Mutations
MAPT S305N
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Overview
Pathogenicity: Frontotemporal Dementia : Pathogenic
Clinical
Phenotype: Frontotemporal Dementia
Position: (GRCh38/hg38):Chr17:46010401 G>A
Position: (GRCh37/hg19):Chr17:44087767 G>A
dbSNP ID: rs63751165
Coding/Non-Coding: Coding
DNA
Change: Substitution
Expected RNA
Consequence: Substitution
Expected Protein
Consequence: Missense
Codon
Change: AGT to AAT
Reference
Isoform: Tau Isoform Tau-F (441 aa)
Genomic
Region: Exon 10
Findings
This mutation was first reported in a Japanese family affected by early onset frontotemporal dementia. The reported pedigree shows three affected individuals over two generations, with a mean onset age of 35 years. The three individuals presented first with personality changes, followed by impaired cognition and memory as well as disorientation. They later became mute. One of the three suffered from mild parkinsonism. The mutation was detected in the proband but was absent in his healthy father and maternal uncle, suggesting segregation with disease. No mutations were detected in exons 4-13 of PSEN1 or PSEN2. The S305N mutation was absent in 90 Japanese controls (Iijima et al., 1999).
In another S305N kindred, thought to be unrelated to the one described above, two mutation-carrying brothers had a clinical/pathological phenotype resembling Pick’s disease, a type of frontotemporal dementia. They initially presented with inertia and forgetfulness and had a family history consistent with familial FTD. Their paternal grandmother was known for eccentric behavior and their father died at age 44 of a syndrome characterized by behavioral changes, notably aggression. The mutation appears to segregate with disease in this family: It was present in the two affected brothers, but absent in their unaffected mother (Kobayashi et al., 2002; Kobayashi et al., 2003).
Neuropathology
Postmortem examination of the first proband revealed numerous neurofibrillary tangles with an unusual morphology and distribution. Rather than flame-shaped, the tangles appeared as ring-shaped structures frequently enveloping neuronal nuclei, especially in the frontal, temporal, insular, and postcentral cortices, as well as in dentate gyrus. Tau-positive inclusions were observed in both neurons and glia. Coiled bodies and neuropil threads resembling those seen in corticobasal degeneration were observed, and electron microscopy showed straight tubules (Iijima et al., 1999).
Neuropathological data were also available for the second kindred. MRI showed atrophy of the right temporal lobe, including the hippocampal formation. Atrophy was severe with a "knife-edge" appearance. Pick body-like inclusions were observed, including astrocytic inclusions in the hippocampus, amygdala and thalamus. Similar to the observations in the previously described kindred, electron microscopy showed straight filaments in the inclusion bodies (Kobayashi et al., 2003).
Biological Effect
In silico analyses predicted this mutation diminishes cathepsin cleavage which was confirmed in vitro using protease assays (Sampognaro et al., 2023). Consistent with these findings, the lysosomal degradation of mutant tau in neuronal-like SH-SY5Y cells was reduced.
Last Updated: 16 Jun 2023
References
Paper Citations
- Iijima M, Tabira T, Poorkaj P, Schellenberg GD, Trojanowski JQ, Lee VM, Schmidt ML, Takahashi K, Nabika T, Matsumoto T, Yamashita Y, Yoshioka S, Ishino H. A distinct familial presenile dementia with a novel missense mutation in the tau gene. Neuroreport. 1999 Feb 25;10(3):497-501. PubMed.
- Kobayashi K, Hayashi M, Kidani T, Nakano H, Miyazu K, Ujike H, Kuroda S, Koshino Y. Pick's disease in 2 brothers with S305N mutation: note in supplement to an earlier communication. Clin Neuropathol. 2002 Jul-Aug;21(4):191-3. PubMed.
- Kobayashi K, Kidani T, Ujike H, Hayashi M, Ishihara T, Miyazu K, Kuroda S, Koshino Y. Another phenotype of frontotemporal dementia and parkinsonism linked to chromosome-17 (FTDP-17) with a missense mutation of S305N closely resembling Pick's disease. J Neurol. 2003 Aug;250(8):990-2. PubMed.
- Sampognaro PJ, Arya S, Knudsen GM, Gunderson EL, Sandoval-Perez A, Hodul M, Bowles K, Craik CS, Jacobson MP, Kao AW. Mutations in α-synuclein, TDP-43 and tau prolong protein half-life through diminished degradation by lysosomal proteases. Mol Neurodegener. 2023 May 2;18(1):29. PubMed. Correction.
Further Reading
Papers
- Kobayashi K, Hayashi M, Fukutani Y, Miyazu K, Shiozawa M, Muramori F, Aoki T, Koshino Y. KP1 expression of ghost Pick bodies, amyloid P-positive astrocytes and selective nigral degeneration in early onset Picks disease. Clin Neuropathol. 1999 Sep-Oct;18(5):240-9. PubMed.
- Poorkaj P, Grossman M, Steinbart E, Payami H, Sadovnick A, Nochlin D, Tabira T, Trojanowski JQ, Borson S, Galasko D, Reich S, Quinn B, Schellenberg G, Bird TD. Frequency of tau gene mutations in familial and sporadic cases of non-Alzheimer dementia. Arch Neurol. 2001 Mar;58(3):383-7. PubMed.
- Kobayashi K, Hayashi M, Kidani T, Ujike H, Iijima M, Ishihara T, Nakano H, Sugimori K, Shimazaki M, Kuroda S, Koshino Y. Pick's disease pathology of a missense mutation of S305N of frontotemporal dementia and parkinsonism linked to chromosome 17: another phenotype of S305N. Dement Geriatr Cogn Disord. 2004;17(4):293-7. PubMed.
- Boeve BF, Tremont-Lukats IW, Waclawik AJ, Murrell JR, Hermann B, Jack CR Jr, Shiung MM, Smith GE, Nair AR, Lindor N, Koppikar V, Ghetti B. Longitudinal characterization of two siblings with frontotemporal dementia and parkinsonism linked to chromosome 17 associated with the S305N tau mutation. Brain. 2005 Apr;128(Pt 4):752-72. Epub 2004 Dec 22 PubMed.
Learn More
Protein Diagram
Primary Papers
- Iijima M, Tabira T, Poorkaj P, Schellenberg GD, Trojanowski JQ, Lee VM, Schmidt ML, Takahashi K, Nabika T, Matsumoto T, Yamashita Y, Yoshioka S, Ishino H. A distinct familial presenile dementia with a novel missense mutation in the tau gene. Neuroreport. 1999 Feb 25;10(3):497-501. PubMed.
- Kobayashi K, Hayashi M, Kidani T, Nakano H, Miyazu K, Ujike H, Kuroda S, Koshino Y. Pick's disease in 2 brothers with S305N mutation: note in supplement to an earlier communication. Clin Neuropathol. 2002 Jul-Aug;21(4):191-3. PubMed.
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