Fragile X Syndrome in Mentally Retarded Patients from Latvia

Daneberga, Zanda; Krūmiņa, Zita; Lāce, Baiba; Bauze, Daiga; Proņina, Natālija; Lugovska, Rita

doi:10.2478/v10046-009-0021-x

Abstract

The aim of this study was to estimate the prevalence of FXS in Latvia and characterise the FMR1 CGG-repeat structure in Latvian patients exhibiting mental retardation. A group of 352 unrelated patients with mental retardation (MR) referred from clinical geneticists was screened by PCR for the normal allele. In a sample of 245 chromosomes the CGG repeat number was determined by Applied Biosystems protocol on ABI Prism 310. Prevalence of 29, 30, and 31 CGG repeats was found for the normal allele. Five affected patients were detected (detection rate 2.56%). AGG interspersion pattern analysis showed stability of transmission to the next generation for 12 intermediate alleles. The found detection rate of FXS in our survey among MR patients was similar to the detection rate reported in literature. Taking into account the number of confirmed FXS cases we suggest that FXS is still clinically unrecognized in paediatrician practice.

References

Chong, S.S., Eichler, E. E., Nelson, D.L., Hughes, M. R. (1994). Robust amplification and ethidium --- visible detection of the fragile X syndrome CGG repeat using Pfu polymerase. Amer. J. Med. Genet., 51, 522--526.
Search in Google Scholar
Crawford, D.C., Acun, J.M., Sherman, S.L. (2001). FMR1 and the fragile X syndrome: Human genome epidemiology review. Genet. Med., 3, 359--371.10.1097/00125817-200109000-00006
Search in Google Scholar
Eichler, E.E., Holden, J.J.A., Popovich, B.W., Reiss, A.L., Snow, K., Thi-bodeau, S.N., Richards, C.S., Word, P.A., Nelson, D.L. (1994). Length of uninterrupted CGG repeats determines instability in the FMR1 gene. Nat. Genet. 8, 88--94.10.1038/ng0994-88
Search in Google Scholar
Fu, J.H., Kuhl, D.P., Pizzuti, A., Pieretti, M., Sutcliffe, J.S., Richards Verkerk, A.J., Holden, J.J., Fenwick, R.G., Jr., Warren, S.T. (1991). Variation of the CGG repeat at the fragile X site results in genetic instability: Resolution of the Sherman paradox. Cell 67, 1047--1058.10.1016/0092-8674(91)90283-5
Search in Google Scholar
Ropers, H.H., Hamel, B.C. (2005) X-linked mental retardation. Nat. Rev. Genet. 6, 46--57.10.1038/nrg1501
Search in Google Scholar
Turner, G., Webb, T., Wake, S., Robinson, H. (1996) Prevalence of fragile X syndrome. Amer. J. Med. Genet., 64, 196--197.10.1002/(SICI)1096-8628(19960712)64:1<;196::AID-AJMG35>3.0.CO;2-G
Search in Google Scholar
Verkerk, A.J.M.H., Pieretti, M., Suteliffe, J.S., et al. (1991) Identification of a gene (FMR-1) containing a CGG repeat coincident with a breakpoint cluster region exibiting length variation in fragile X syndrome. Cell, 65, 905--914.
Search in Google Scholar
Yim, S.Y., Jeon, B.H., Yang, J.A., Kim, H.J. (2008). Fragile X syndrome in Korea: A case series and a review of the literature. J. Korean Med. Sci., 23, 470--476.10.3346/jkms.2008.23.3.470
Search in Google Scholar

Fragile X Syndrome in Mentally Retarded Patients from Latvia

Abstract

Paradigm

My account