleotide repeat sizes at the main SCA loci

(modifed from Table 3 of Sequeiros J, Seneca S and Martindale J: Consensus and controversies in best practices for
molecular genetic testing of the spinocerebellar ataxias. Eur J Hum Genet 18:1173-6, 2010)

ATAXIA REPEAT NORMAL URCERTAIN2 REDUCED PENETRANCE FULL PENETRANCE REFERENCES1
SCA1 (CAG)n (CAT)n (CAG)n 3 6-38;
39-44 CAT interrupted		 -4 - 39-44 CAGs uninterrupted;
45-91		 (Orr et al, 1993; Quan et al, 1995; Goldfarb et al, 1996; Zühlke et al, 2002)
DRPLA (CAG)n 6-35 - - 49-93 (Koide et al, 1994; Nagafuchi et al, 1994; Shimojo et al, 2001)
SCA2 [ (CAG)n CAA (CAG)n ]n 5 14-31 32-34 6 - 35-500 (Imbert et al, 1996; Pulst et al, 1996; Sanpei et al, 1996; Cancel et al, 1997; Leggo et al, 1997; Costanzi-Porrini et al, 2000; Fernandez et al, 2000; Choudhry et al, 2001; Silveira et al, 2002; Mao et al, 2002; Kim et al, 2007)
MJD/SCA3 (CAG)2 CAA AAG CAG CAA (CAG)n 11-44 45-59 7 - 61-87 (Maciel et al, 1995; Takiyama et al, 1997; van Schaik et al, 1997; Egan et al, 2000; Maciel et al, 2001; van Alfen et al, 2001; Padiath et al, 2005; Gu et al, 2004)
SCA6 (CAG)n 4-18 - 19 20-33 (Ishikawa et al, 1997; Zhuchenko et al, 1997; Stevanin et al,1997; Shizuka et al,1998, Yabe et al,1998; Katayama et al,2000; Mariotti et al, 2001; Takahashi et al, 2004)
SCA7 (CAG)n 4-19 28-33 34-35 36-460 (David et al, 1997; Stevanin et al, 1998; Koob et al, 1998; Benton et al, 1998; Johannson et al, 1998; Giunti et al, 1999; Nardacchione et al, 1999; Van de Warrenburg et al, 2001; Ansorge et al, 2004; Whitney et al, 2007)
SCA8 (CAG/TAG)n 14-42 - 8 ≥74-1,000 8 - 8 (Koob et al, 1999; Silveira et al, 2000; Cellini et al, 2001; Ikeda et al, 2004; Sulek et al, 2004)
SCA10 (ATTCT)n 9 8-32 280 >280-850 850-4,500 (Matsuura et al, 2000; Alonso et al, 2006; Matsuura et al, 2006; Wang et al, 2008; Raskin et al, 2007)
SCA12 (CAG)n 4-32 10 40-45 10 - 51-78 10 (Holmes et al, 1999; Fujigasaki et al, 2001; Holmes et al, 2003; Hellenbroich et al, 2004; Bahl et al, 2005)
SCA17 [ (CAG)n (CAA)n (CAG)n ]n 25-42 - 43-48 49-66 (Zühlke et al, 2003; Oda et al, 2004, Mariotti et al, 2007; Zühlke and Bürk, 2007; Stevanin and Brice, 2008)

1 Full references are available at: http://www.scabase.eu
2 "Uncertain" range was defined whenever there was only one, or two or more contradictory reports.
3 May be interrupted by 1 to 3, or exceptionally 4, CATs.
4 One report of non-penetrance with a 44 repeat allele, but not described as pure or interrupted (Goldfarb et al, 1996).
5 The CAG repeat may be pure or have 1 to 4 CAA interruptions.
6 An interrupted 32 repeat allele found in a patient (Silveira et al, 2002); an uninterrupted 32 CAGs allele in a (young) asymptomatic person (Cancel et al, 1997); a 33 pure CAG repeat in one patient (Fernandez et al, 2000); a 34 interrupted repeat in one patient (Constanzi-Porrini et al, 2000); 32, 34 and 35 interrupted repeats found in patients with Parkinsonism (Kim et al, 2007).
7 A 45 CAG allele in one patient (Padiath et al, 2005); one family segregating a 51 CAG allele, apparently not associated with the disease (Maciel et al, 2001); a 51 allele in one patient from a MJD family (Gu et al, 2004); one family segregating 53 and 54 alleles associated with an 'abnormal phenotype' (van Alfen et al, 2001); a 54 CAGs allele in a patient from a MJD family (van Schaik et al, 1997); a 55 allele described in one patient (Egan et al, 2000); a 56 allele described in one patient (Takiyama et al, 1997);
8 Pathogenic ranges and incomplete penetrance are very uncertain in SCA8; there is a large overlap of repeat sizes in patients and in persons with no symptoms and no family history of ataxia, but it may depend on the family; however, expansions were also present in 0.4% of controls (Ikeda et al, 2004); Silveira et al (2000) had reported before different ranges, seeing no overlap in controls (15-91) and pathogenic (100-152 repeat) alleles; however, they found a very high instability in sperm (contractions and expansions), both for expanded and normal alleles; patients were found with schizophrenia or bipolar disorder, depression, or borderline personality disorder with 1140 and 1300 repeats (Vincent et al, 2000).
9 Interruptions with multiple penta or septarepeats or complex ATTGT-TTTCT repeats are found both in normal alleles with ≥17 repeats, and in pathogenic alleles (Matsuura et al, 2006; Hagerman et al, 2009).
10 Alleles with 40 and 41 repeats, in two patients, were included in a review by Hellenbroich et al (2004); a 45 repeat allele was seen in a normal Indian control sample of an individual, without neurological or psychiatric signs or symptoms and with no known family history (Fujigasaki et al. 2001); an asymptomatic homozygote for expanded alleles (52 and 59 repeats) was reported by Bahl et al. (2005); an Iranian woman with unipolar depression and her MZ twin sons with schizophrenia all had a 53-CAG repeat (Holmes et al., 2002).