Alternative titles; symbols
SNOMEDCT: 1003395004;
Cytogenetic location: 7p13-q32 Genomic coordinates (GRCh38) : 7:43,300,001-132,900,000
| Location | Phenotype |
Phenotype MIM number |
Inheritance |
Phenotype mapping key |
|---|---|---|---|---|
| 7p13-q32 | Silver-Russell syndrome 2 | 618905 | Autosomal dominant | 4 |
A number sign (#) is used with this entry because Silver-Russell syndrome-2 (SRS2) is an imprinting disorder involving genes within the imprinted region of chromosome 7.
Silver-Russell syndrome-2 (SRS2) is characterized by pre- and postnatal growth retardation, with relative sparing of cranial growth, triangular facies, and downturned corners of the mouth. Fifth-finger clinodactyly and facial, limb, or truncal asymmetry are also frequently present (summary by Monk et al., 2000).
For a discussion of genetic heterogeneity of Silver-Russell syndrome, see SRS1 (180860).
Eggerding et al. (1994) reported a female child with growth retardation in whom the normal chromosome 7 homologs were replaced by isochromosomes of 7p and 7q. Molecular studies showed that the child had paternal 7p isodisomy and maternal 7q isodisomy. Phenotypically, she had triangular facies, mild clinodactyly, and limb asymmetry. The authors suggested that imprinting may play a role.
Kotzot et al. (1995) described 3 patients who were diagnosed with SRS and were found to have maternal uniparental disomy for chromosome 7. Birth weight and length were below the third percentile for gestational age. All patients displayed the full spectrum of SRS features, including the characteristic facies. A fourth patient with chromosome 7 maternal disomy, who had been diagnosed with primordial growth retardation, showed SRS features of triangular face with broad forehead and prominent philtrum and lips, short fifth fingers with clinodactyly, excessive sweating over the forehead, mild limb asymmetry, and a grossly retarded bone age. Patients 1, 3, and 4 had isodisomy and patient 2, heterodisomy.
Eggermann et al. (1997) reported 3 patients with SRS and maternal uniparental disomy for chromosome 7. All 3 patients had typical clinical features (IUGR, short stature, typical facial appearance) of SRS, with 2 of them classified as moderately severe.
Dupont et al. (2002) reported a child with SRS who presented with growth retardation with asymmetry and minor facial dysmorphism, including triangular face, without mental retardation. She had an apparently balanced, maternally-inherited reciprocal translocation, and maternal heterodisomy for chromosome 7.
Monk et al. (2002) described 2 SRS patients and 4 probands with pre- and postnatal growth restriction with a range of cytogenetic disruptions of chromosome 7p, including duplications, pericentric inversions, and a translocation. In these 6 novel cases, and 3 previously described probands with duplications, Monk et al. (2002) mapped the breakpoints using FISH probes from a contig of PACs and BACs constructed from the centromere to 7p14. They identified a common breakpoint region within 7p11.2 in all 9 cases, pinpointing this specific interval. They also studied the imprinting status of genes within the 7p14-p11.1 region flanked by the most extreme breakpoints.
By examining 77 families with SRS, Nakabayashi et al. (2002) identified 2 patients with de novo chromosomal rearrangements involving the short arm of chromosome 7. One patient had a partial duplication and was cytogenetically characterized 46,XX,dup(7)(p12p14), and the other patient had a paracentric inversion and was characterized 46,XY,inv(7)(p14p21). The duplication breakpoint interrupted the C7ORF10 gene (609187), and the inversion breakpoint mapped to the 5-prime end of the C7ORF10 gene, possibly just within intron 1. However, Nakabayashi et al. (2002) suggested that the inversion breakpoint may affect both C7ORF10 and C7ORF11, since the 2 genes are separated by less than 100 bp.
Maternal Uniparental Disomy for Chromosome 7
About 10% of SRS cases are due to maternal uniparental disomy of chromosome 7 (summary by Penaherrera et al., 2010).
Eggerding et al. (1994) noted that 3 cases of maternal uniparental disomy for chromosome 7 (mUPD7) had been reported in patients with intrauterine and postnatal growth retardation. Two patients were detected because they were homozygous for a cystic fibrosis mutation for which only the mother was heterozygous (see 219700). One patient was found because he was homozygous for a rare COL1A2 mutation (120160.0030).
Kotzot et al. (1995) investigated 35 patients with either Silver-Russell syndrome or primordial growth retardation and their parents with PCR markers to search for UPD7. Maternal disomy was found in 4 of the 35 patients, including 3 with isodisomy and 1 with heterodisomy. The data confirmed the localization of 1 or more maternally imprinted genes on chromosome 7.
In a prospective study of 33 patients with sporadic Russell-Silver syndrome, Preece et al. (1997) studied the parent of origin of chromosome 7 using variable number tandem repeat (VNTR) or microsatellite repeat markers and identified 2 patients with maternal UPD of chromosome 7. The probands' condition was clinically mild and symmetrical, and showed no gross clinical differences from that of the 30 patients with chromosome 7 derived from both parents.
Eggermann et al. (1997) studied 37 patients with Silver-Russell syndrome using short tandem repeat markers from chromosomes 2, 7, 9, 14, and 16. Uniparental disomy for chromosome 7 was detected in 3 patients. In all 3 cases, it was maternal in origin. In 1 of the 3 families, complete isodisomy was found, and in the other 2 families, the allelic patterns were consistent with partial and complete heterodisomy, respectively. Short tandem repeat typing for uniparental disomy for chromosomes 2, 9, 14, and 16 was unrevealing. All 3 cases with maternal UPD7 had typical clinical features of SRS, with 2 of them classified as moderately severe. One was treated with human growth hormone with good results.
Dupont et al. (2002) reported a case of SRS in a child with an apparently balanced, maternally-inherited reciprocal translocation, t(7;16)(q21;q24), and maternal heterodisomy for chromosome 7. Microsatellite analysis showed a normal biparental inheritance of chromosome 16 but confirmed maternal heterodisomy of chromosome 7. The child presented with growth retardation and minor facial dysmorphism without mental retardation.
Monk et al. (2002) estimated that approximately 10% of SRS cases showed maternal uniparental disomy for chromosome 7. They suggested that the phenotype in these cases may be due to disruption of imprinted gene expression, as opposed to the unmasking of a mutant recessive allele.
Guettard et al. (2008) reported a 35-year-old man with myoclonus-dystonia (159900) and Silver-Russell syndrome. He developed symptoms of myoclonus-dystonia at age 17. Features of SRS included intrauterine growth retardation, short stature, and facial dysmorphism. He did not have mental retardation. Cytogenetic analysis identified mosaicism for a small supernumerary ring chromosome 7, which was considered unlikely to contribute to the phenotype. Microsatellite analysis indicated loss of the paternal allele and maternal UPD7 with maternally imprinted loss of SGCE gene (604149) expression. The findings indicated UPD7 resulted in repression of both alleles of the maternally imprinted SGCE gene, suggesting loss of function of SGCE as the disease mechanism in myoclonus-dystonia. Guettard et al. (2008) suggested that some patients with SRS and similar cytogenetic abnormalities may develop symptoms of myoclonus-dystonia.
Penaherrera et al. (2010) found that 3 of 35 blood samples from patients with SRS had maternal UPD7. All were highly methylated at the SGCE promoter.
Genes on Chromosome 7
In the mouse (and in human as well), the gene encoding growth factor receptor-bound protein-10 (GRB10; 601523) is imprinted. GRB10 protein binds to the insulin receptor (INSR; 147670) and IGF1R via its Src homology 2 domain and inhibits the associated tyrosine kinase activity that is involved in the growth-promoting activities of insulin (INS; 176730) and insulin-like growth factors I (IGF1; 147440) and II (IGF2; 147470). The mouse Grb10 gene is located on proximal chromosome 11. Miyoshi et al. (1998) suggested that, in the mouse, Grb10 is responsible for the imprinted effects of prenatal growth retardation or growth promotion caused by maternal or paternal duplication of proximal chromosome 11 with reciprocal deficiencies, respectively. Based on the location of the human GRB10 gene on 7p12-p11.2 and reports that maternal uniparental disomy 7 may be responsible for Russell-Silver syndrome, Miyoshi et al. (1998) identified GRB10 as a candidate gene for the disorder.
Joyce et al. (1999) estimated that approximately 10% of cases of SRS are associated with maternal uniparental disomy of chromosome 7, suggesting that at least one imprinted gene on chromosome 7 is involved in the pathogenesis of the disease. They reported a proximal 7p interstitial inverted duplication in a mother and daughter, both of whom had features of SRS, including markedly short stature, low birth weight, facial asymmetry, and fifth finger clinodactyly. Fluorescence in situ hybridization with YAC probes enabled delineation of the duplicated region as 7p13-p12.1. This region of proximal 7p is known to be homologous to an imprinted region in mouse chromosome 11 and contains the growth-related genes GRB10, epidermal growth factor receptor (EGFR; 131550), and insulin-like growth factor-binding protein-1 (IGFBP1; 146730), all of which had been suggested as candidate genes for SRS. Molecular analysis in the case of Joyce et al. (1999) showed that the duplication in both mother and daughter spanned a distance of approximately 10 cM and included GRB10 and IGFBP1 but not EGFR. The de novo duplication in the mother was shown to be of paternal origin. To test the hypothesis that submicroscopic duplications of 7p, whether maternal or paternal in origin, are responsible for at least some cases of SRS, they screened a further 8 patients and found duplications of either GRB10 or IGFBP1. The results were thought to suggest that imprinted genes may not underlie the SRS phenotype. Joyce et al. (1999) proposed an alternative hypothesis to explain the occurrence of maternal UPD7 in some cases of SRS. They suggested that SRS may be caused by the inheritance of an additional copy of chromosome 7 material, either as a result of small duplications or undetected trisomy. They pointed out that 6 cases of maternal UPD7 had been shown to have arisen by trisomy rescue. They considered it possible that all cases of maternal UPD7 arise in this way and that an additional copy of the SRS gene(s) in an undetected trisomic cell line is responsible for the phenotype. Somatic mosaicism might help account for the asymmetric growth patterns often seen in SRS, a mechanism implicated in the hemihypertrophy observed in Beckwith-Wiedemann syndrome (130650).
In a study of genetic and phenotypic similarities among patients exhibiting developmental verbal dyspraxia (DVD; 602081), Feuk et al. (2006) studied 7 cases of Russell-Silver syndrome with maternal UPD7. All showed absence of a paternal copy of FOXP2 (605317). All had marked speech delay and difficulties in speech output, particularly articulation. Feuk et al. (2006) considered it noteworthy that while SRS is clinically and genetically heterogeneous, mainly only patients with complete maternal UPD7 (approximately 10%) exhibit DVD. These and other observations suggested that absence of paternal FOXP2 is the cause of DVD in SRS.
Wakeling et al. (2000) studied the imprinting status of IGFBP1 and IGFBP3 (146732) in normal fetuses and in patients with SRS. Biallelic expression of both genes was found in normal fetal tissue and in 2 SRS patients with UPD7 and 4 SRS patients without UPD7. Wakeling et al. (2000) concluded that IGFBP1 and IGFBP3 were unlikely to be involved in SRS.
Monk et al. (2000) identified a de novo duplication of 7p13-p11.2 in a 5-year-old girl with features characteristic of SRS. FISH confirmed the presence of a tandem duplication encompassing the GRB10, IGFBP1, and IGFBP3 genes, but not the EGFR gene. Microsatellite markers showed that the duplication was of maternal origin. These findings provided the first evidence that SRS may result from overexpression of a maternally expressed imprinted gene, rather than from absent expression of a paternally expressed gene. The GRB10 gene lies within the duplicated region and was considered to be a strong candidate, since it is a known growth repressor. Monk et al. (2000) demonstrated that the GRB10 genomic interval replicates asynchronously in human lymphocytes, suggestive of imprinting. An additional 36 SRS probands were investigated for duplication of GRB10, but none was found. However, it remained possible that GRB10 and/or other genes within 7p13-p11.2 are responsible for some cases of SRS.
Yoshihashi et al. (2000) performed mutation analysis of the GRB10 gene in 58 unrelated patients with SRS and identified a pro95-to-ser substitution within the N-terminal domain in 2 of the patients. However, Hannula et al. (2001), Hitchins et al. (2001), and McCann et al. (2001) presented evidence creating uncertainty about the role of the GRB10 gene in Russell-Silver syndrome.
Among 11 patients with RSS, Martinez et al. (2001) found no molecular evidence for duplication of chromosomal segment 7p11.2-p13.
Hannula et al. (2001) studied 4 patients with maternal UPD7 and argued that they might compose a distinct phenotypic entity among Silver-Russell syndrome patients with a mild phenotype. In a systematic screening with microsatellite markers for maternal UPD of chromosome 7 in patients with SRS, Hannula et al. (2001) identified a patient with a small segment of matUPD7 (7q31-qter) and biparental inheritance of the remainder of the chromosome. The pattern was thought to be explained by somatic recombination in the zygote. The matUPD7 segment extended for 35 Mb and included the imprinted gene cluster of PEG1/MEST (601029) and COPG2 (604355) at 7q32. GRB10 at 7p12-p11.2 was located within the region of biparental inheritance in this case.
Hitchins et al. (2001) used expressed polymorphisms to determine the imprinting status of the GRB10 gene in multiple human fetal tissues. Expression from the paternal allele was exclusive in the spinal cord and predominant in fetal brain, whereas expression from both parental alleles was detected in a wide range of other organs and peripheral tissues. The role GRB10 might play in the etiology of RSS involving chromosome 7 was difficult to predict in view of the imprinting profile of the gene. Further doubt about the role of GRB10 in RSS was cast by the absence of mutations detected by sequencing in 18 classic RSS patients, where major structural chromosomal abnormalities and matUPD7 had previously been excluded. McCann et al. (2001) likewise cast doubt on the role of GRB10 in Silver-Russell syndrome. Using RT-PCR, they confirmed that GRB10 imprinting in brain and muscle is isoform specific, and they demonstrated absence of imprinting in growth plate cartilage, the tissue most directly involved in linear growth. Thus, they considered it unlikely that GRB10 is the gene responsible for SRS.
Abu-Amero et al. (2008) provided a review of the complex genetic etiology of Silver-Russell syndrome, which primarily involves chromosomes 7 and 11.
Abu-Amero, S., Monk, D., Frost, J., Preece, M., Stanier, P., Moore, G. E. The genetic aetiology of Silver-Russell syndrome. J. Med. Genet. 45: 193-199, 2008. [PubMed: 18156438] [Full Text: https://doi.org/10.1136/jmg.2007.053017]
Dupont, J.-M., Cuisset, L., Cartigny, M., Le Tessier, D., Vasseur, C., Rabineau, D., Jeanpierre, M. Familial reciprocal translocation t(7;16) associated with maternal uniparental disomy 7 in a Silver-Russell patient. Am. J. Med. Genet. 111: 405-408, 2002. [PubMed: 12210300] [Full Text: https://doi.org/10.1002/ajmg.10570]
Eggerding, F. A., Schonberg, S. A., Chehab, F. F., Norton, M. E., Cox, V. A., Epstein, C. J. Uniparental isodisomy for paternal 7p and maternal 7q in a child with growth retardation. Am. J. Hum. Genet. 55: 253-265, 1994. [PubMed: 7913578]
Eggermann, T., Wollmann, H. A., Kuner, R., Eggermann, K., Enders, H., Kaiser, P., Ranke, M. B. Molecular studies in 37 Silver-Russell syndrome patients: frequency and etiology of uniparental disomy. Hum. Genet. 100: 415-419, 1997. [PubMed: 9272165] [Full Text: https://doi.org/10.1007/s004390050526]
Feuk, L., Kalervo, A., Lipsanen-Nyman, M., Skaug, J., Nakabayashi, K., Finucane, B., Hartung, D., Innes, M., Kerem, B., Nowaczyk, M. J., Rivlin, J., Roberts, W., and 11 others. Absence of a paternally inherited FOXP2 gene in developmental verbal dyspraxia. Am. J. Hum. Genet. 79: 965-972, 2006. [PubMed: 17033973] [Full Text: https://doi.org/10.1086/508902]
Guettard, E., Portnoi, M.-F., Lohmann-Hedrich, K., Keren, B., Rossignol, S., Winkler, S., El Kamel, I., Leu, S., Apartis, E., Vidailhet, M., Klein, C., Roze, E. Myoclonus-dystonia due to maternal uniparental disomy. Arch. Neurol. 65: 1380-1385, 2008. [PubMed: 18852357] [Full Text: https://doi.org/10.1001/archneur.65.10.1380]
Hannula, K., Kere, J., Pirinen, S., Holmberg, C., Lipsanen-Nyman, M. Do patients with maternal uniparental disomy for chromosome 7 have a distinct mild Silver-Russell phenotype? (Letter) J. Med. Genet. 38: 273-278, 2001. [PubMed: 11370636] [Full Text: https://doi.org/10.1136/jmg.38.4.273]
Hannula, K., Lipsanen-Nyman, M., Kontiokari, T., Kere, J. A narrow segment of maternal uniparental disomy of chromosome 7q31-qter in Silver-Russell syndrome delimits a candidate gene region. Am. J. Hum. Genet. 68: 247-253, 2001. [PubMed: 11112662] [Full Text: https://doi.org/10.1086/316937]
Hitchins, M. P., Monk, D., Bell, G. M., Ali, Z., Preece, M. A., Stanier, P., Moore, G. E. Maternal repression of the human GRB10 gene in the developing central nervous system; evaluation of the role for GRB10 in Silver-Russell syndrome. Europ. J. Hum. Genet. 9: 82-90, 2001. [PubMed: 11313740] [Full Text: https://doi.org/10.1038/sj.ejhg.5200583]
Joyce, C. A., Sharp, A., Walker, J. M., Bullman, H., Temple, I. K. Duplication of 7p12.1-p13, including GRB10 and IGFBP1, in a mother and daughter with features of Silver-Russell syndrome. Hum. Genet. 105: 273-280, 1999. [PubMed: 10987657] [Full Text: https://doi.org/10.1007/s004390051101]
Kotzot, D., Schmitt, S., Bernasconi, F., Robinson, W. P., Lurie, I. W., Ilyina, H., Mehes, K., Hamel, B. C. J., Otten, B. J., Hergersberg, M., Werder, E., Schoenle, E., Schinzel, A. Uniparental disomy 7 in Silver-Russell syndrome and primordial growth retardation. Hum. Molec. Genet. 4: 583-587, 1995. [PubMed: 7633407] [Full Text: https://doi.org/10.1093/hmg/4.4.583]
Martinez, M.-J., Binkert, F., Schinzel, A., Kotzot, D. No evidence of dup(7)(p11.2p13) in Silver-Russell syndrome. (Letter) Am. J. Med. Genet. 99: 335-337, 2001. [PubMed: 11252004] [Full Text: https://doi.org/10.1002/1096-8628(2001)9999:9999<::aid-ajmg1177>3.0.co;2-q]
McCann, J. A., Zheng, H., Islam, A., Goodyer, C. G., Polychronakos, C. Evidence against GRB10 as the gene responsible for Silver-Russell syndrome. Biochem. Biophys. Res. Commun. 286: 943-948, 2001. [PubMed: 11527390] [Full Text: https://doi.org/10.1006/bbrc.2001.5500]
Miyoshi, N., Kuroiwa, Y., Kohda, T., Shitara, H., Yonekawa, H., Kawabe, T., Hasegawa, H., Barton, S. C., Surani, M. A., Kaneko-Ishino, T., Ishino, F. Identification of the Meg1/Grb10 imprinted gene on mouse proximal chromosome 11, a candidate for the Silver-Russell syndrome gene. Proc. Nat. Acad. Sci. 95: 1102-1107, 1998. [PubMed: 9448292] [Full Text: https://doi.org/10.1073/pnas.95.3.1102]
Monk, D., Bentley, L., Hitchins, M., Myler, R. A., Clayton-Smith, J., Ismail, S., Price, S. M., Preece, M. A., Stanier, P., Moore, G. E. Chromosome 7p disruptions in Silver Russell syndrome: delineating an imprinted candidate gene region. Hum. Genet. 111: 376-387, 2002. [PubMed: 12384779] [Full Text: https://doi.org/10.1007/s00439-002-0777-4]
Monk, D., Wakeling, E. L., Proud, V., Hitchins, M., Abu-Amero, S. N., Stanier, P., Preece, M. A., Moore, G. E. Duplication of 7p11.2-p13, including GRB10, in Silver-Russell syndrome. Am. J. Hum. Genet. 66: 36-46, 2000. [PubMed: 10631135] [Full Text: https://doi.org/10.1086/302717]
Nakabayashi, K., Fernandez, B. A., Teshima, I., Shuman, C., Proud, V. K., Curry, C. J., Chitayat, D., Grebe, T., Ming, J., Oshimura, M., Meguro, M., Mitsuya, K., Deb-Rinker, P., Herbrick, J., Weksberg, R., Scherer, S. W. Molecular genetics studies of human chromosome 7 in Russell-Silver syndrome. Genomics 79: 186-196, 2002. [PubMed: 11829489] [Full Text: https://doi.org/10.1006/geno.2002.6695]
Penaherrera, M. S., Weindler, S., Van Allen, M. I., Yong, S.-L., Metzger, D. L., McGillivray, B., Boerkoel, C., Langlois, S., Robinson, W. P. Methylation profiling in individuals with Russell-Silver syndrome. Am. J. Med. Genet. 152A: 347-355, 2010. [PubMed: 20082469] [Full Text: https://doi.org/10.1002/ajmg.a.33204]
Preece, M. A., Price, S. M., Davies, V., Clough, L., Stanier, P., Trembath, R. C., Moore, G. E. Maternal uniparental disomy 7 in Silver-Russell syndrome. J. Med. Genet. 34: 6-9, 1997. [PubMed: 9032641] [Full Text: https://doi.org/10.1136/jmg.34.1.6]
Wakeling, E. L., Hitchins, M. P., Abu-Amero, S. N., Stanier, P., Moore, G. E., Preece, M. A. Biallelic expression of IGFBP1 and IGFBP3, two candidate genes for the Silver-Russell syndrome. J. Med. Genet. 37: 65-67, 2000. [PubMed: 10691413] [Full Text: https://doi.org/10.1136/jmg.37.1.65]
Yoshihashi, H., Maeyama, K., Kosaki, R., Ogata, T., Tsukahara, M., Goto, Y., Hata, J., Matsuo, N., Smith, R. J., Kosaki, K. Imprinting of human GRB10 and its mutations in two patients with Russell-Silver syndrome. Am. J. Hum. Genet. 67: 476-482, 2000. [PubMed: 10856193] [Full Text: https://doi.org/10.1086/302997]