© 7992 Oxford University Press
Human Molecular Genetics, Vol. 1, No. 6 443—444
Deletion in the prion protein gene in a demented patient J.F.Diedrich, D.S.Knopman1, J.F.List, K.Olson, W.H.Frey II 3 , C.R.Emory3, J.H.Sung12 and A.T.Haase* Department of Microbiology, department of Neurology and laboratory of Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, and 3Neurdogy Research Laboratories, St Paul-Ramsey Medical Center, St Paul, MN 55101, USA Received April 13, 1992; Revised and Accepted July 20, 1992
* To whom correspondence should be addressed
suggest that the prevalence of these deletions may be as high as 2.5% in the general population (8). Although the deletion in this patient's PrP gene may be coincidental, the dementia, central nervous system vacuolation, and the exclusion of other diagnoses in combination with the PrP gene mutation are certainly compatible with prion disease. While the relationship between the deletion of a single octapeptide repeat in the PrP gene and dementia is unclear, this study calls for further analysis to determine if deletions predispose to neurologic disease. REFERENCES 1. 2. 3. 4.
Owen.F., Lofthouse,R., Crow,T.J. et al. (1989) Lancet I, 51-52. Hsiao.K., Baker.H.R, Crow,T.J. et al. (1989) Nature 338, 342-344. Hsiao,K.K., Scott,M., Foster.D. et al. (1990) Science 250, 1587-1590. Knopman.D.S., Mastri.A.R., Frey.W.H., SungJ.H. and Rustan.T. (1990) Neurology 40, 251-256.
bp
371 -
327-298
Figure 1. PrP coding sequences amplified by PCR and digested with Pstl Tissues were collected by the St Paul Ramsey-University of Minnesota Brain Bank between 1980 and 1986. A group of demented patients were identified that did not have histopathological changes diagnostic for Alzheimer's disease or other categories of dementia that are pathologically well established (4). At autopsy, the brains were bisected in the midsagittal plane. One half of the brain was frozen as 10 coronal sections. Genomic DNA was extracted from frozen prefrontal cortex using standard techniques. In the case of the nondemented control, genomic DNA was extracted from peripheral blood. The PrP coding sequences were amplified using the PCR primers ATGCTGGTTCTCTTTGTGCXrCACATGGAGTGACCT and ACAGGTGGAGAGGAGAAGAGGACCATGCTCGATCC. The 698 bp PCR product was gel-purified, digested with Pstl, electrophoresed in an 8% polyacrylamide gel, and stained with ethidium bromide. The lengths of the DNA markers (M) in base pairs (bp) are shown in the right margin, and the lengths of the two expected DNA bands are shown in the left margin. The arrow indicates the additional band at approximately 300 bp in one individual. Lanes 1 through 5, demented patients; lane 6, nondemented control.
Downloaded from http://hmg.oxfordjournals.org/ at University of Glasgow on June 28, 2015
It is important to characterize mutations in the prion protein (PrP) gene since some mutations are associated with prion disease (1, 2,3). We examined the PrP gene in demented individuals who did not have histopathological changes diagnostic for Alzheimer's disease or other categories of dementia that are pathologically well established (4). The PrP open reading frames of five patients and one control were amplified by PCR to produce 698 base pair products that upon digestion with Pstl and separation by electrophoresis in an 8% polyacrylamide gel had the expected 371 and 327 bp bands of a normal PrP gene in four of the five patients analyzed (Figure 1). However, in one individual, in addition to the expected 327 bp band, there was also a smaller band of equal intensity at approximately 300 bp, indicating a heterozygous deletion in the PrP gene between the 5' primer and the Pstl site. To map the exact position of the deletion in this patient, we cloned the PCR products into plasmids for DNA sequencing. The sequence of both alleles was determined and deposited in GenBank. We found that 24 bp were deleted within the highly conserved glycine-proline-rich octapeptide repeat region of PrP. The deletion removes one of the octapeptide repeats and does not alter the remaining amino acid sequence. No other mutations were found in either allelic sequence. The individual in which we discovered the deletion in the PrP gene had subtle personality changes that heralded the onset of disease at age 58. The dementia progressed to overt confusion by age 68 and death occurred at age 73. Myoclonus and seizures, typical clinical manifestations of prion disease, were not seen in this individual. The family history was unremarkable; both parents and the patient's lone sibling died in their seventh decade of non-neurological illnesses. Microscopic examination of the brain revealed in the frontal and temporal cortex and amygdala occasional senile plaques and rare neurofibrillary tangles that were too few in number to consider a diagnosis of Alzheimer's disease. Vacuolation was virtually limited to the second layer of the prefrontal cortex (Figure 2). The most striking changes were nonspecific neuronal loss and astrocytosis affecting the prefrontal and temporal cortex, hippocampus, amygdala, basal ganglia, thalamus, and substantia nigra very similar to those in demented patients previously described (4). Deletions in the prion protein gene are present in a small percentage of the population. These deletions have not been detected in 101 individuals with atypical dementia (5), but have been found in a Moroccan family (6) and in the HeLa cell line derived from a human cervical carcinoma (7). Recent results
GenBank accession nos. M81929 and M81930
444 Human Molecular Genetics, Vol. 1, No. 6 5. Owen.F., Poulter.M., CollingeJ. et al. (1991) Exp. Neurvl. 112, 240-242. 6. LaplancheJ.-L., ChatelainJ., LaunayJ.-M., Gazengel.C. et al. (1990) Nucleic Acids Res. 18, 6745. 7. Puckett.C, Concannon,R., Casey.C. and Hood.L. (1991) Am. J. Hum. Genet. 49, 320-329. 8. Vnencak-Jones.C.L. and Phillips J.A.IU (1992) Ami. 1. Hum. Genet. 50, 871-872.
Downloaded from http://hmg.oxfordjournals.org/ at University of Glasgow on June 28, 2015
Figure 2. Photomicrograph of a hematoxylin-eosin stained frontal cortex section from the patient with the deletion in the PrP gene. At autopsy, the brains were bisected in the midsagittal plane. One half of the brain was fixed in 10% formalin for 2 - 3 weeks. Formalin-fixed blocks of frontal, temporal, parietal, and occipital cortex, amygdala, hippocampus, basal ganglia, thalamus, cerebellum, midbrain, pons, and medulla were embedded in paraffin, sectioned, and stained with hematoxylin-eosin and Bielschowsky silver stains for neuropathologic analysis. The frontal cortex shows prominent vacuolation in the second layer and astrocytosis in first layer.
Human Molecular Genetics, Vol. 1, No. 6 443—444
Deletion in the prion protein gene in a demented patient J.F.Diedrich, D.S.Knopman1, J.F.List, K.Olson, W.H.Frey II 3 , C.R.Emory3, J.H.Sung12 and A.T.Haase* Department of Microbiology, department of Neurology and laboratory of Medicine and Pathology, University of Minnesota, Minneapolis, MN 55455, and 3Neurdogy Research Laboratories, St Paul-Ramsey Medical Center, St Paul, MN 55101, USA Received April 13, 1992; Revised and Accepted July 20, 1992
* To whom correspondence should be addressed
suggest that the prevalence of these deletions may be as high as 2.5% in the general population (8). Although the deletion in this patient's PrP gene may be coincidental, the dementia, central nervous system vacuolation, and the exclusion of other diagnoses in combination with the PrP gene mutation are certainly compatible with prion disease. While the relationship between the deletion of a single octapeptide repeat in the PrP gene and dementia is unclear, this study calls for further analysis to determine if deletions predispose to neurologic disease. REFERENCES 1. 2. 3. 4.
Owen.F., Lofthouse,R., Crow,T.J. et al. (1989) Lancet I, 51-52. Hsiao.K., Baker.H.R, Crow,T.J. et al. (1989) Nature 338, 342-344. Hsiao,K.K., Scott,M., Foster.D. et al. (1990) Science 250, 1587-1590. Knopman.D.S., Mastri.A.R., Frey.W.H., SungJ.H. and Rustan.T. (1990) Neurology 40, 251-256.
bp
371 -
327-298
Figure 1. PrP coding sequences amplified by PCR and digested with Pstl Tissues were collected by the St Paul Ramsey-University of Minnesota Brain Bank between 1980 and 1986. A group of demented patients were identified that did not have histopathological changes diagnostic for Alzheimer's disease or other categories of dementia that are pathologically well established (4). At autopsy, the brains were bisected in the midsagittal plane. One half of the brain was frozen as 10 coronal sections. Genomic DNA was extracted from frozen prefrontal cortex using standard techniques. In the case of the nondemented control, genomic DNA was extracted from peripheral blood. The PrP coding sequences were amplified using the PCR primers ATGCTGGTTCTCTTTGTGCXrCACATGGAGTGACCT and ACAGGTGGAGAGGAGAAGAGGACCATGCTCGATCC. The 698 bp PCR product was gel-purified, digested with Pstl, electrophoresed in an 8% polyacrylamide gel, and stained with ethidium bromide. The lengths of the DNA markers (M) in base pairs (bp) are shown in the right margin, and the lengths of the two expected DNA bands are shown in the left margin. The arrow indicates the additional band at approximately 300 bp in one individual. Lanes 1 through 5, demented patients; lane 6, nondemented control.
Downloaded from http://hmg.oxfordjournals.org/ at University of Glasgow on June 28, 2015
It is important to characterize mutations in the prion protein (PrP) gene since some mutations are associated with prion disease (1, 2,3). We examined the PrP gene in demented individuals who did not have histopathological changes diagnostic for Alzheimer's disease or other categories of dementia that are pathologically well established (4). The PrP open reading frames of five patients and one control were amplified by PCR to produce 698 base pair products that upon digestion with Pstl and separation by electrophoresis in an 8% polyacrylamide gel had the expected 371 and 327 bp bands of a normal PrP gene in four of the five patients analyzed (Figure 1). However, in one individual, in addition to the expected 327 bp band, there was also a smaller band of equal intensity at approximately 300 bp, indicating a heterozygous deletion in the PrP gene between the 5' primer and the Pstl site. To map the exact position of the deletion in this patient, we cloned the PCR products into plasmids for DNA sequencing. The sequence of both alleles was determined and deposited in GenBank. We found that 24 bp were deleted within the highly conserved glycine-proline-rich octapeptide repeat region of PrP. The deletion removes one of the octapeptide repeats and does not alter the remaining amino acid sequence. No other mutations were found in either allelic sequence. The individual in which we discovered the deletion in the PrP gene had subtle personality changes that heralded the onset of disease at age 58. The dementia progressed to overt confusion by age 68 and death occurred at age 73. Myoclonus and seizures, typical clinical manifestations of prion disease, were not seen in this individual. The family history was unremarkable; both parents and the patient's lone sibling died in their seventh decade of non-neurological illnesses. Microscopic examination of the brain revealed in the frontal and temporal cortex and amygdala occasional senile plaques and rare neurofibrillary tangles that were too few in number to consider a diagnosis of Alzheimer's disease. Vacuolation was virtually limited to the second layer of the prefrontal cortex (Figure 2). The most striking changes were nonspecific neuronal loss and astrocytosis affecting the prefrontal and temporal cortex, hippocampus, amygdala, basal ganglia, thalamus, and substantia nigra very similar to those in demented patients previously described (4). Deletions in the prion protein gene are present in a small percentage of the population. These deletions have not been detected in 101 individuals with atypical dementia (5), but have been found in a Moroccan family (6) and in the HeLa cell line derived from a human cervical carcinoma (7). Recent results
GenBank accession nos. M81929 and M81930
444 Human Molecular Genetics, Vol. 1, No. 6 5. Owen.F., Poulter.M., CollingeJ. et al. (1991) Exp. Neurvl. 112, 240-242. 6. LaplancheJ.-L., ChatelainJ., LaunayJ.-M., Gazengel.C. et al. (1990) Nucleic Acids Res. 18, 6745. 7. Puckett.C, Concannon,R., Casey.C. and Hood.L. (1991) Am. J. Hum. Genet. 49, 320-329. 8. Vnencak-Jones.C.L. and Phillips J.A.IU (1992) Ami. 1. Hum. Genet. 50, 871-872.
Downloaded from http://hmg.oxfordjournals.org/ at University of Glasgow on June 28, 2015
Figure 2. Photomicrograph of a hematoxylin-eosin stained frontal cortex section from the patient with the deletion in the PrP gene. At autopsy, the brains were bisected in the midsagittal plane. One half of the brain was fixed in 10% formalin for 2 - 3 weeks. Formalin-fixed blocks of frontal, temporal, parietal, and occipital cortex, amygdala, hippocampus, basal ganglia, thalamus, cerebellum, midbrain, pons, and medulla were embedded in paraffin, sectioned, and stained with hematoxylin-eosin and Bielschowsky silver stains for neuropathologic analysis. The frontal cortex shows prominent vacuolation in the second layer and astrocytosis in first layer.
