Clinical-neurologic, cytogenetic and molecular aspects of the Prader-Willi and Angelman Syndromes

Pina-Neto, João M. de; Ferraz, Victor Evangelista F.; Molfetta, Greice Andreotti de; Buxton, Jess; Richards, Sarah; Malcolm, Sue

doi:10.1590/S0004-282X1997000200006

Abstracts

The Prader-Willi syndrome (PWS) and the Angelman syndrome (AS) are human neurogenetic disorders involving the imprinting mechanism, at the 15q11-13 chromosome region. The predominant genetic defects in PW are 15q 11-13 deletions of paternal origin and maternal chromosome 15 uniparental disomy. In contrast, maternal deletions and paternal chromosome 15 uniparental disomy are associated with a different neurogenetic disorder, the AS. In both disorders, these mutations are associated with parent-of-origin specific methylation at several 15q 11-13 loci. We studied 5 patients suspect of PWS and 4 patients suspect of AS who were referred to the Medical Genetics Unit at the University Hospital of Medical School from Ribeirão Preto. Our objective was to establish the correct clinical and etiological diagnosis in these cases. We used conventional cytogenetics, methylation analysis with the probe KB 17 (CpG island of the SNRPN gene) by Southern blotting after digestion with the Xba I and Not I restriction enzymes. We studied in patients and their parents the segregation of the (CA)n repeats polymorphisms by PCR, using the primers 196 and IR4-3R. All the patients had normal conventional cytogenetical analysis. We confirmed 3 cases of PWS: one by de novo deletion, one by maternal chromosome 15 uniparental disomy and one case with no defined cause determined by the used primers. We confirmed 2 cases of AS, caused by de novo deletion at the 15q 11-13 region, and one case with normal molecular analysis but with strong clinical characteristics.

medical genetics; mental retardation; Prader-Willi syndrome; Angelman syndrome; molecular genetics; PCR (polymerase chan reaction); Southern blot

A síndrome de Prader-Willi (SPW) e a síndrome de Angelman (SA) são doenças neurogenéticas consideradas como exemplos do fenômeno de imprinting em seres humanos, estando relacionadas com alterações envolvendo a região cromossômica 15q11-13. As alterações genéticas predominantes na SPW são deleções na região 15q 11-13 de origem paterna e dissomia uniparental materna. Na SA encontra-se deleções na região 15q 11-13 materna e dissomia uniparental paterna. Estudamos 5 pacientes com suspeita clínica de SPW e 4 pacientes com suspeita clínica de SA atendidos no Setor de Genética Médica do Hospital Universitário da FMRP-USP, com o objetivo de estabelecer o diagnóstico clínico e etiológico de certeza nessa amostra. Para isso utilizamos citogenética convencional, estudo de metilação por Southern blotting utilizando a sonda KB 17 (ilha CpG do gene SNRPN) após digestão com as enzimas de restrição Xba I e Not I e análise de polimorfismos de repetição de CA por PCR, usando os primers 196 e IR4-3R. Dos 9 pacientes avaliados, todos tiveram avaliação citogenética convencional normal. Foram confirmados a nível molecular, 1 caso de SPW por deleção nova, 1 caso de SPW por dissomia uniparental materna e 1 caso de SPW em que a causa genética não pode ser esclarecida pela análise de polimorfismo com os primers usados. Foram confirmados a nível molecular 2 casos de SA, ambos por deleção nova na região 15q 11-13, e 1 caso de SA cuja clínica é extremamente sugestiva mas no qual não foi evidenciada alteração em qualquer dos exames moleculares utilizados.

genética médica; deficiência mental; síndrome de Prader-Willi; síndrome de Angelman; genética molecular; PCR (polymerase chain reaction); Southern blot

Clinical-neurologic, cytogenetic and molecular aspects of the Prader-Willi and Angelman Syndromes

Aspectos clínico-neurológicos, citogenéticos e moleculares das síndromes de Prader-Willi e Angelman

João M. de Pina-Neto^I; Victor Evangelista F. Ferraz^I; Greice Andreotti de Molfetta^I; Jess Buxton^II; Sarah Richards^II; Sue Malcolm^II

^IDepartment of Genetics, Medical School of Riberião Preto - University of São Paulo (FMRP-USP)

^IIMolecuIar Genetics Unit, Institute of Child Health, University of London

ABSTRACT

The Prader-Willi syndrome (PWS) and the Angelman syndrome (AS) are human neurogenetic disorders involving the imprinting mechanism, at the 15q11-13 chromosome region. The predominant genetic defects in PW are 15q 11-13 deletions of paternal origin and maternal chromosome 15 uniparental disomy. In contrast, maternal deletions and paternal chromosome 15 uniparental disomy are associated with a different neurogenetic disorder, the AS. In both disorders, these mutations are associated with parent-of-origin specific methylation at several 15q 11-13 loci. We studied 5 patients suspect of PWS and 4 patients suspect of AS who were referred to the Medical Genetics Unit at the University Hospital of Medical School from Ribeirão Preto. Our objective was to establish the correct clinical and etiological diagnosis in these cases. We used conventional cytogenetics, methylation analysis with the probe KB 17 (CpG island of the SNRPN gene) by Southern blotting after digestion with the Xba I and Not I restriction enzymes. We studied in patients and their parents the segregation of the (CA)_n repeats polymorphisms by PCR, using the primers 196 and IR4-3R. All the patients had normal conventional cytogenetical analysis. We confirmed 3 cases of PWS: one by de novo deletion, one by maternal chromosome 15 uniparental disomy and one case with no defined cause determined by the used primers. We confirmed 2 cases of AS, caused by de novo deletion at the 15q 11-13 region, and one case with normal molecular analysis but with strong clinical characteristics.

Key words: medical genetics, mental retardation, Prader-Willi syndrome, Angelman syndrome, molecular genetics, PCR (polymerase chan reaction), Southern blot.

RESUMO

A síndrome de Prader-Willi (SPW) e a síndrome de Angelman (SA) são doenças neurogenéticas consideradas como exemplos do fenômeno de imprinting em seres humanos, estando relacionadas com alterações envolvendo a região cromossômica 15q11-13. As alterações genéticas predominantes na SPW são deleções na região 15q 11-13 de origem paterna e dissomia uniparental materna. Na SA encontra-se deleções na região 15q 11-13 materna e dissomia uniparental paterna. Estudamos 5 pacientes com suspeita clínica de SPW e 4 pacientes com suspeita clínica de SA atendidos no Setor de Genética Médica do Hospital Universitário da FMRP-USP, com o objetivo de estabelecer o diagnóstico clínico e etiológico de certeza nessa amostra. Para isso utilizamos citogenética convencional, estudo de metilação por Southern blotting utilizando a sonda KB 17 (ilha CpG do gene SNRPN) após digestão com as enzimas de restrição Xba I e Not I e análise de polimorfismos de repetição de CA por PCR, usando os primers 196 e IR4-3R. Dos 9 pacientes avaliados, todos tiveram avaliação citogenética convencional normal. Foram confirmados a nível molecular, 1 caso de SPW por deleção nova, 1 caso de SPW por dissomia uniparental materna e 1 caso de SPW em que a causa genética não pode ser esclarecida pela análise de polimorfismo com os primers usados. Foram confirmados a nível molecular 2 casos de SA, ambos por deleção nova na região 15q 11-13, e 1 caso de SA cuja clínica é extremamente sugestiva mas no qual não foi evidenciada alteração em qualquer dos exames moleculares utilizados.

Palavras-chave: genética médica; deficiência mental; síndrome de Prader-Willi; síndrome de Angelman; genética molecular; PCR (polymerase chain reaction); Southern blot.

Texto completo disponível apenas em PDF.

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Aceite: 17-fevereiro-1997.

Dr. João Monteiro de Pina Neto - Departamento de Genética, Faculdade de Medicina de Ribeirão Preto USP - Av. Bandeirantes 3900 - 14049-900 Ribeirão Preto SP - Brasil. Email:imdpneto@fmrp.usp.br

1. Angelman H. Puppet children. Dev Med Child Neurol 1965;7:681-688.
2. Boyd SG, Harden A. Pattern, MA. The EEG in early diagnosis of the Angelman (happy puppet) syndrome. Eur J Pedialr 1988;147:508-513.
3. Buxton JL, Chan CT. Gilbert H, Clayton-Smith J, Burne J, Pembrey M, Malcolm S. Angelman syndrome associated with the maternal 15q 11 -13 deletion of less than 200Kb. Hum Mol Genet 1994;3:1409-1413.
4. Cassidy SB, Lai LW, Erickson RP, Magnuson L, Thomas E, Gendron R, Herrmann J. Trisomy 15 with loss of the paternal 15 as a cause of Prader-Willi syndrome dueto maternal disomy. Am J Hum Genet 1992;51:701-708.
5. Chan C-TJ, Clayton-Smith J, Cheng X-J, Buxton J, Webb T, Pembrey ME, Malcolm S. Molecular mechanisms in Angelman syndrome: a survey of 93 patients. J Med Genet 1993;30:895-902.
6. Clayton-Smith J, Pembrey ME. Angelman Syndrome. J Med Genet 1992;29:412-415.
7. Dittrich B, Buiting K. Gross S, Horsthemke B. Characterization of a methylation imprint in the Prader-Willi syndrome chromosome region. Hum Mol Genet 1993;2:1995-1999.
8. Donaldson MDC. Chu CE, Cooke A, Wilson A, Greene SA, Stephenson JHP. The Prader-Willi syndrome. Arch Dis Child 1993;70:58-63.
9. Erdel M, Schuffcnhauer S, Buchhotz B, Barth-Witte U, Köchl S, Utermann B, Duba H, Utermann G. Routine screening for microdeletions by FISH in 77 patients suspected of having Prader-Willi or Angelman syndromes using YAC clone 273A2 (DI5S10). Hum Genet 1996;97:784-793.
¹⁰
GDB(TM) Genome Database [database online]. Baltimore (Maryland, USA): Johns Hopkins University, 1990-. Updated daily, [cited 22 Nov 1995 ]. GDB Data Type: Polymorphism. Accession ID: GDB: 698720. Available from Internet: <URL:http:// gdbwww.gdb.org/>
» link
11. Glenn CC, Nicholls RD, Robinson WP, Saitoh S, Niikawa N, Schinzel A, Horsthemke B, Driscoll DJ. Modification of 15q 11 -13 DNA methylation imprints in unique Angelman and Prader-Willi patients. Hum Mol Genet 1993;2:1377-1382.
12. Glenn CC. Saitoh S. Jong MTC, Filbrandt MM, Surti U, Driscoll DJ, Nicholls RD. Gene structure, DNA methylations. and imprinted expression of the Human SNRPN Gene. Am J Hum Genet 1996;58:335-346.
13. Holm VA, Cassidy SB, Butler MG. Hanchett JM, Greenswag LR, Whitman BY, Greenberg F. Prader-Willi syndrome: consensus diagnostic criteria. Pediatrics 1993;91:398-402.
14. Mascari MJ, Gottlieb W. Rogan PK, Butler MG, Waller DA, Armour JAL, Jeffreys AJ, Ladda RL. Nicholls RD. The frequency of uniparental disomy in Prader-Willi syndrome - implications for molecular diagnosis. New Engl J Med 1992,326:1599-1607.
15. Moorhead PS, Nowell PG, Mellman WJ, Batipps OM, Hungerford DA. Chromosome preparation of leukocyte cultures from peripheral hood. ExperCell Res 1960;20:613-616.
16. Mutirangura A. Greenberg F. Butler MG, Malcolm S, Nicholls RD, Chakravarti A, Ledbetter DH. Multiplex PCR of three dinucleotide repeats in the Prader-Willi/Angelman critical region (15q 11-13): molecular diagnosis of uniparental disomy. Hum Mol Genet 1993;2:143-151.
17. Mutirangura A. Kuwano A, Ledbetter AS, Chinault AC, Ledbetter DH. Dinucleotide repeat polymorphism at the D15S11 locus in the Angel man/Prader- Willi region (AS/PWS) of chromosome 15. Hum Mol Genet 1992;1:139.
18. Prader A. Labhart A, Willi H. Ein Syndrom von Adipositas, Kleinwuchs, Kryptorchismus und Oligophrenie nach myatomcartigem Zustund im neugeborenenalter. Schweiz Med Wochenschr 1956,86:1260-1261.
19. Robinson WP, Bottani A, Xie YG, Balakrishman J, Binkert F, Machler M, Prader A, Schinzel A. Molecular, cytogenetic, and clinical investigations of Prader-Willi syndrome patients. Am J Hum Genet 1991 ;49:1219-1234.
20. Scheres JM. Human Chromosome banding. Lancet 1972;I:849.
21. Smeets DFCM, Hamel BCJ, Nelen MR, Smeets HJM, Bollen JHM, Smits APT, Ropers HH, Oost BA. Prader-Willi syndrome and Angelman syndrome in cousins from a family with a translocation between chromosome 6 and 15. N Engl J Med 1992:326:807-811.
22. van den Ouweland AM, van der Est MN, Wesby-van Swaay E, Tijmensen TS, Los FJ, van Hemel JO, Hennekam RC, Meijers-Heijboer HJ, Niermeijer MF, Halley DJ. DNA diagnosis of Prader-Willi and Angelman syndromes with the probe PW71 (Dl5S63). Hum Genet 1995;95:562-567.
23. Willems PJ, Kijkstra I, Brouwer OF, Smit GPA. Recurrence risk in the Angelman ("Happy-Puppet") syndrome. Am J Med Genet 1987;27:773-780.
24. Williams CA, Angelman H, Clayton-Smith J, Driscoll DJ, Hendrickson JE, Knoll JHM, Magenis RE, Schinzel A, Wagstaff J.Whidden EM, Zori RT. Angelman syndrome: consensus for diagnostic criteria. Am J Med Genet 1995;56:237-238.

Publication Dates

Publication in this collection
10 Nov 2010
Date of issue
June 1997

History

Received
17 Feb 1997

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

[1] 1. Angelman H. Puppet children. Dev Med Child Neurol 1965;7:681-688.

[2] 2. Boyd SG, Harden A. Pattern, MA. The EEG in early diagnosis of the Angelman (happy puppet) syndrome. Eur J Pedialr 1988;147:508-513.

[3] 3. Buxton JL, Chan CT. Gilbert H, Clayton-Smith J, Burne J, Pembrey M, Malcolm S. Angelman syndrome associated with the maternal 15q 11 -13 deletion of less than 200Kb. Hum Mol Genet 1994;3:1409-1413.

[4] 4. Cassidy SB, Lai LW, Erickson RP, Magnuson L, Thomas E, Gendron R, Herrmann J. Trisomy 15 with loss of the paternal 15 as a cause of Prader-Willi syndrome dueto maternal disomy. Am J Hum Genet 1992;51:701-708.

[5] 5. Chan C-TJ, Clayton-Smith J, Cheng X-J, Buxton J, Webb T, Pembrey ME, Malcolm S. Molecular mechanisms in Angelman syndrome: a survey of 93 patients. J Med Genet 1993;30:895-902.

[6] 6. Clayton-Smith J, Pembrey ME. Angelman Syndrome. J Med Genet 1992;29:412-415.

[7] 7. Dittrich B, Buiting K. Gross S, Horsthemke B. Characterization of a methylation imprint in the Prader-Willi syndrome chromosome region. Hum Mol Genet 1993;2:1995-1999.

[8] 8. Donaldson MDC. Chu CE, Cooke A, Wilson A, Greene SA, Stephenson JHP. The Prader-Willi syndrome. Arch Dis Child 1993;70:58-63.

[9] 9. Erdel M, Schuffcnhauer S, Buchhotz B, Barth-Witte U, Köchl S, Utermann B, Duba H, Utermann G. Routine screening for microdeletions by FISH in 77 patients suspected of having Prader-Willi or Angelman syndromes using YAC clone 273A2 (DI5S10). Hum Genet 1996;97:784-793.

[10] ¹⁰
GDB(TM) Genome Database [database online]. Baltimore (Maryland, USA): Johns Hopkins University, 1990-. Updated daily, [cited 22 Nov 1995 ]. GDB Data Type: Polymorphism. Accession ID: GDB: 698720. Available from Internet: <URL:http:// gdbwww.gdb.org/>
» link

[11] 11. Glenn CC, Nicholls RD, Robinson WP, Saitoh S, Niikawa N, Schinzel A, Horsthemke B, Driscoll DJ. Modification of 15q 11 -13 DNA methylation imprints in unique Angelman and Prader-Willi patients. Hum Mol Genet 1993;2:1377-1382.

[12] 12. Glenn CC. Saitoh S. Jong MTC, Filbrandt MM, Surti U, Driscoll DJ, Nicholls RD. Gene structure, DNA methylations. and imprinted expression of the Human SNRPN Gene. Am J Hum Genet 1996;58:335-346.

[13] 13. Holm VA, Cassidy SB, Butler MG. Hanchett JM, Greenswag LR, Whitman BY, Greenberg F. Prader-Willi syndrome: consensus diagnostic criteria. Pediatrics 1993;91:398-402.

[14] 14. Mascari MJ, Gottlieb W. Rogan PK, Butler MG, Waller DA, Armour JAL, Jeffreys AJ, Ladda RL. Nicholls RD. The frequency of uniparental disomy in Prader-Willi syndrome - implications for molecular diagnosis. New Engl J Med 1992,326:1599-1607.

[15] 15. Moorhead PS, Nowell PG, Mellman WJ, Batipps OM, Hungerford DA. Chromosome preparation of leukocyte cultures from peripheral hood. ExperCell Res 1960;20:613-616.

[16] 16. Mutirangura A. Greenberg F. Butler MG, Malcolm S, Nicholls RD, Chakravarti A, Ledbetter DH. Multiplex PCR of three dinucleotide repeats in the Prader-Willi/Angelman critical region (15q 11-13): molecular diagnosis of uniparental disomy. Hum Mol Genet 1993;2:143-151.

[17] 17. Mutirangura A. Kuwano A, Ledbetter AS, Chinault AC, Ledbetter DH. Dinucleotide repeat polymorphism at the D15S11 locus in the Angel man/Prader- Willi region (AS/PWS) of chromosome 15. Hum Mol Genet 1992;1:139.

[18] 18. Prader A. Labhart A, Willi H. Ein Syndrom von Adipositas, Kleinwuchs, Kryptorchismus und Oligophrenie nach myatomcartigem Zustund im neugeborenenalter. Schweiz Med Wochenschr 1956,86:1260-1261.

[19] 19. Robinson WP, Bottani A, Xie YG, Balakrishman J, Binkert F, Machler M, Prader A, Schinzel A. Molecular, cytogenetic, and clinical investigations of Prader-Willi syndrome patients. Am J Hum Genet 1991 ;49:1219-1234.

[20] 20. Scheres JM. Human Chromosome banding. Lancet 1972;I:849.

[21] 21. Smeets DFCM, Hamel BCJ, Nelen MR, Smeets HJM, Bollen JHM, Smits APT, Ropers HH, Oost BA. Prader-Willi syndrome and Angelman syndrome in cousins from a family with a translocation between chromosome 6 and 15. N Engl J Med 1992:326:807-811.

[22] 22. van den Ouweland AM, van der Est MN, Wesby-van Swaay E, Tijmensen TS, Los FJ, van Hemel JO, Hennekam RC, Meijers-Heijboer HJ, Niermeijer MF, Halley DJ. DNA diagnosis of Prader-Willi and Angelman syndromes with the probe PW71 (Dl5S63). Hum Genet 1995;95:562-567.

[23] 23. Willems PJ, Kijkstra I, Brouwer OF, Smit GPA. Recurrence risk in the Angelman ("Happy-Puppet") syndrome. Am J Med Genet 1987;27:773-780.

[24] 24. Williams CA, Angelman H, Clayton-Smith J, Driscoll DJ, Hendrickson JE, Knoll JHM, Magenis RE, Schinzel A, Wagstaff J.Whidden EM, Zori RT. Angelman syndrome: consensus for diagnostic criteria. Am J Med Genet 1995;56:237-238.