First Appraisal of Brain Pathology Owing to A30P Mutant Alpha-Synuclein

Abstract

Familial Parkinson disease (PD) due to the A30P mutation in the SNCA gene encoding alpha-synuclein is clinically associated with PD symptoms. In this first pathoanatomical study of the brain of an A30P mutation carrier, we observed neuronal loss in the substantia nigra, locus coeruleus, and dorsal motor vagal nucleus, as well as widespread occurrence of alpha-synuclein immunopositive Lewy bodies, Lewy neurites, and glial aggregates. Alpha-synuclein aggregates ultrastructurally resembled Lewy bodies, and biochemical analyses disclosed a significant load of insoluble alpha-synuclein, indicating neuropathological similarities between A30P disease patients and idiopathic PD, with a more severe neuropathology in A30P carriers.

Full text

First Appraisal of Brain
Pathology Owing to A30P
Mutant Alpha-Synuclein
Kay Seidel, PhD,
1
Ludger Scho¨ ls, MD,
2
Silke Nuber, PhD,
3
Elisabeth Petrasch-Parwez, MD,
4
Kristin Gierga, MD,
5
Zbigniew Wszolek, MD,
6
Dennis Dickson, MD,
7
Wei P. Gai, PhD, MD,
8
Antje Bornemann, MD,
9
Olaf Riess, MD,
3
Abdelhaq Rami, PhD,
10
Wilfried F. A. den Dunnen, MD,
11
Thomas Deller, MD,
1
Udo Ru¨b, MD,
1
and
Rejko Kru¨ ger, MD
2
Familial Parkinson disease (PD) due to the A30P
mutation in the SNCA gene encoding alpha-
synuclein is clinically associated with PD symp-
toms. In this first pathoanatomical study of the
brain of an A30P mutation carrier, we observed
neuronal loss in the substantia nigra, locus coer-
uleus, and dorsal motor vagal nucleus, as well as
widespread occurrence of alpha-synuclein immu-
nopositive Lewy bodies, Lewy neurites, and glial
aggregates. Alpha-synuclein aggregates ultra-
structurally resembled Lewy bodies, and biochem-
ical analyses disclosed a significant load of insol-
uble alpha-synuclein, indicating neuropathological
similarities between A30P disease patients and id-
iopathic PD, with a more severe neuropathology
in A30P carriers.
ANN NEUROL 2010;67:684–689
The identification of the SNCA gene on chromosome
4q21-23 encoding alpha-synuclein as the first gene
responsible for autosomal dominantly inherited Parkinson
disease (PD) and the subsequent characterization of 3
point mutations in this gene—A53T, E46K, and A30P—
revealed a close clinical relationship between familial PD
and idiopathic PD (IPD).
1–3
Together with familial forms
of PD due to multiplications of the SNCA gene, these 3
point mutations have attracted neuropathological interest,
because of hopes that insights into the pathomechanisms
of inherited PD could be helpful to unravel the unknown
pathogenesis of the frequent synucleinopathy IPD.
4
Contrasting the close clinical similarities, the neuro-
pathological relationship between familial PD caused by
mutations in the alpha-synuclein–encoding SNCA gene
and IPD is not well understood, because neuropatholog-
ical data on familial PD are limited.
2,5,6
To gain more
insight into the neuropathology of familial PD, we per-
formed the first pathoanatomical study of the brain of an
A30P mutation carrier in the SNCA gene.
Subjects and Methods
The 69-year-old male index patient from the German A30P
family received diagnosis of PD at the age of 54 years and was
successfully treated with L-dopa for the next 2 years.
7
The clin-
ical course until age 65 years included occurrences of L-dopa–
related complications (ie, hallucinations). With further disease
progression, the patient lost independence in all activities of
daily living and was unable to walk without assistance. During
the last years prior to his death, the patient also suffered from a
progressive cognitive decline. At the age of 69 years, he became
mutistic, dysphagic, and bedridden, and was kept alive by per-
cutaneous endoscopic gastrostomy (PEG). He died of respiratory
failure in a poor state of general health.
The brains of the A30P patient and 6 control individuals
(1 female, 5 males; mean age at death 60.7 ⫾12.8 years) were
examined in accordance with the Ethics Committee guidelines
of the Faculty of Medicine at Goethe University of Frankfurt
am Main. The brain of the A30P patient displayed a severe de-
pigmentation of the substantia nigra, as well as a slight atrophy
of the frontal, temporal, and parietal cerebral lobes (Fig 1B).
After fixation of the brains by immersion in 4% buffered form-
aldehyde solution, the cerebral, cerebellar, and brainstem tissue
blocks of the A30P patient and of 5 control cases were embed-
ded in polyethylene glycol (PEG 1000, Merck, Darmstadt, Ger-
many). For detailed tissue processing and staining procedures,
see the Supplemental Material.
The severity of neuronal loss and the frequency of alpha-
synuclein–immunopositive Lewy bodies (LBs), Lewy neurites
(LNs), and glial inclusions in the brain of the A30P index pa-
From the
1
Institute of Clinical Neuroanatomy, Dr Senckenberg Anat-
omy, Goethe University, Frankfurt am Main, Germany;
2
Center of
Neurology and Hertie-Institute for Clinical Brain Research, University
of Tu¨ bingen, Tu¨ bingen, Germany;
3
Department of Medical Genetics,
University of Tu¨ bingen, Tu¨ bingen, Germany;
4
Neuroanatomy and Mo-
lecular Brain Research, Ruhr-University Bochum, Bochum, Germany;
5
Department of Neuropathology, Heinrich-Heine-University, Du¨ ssel-
dorf, Germany;
6
Department of Neurology, Mayo Clinic, Jacksonville,
FL;
7
Neuropathology Laboratory, Mayo Clinic, Jacksonville, FL;
8
De-
partment of Human Physiology, Flinders University School of Medi-
cine, Bedford Park, Australia;
9
Institute of Brain Research, University of
Tu¨ bingen, Tu¨ bingen, Germany;
10
Institute for Cellular and Molecular
Anatomy, Goethe University, Frankfurt am Main, Germany; and
11
De-
partment of Pathology and Medical Biology, University Medical Cen-
ter Groningen, University of Groningen, Groningen, the Netherlands.
Address correspondence to Dr Ru¨ b, Institute of Clinical Neuroanat-
omy, Dr. Senckenberg Anatomy, Goethe University, Theodor-Stern-Kai
7, D-60590 Frankfurt/Main, Germany; E-mail: Drueb@gmx.de or Dr
Kru¨ ger, Center of Neurology and Hertie-Insitute for Clinical Brain Re-
search, University of Tu¨ bingen, Hoppe-Seyler-Str. 3, 72076 Tu¨ bingen,
Germany; E-mail: rejko.krueger@uni-tuebingen.de
Received Jun 30, 2009, and in revised form Dec 10. Accepted for
publication Dec 22, 2009.
Published online in Wiley InterScience (www.interscience.wiley.com).
DOI: 10.1002/ana.21966
Additional Supporting Information may be found in the online version
of this article.
ANNALS of Neurology
684 Volume 67, No. 5

tient were semiquantitatively assessed (not discernible, ⫺; slight,
⫹; marked, ⫹⫹; severe, ⫹⫹⫹; Supplementary Tables 1–5).
Subcellular fractionation of frontal or entorhinal cortex
tissue from the A30P patient, 1 patient from a Greek-American
kindred carrying the A53T mutation in the SNCA gene,
8
1 pa-
tient with dementia with Lewy bodies (DLB), 2 IPD patients,
and 2 control individuals (Supplementary Table 6) was per-
formed as described previously.
9,10
Western blots using 3 differ-
ent antibodies against alpha-synuclein (N-terminus: PA1-38705,
Affinity Bioreagents, Golden, CO; NAC domain: Mc42, Trans-
labs, UK; C-terminus:15G7; AG Scientific, San Diego, CA)
were reproduced 3 times with similar results, with each sample
loaded at least 2 times on different blots.
Electron microscopy was performed to elucidate the ultra-
structure of neuronal alpha-synuclein aggregates in the substan-
tia nigra, basal nucleus of Meynert, and dorsal motor vagal nu-
cleus (DMV) of the A30P patient and 1 patient with IPD as
control (female; age at death, 76 years; disease duration, 26
years; Braak stage 5) as described previously.
11
Results
Investigation of pigment-Nissl stained tissue sections re-
vealed neuronal loss in the pars compacta of the substan-
tia nigra (see Fig 1D, E), locus coeruleus, and DMV (see
Fig 1F, G).
LBs and LB-like inclusions occurred as spherical,
reniform, or globose neuronal inclusions with smooth sur-
faces (Fig 2A). LNs had a club-or corkscrew-shaped ap-
pearance, or were short and stubby or slender, elongated,
and thread-like (see Fig 2A). Alpha-synuclein–immu-
nopositive LBs were present in all areas of the cerebral
cortex (neocortex: predominantly in layers V and VI;
ento-and transentorhinal regions: predominantly in layers
II, III, V, and VI; subiculum, presubiculum, hippocampal
CA1, CA2, and CA3 sectors: predominantly in pyramidal
layers) (Supplementary Fig 1A, B), in all nuclei of the
basal forebrain, basal ganglia, amygdala, and hypothala-
Š
FIGURE: 1 Macroscopic brain aspects in A30P and A30P
mutation-related nerve cell loss. (A) Lateral aspect of the
left cerebral hemisphere of a 53-year-old male individual
without a prior medical history of neurological or psychi-
atric disease. (B) Lateral aspect of the left cerebral hemi-
sphere from the A30P index patient. Note the widened
sulci of the frontal (arrowheads), temporal (asterisk), and
parietal lobes (arrow). (C) Pedigree of the German A30P
family indicating the deceased index patient (black arrow;
filled black symbols: affected family members according to
the United Kingdom Parkinson’s Disease Brain Bank crite-
ria; filled gray symbols: individuals displaying subtle extra-
pyramidal symptoms; circles: females; squares: males;
oblique slashes: deceased individuals; open symbols:
healthy family members). (D) Frontal section through the
rostral midbrain of a typical 59-year-old male control case
with the dorsal portion of the substantia nigra (SN). (E)
Severely degenerated SN of the A30P index patient. (F)
Horizontal section through the mid portion of the medulla
oblongata of an 84-year-old male control case showing the
dorsal motor vagal nucleus (DMV). (G) Markedly degener-
ated DMV of the A30P index patient. Arrows point to
surviving nerve cells. A–D: aldehyde fuchsin-Darrow red
staining, 100
␮
m percutaneous endoscopic gastrostomy
sections. I ⴝfirst generation; II ⴝsecond generation; III ⴝ
third generation; IV ⴝfourth generation; V ⴝfifth gener-
ation; PP ⴝperipeduncular nucleus; RD ⴝred nucleus;
CP ⴝcerebral peduncle; SOL ⴝsolitary tract; IC ⴝinter-
calate nucleus; XII ⴝhypoglossal nucleus.
Seidel et al: A30P Family Pathoanatomy
May, 2010 685

mus (see Supplementary Fig 1C, D), in select regions of
the thalamus (see Supplementary Fig 1E–H), subthalamus
(Supplementary Fig 2A), and brainstem (see Supplemen-
tary Fig 2B–F), and in the cerebellum.
In the thalamus, basal nucleus of Meynert, substan-
tia nigra, DMV, gigantocellular reticular nucleus, raphes
magnus nucleus, and intermediate reticular zone, we ob-
served alpha-synuclein–immunopositive neurons without
FIGURE: 2 Alpha-synuclein immunocytochemical and electron microscopic findings in the A30P index patient. (A) Lewy
bodies (LBs) (large arrows) and Lewy neurites (arrowheads) in the dorsal motor vagal nucleus. Small arrows point to coiled
bodies. (B) Gleason score glial fibrillary acidic protein (GFAP)-immunopositive astrocytes in the transentorhinal cortex con-
taining alpha-synuclein immunopositive deposits (arrowheads). (C) Substantia nigra: Typical coiled-up alpha-synuclein immu-
nopositive oligodendroglial inclusion (brown) surrounding the nucleus (blue) of the affected oligodendrocyte. (D) The dorsal
motor vagal nucleus of the A30P patient exhibits various LBs (arrows) with a dark inner core and a ring-like light outer zone.
(E, F) Electron micrograph of the LB in the lower left corner of D (asterisk). The LB shows a dense granular core (Co),
surrounded by a lighter outer zone (OZ), which contains loosely arranged filaments (F). (G, H) Electron micrograph of an LB
found in an idiopathic Parkinson disease case. Note the high structural similarity of the LBs from both cases. (A) Anti–
alpha-synuclein immunocytochemistry; (B) anti-GFAP (3,3ⴕ-diaminobenzidine [DAB], brown)/anti–alpha-synuclein (SK4700,
blue-gray) double immunostaining; (C) antitransferrin (SK4700, blue-gray)/anti–alpha-synuclein (DAB, brown) double immu-
nostaining; (A–C) 100
␮
m percutaneous endoscopic gastrostomy sections; (D) toluidine blue-stained semithin section, 0.75
␮
m;
(E–H) uranyl acetate and lead citrate contrasted ultrathin section, 100nm).
ANNALS of Neurology
686 Volume 67, No. 5

LBs or LNs. These neurons, however, were characterized
by the presence of fine alpha-synuclein–immunopositive,
slightly brownish, and loosely scattered cytoplasmic gran-
ules sparing the nucleus and often extending into the pro-
cesses of nerve cells. In addition, alpha-synuclein immu-
nopositivity and/or LB-like inclusions were observed in
central nervous white matter components (see Supple-
mentary Fig 2E–H).
Alpha-synuclein–immunopositive coiled bodies (see
Fig 2A, C; Supplementary Fig 2A, B) and glial fibrillary
acidic protein-immunopositive astrocytes were present in
all gray and white matter components of the telencepha-
lon, diencephalon, brainstem, and cerebellum of the
A30P patient. Anti–alpha-synuclein/antitransferrin double
immunostaining confirmed the purely oligodendroglial lo-
calization of the coiled bodies, and AT8 and PHF-1 im-
munostaining excluded their tau immunoreactivity (see
Fig 2C). Alpha-synuclein–immunopositive and tau-
negative astrocytes (see Fig 2B) occurred in all nuclei of
the amygdala and the septum, striatum, claustrum, select
thalamic nuclei (ie, central lateral nucleus, limitans-
suprageniculate complex), temporal neocortex, and ento-
and transentorhinal regions. No colocalization of tau with
alpha-synuclein was observed in neurons and oligoden-
drocytes of the dorsal raphe nucleus and the intermediate
reticular zone (Supplementary Fig 3).
The Alzheimer disease (AD)-related cortical cy-
toskeletal pathology as assessed by AT8 and PHF-1 im-
munostaining corresponded to Braak stage II, and the
brain ␤-amyloidosis to phase 1 of the schema proposed by
Thal and colleagues.
12,13
Ultrastructural studies confirmed neuronal loss in
the substantia nigra and DMV nucleus. The majority of
remaining nigral neurons underwent dark cell degenera-
tion. Several surviving nigral neurons displayed round so-
matic inclusions with a denser center and a lighter outer
zone as a correlate of LBs. In the DMV nucleus, LBs were
detected with a dark dense core (see Fig 2D) and a broad
lighter outer zone reflecting the classical brainstem type of
LB.
14
They were frequently localized in the cytoplasm of
nerve cells, but also occurred in the neuropil, suggesting
dendritic or axonal localization. Electron microscopy re-
FIGURE: 3 Western blots of sequentially extracted alpha-
synuclein. (A) Frontal cortex tissues from 2 healthy control
individuals, 1 patient with dementia with Lewy bodies
(DLB), 2 idiopathic Parkinson disease (IPD) patients (Braak
stage 3 and 5), the A30P patient, and a patient carrying
the A53T mutation were sequentially extracted with Tris-
HCl (TBS) and urea (U; insoluble fraction) followed by im-
munoblotting with antibodies specific to the epitopes indi-
cated in A. The IPD patient with advanced Braak stage 5,
the DLB patient, and both mutation carriers revealed in-
soluble monomeric (
␣
-SYN)
1
and oligomeric alpha-synuclein
(
␣
-SYN)
n
species in the urea fraction, which were most pro-
nounced in the A30P patient (asterisks). (B) Sequential pro-
tein extraction of the entorhinal and frontal cortices of the
A30P patient and an A53T patient revealed a strong alpha-
synuclein signal in the urea-soluble fractions of the A30P
mutation carrier (asterisks). (C) Schematic representation of
the human alpha-synuclein protein and epitopes of the an-
tibodies used in this study. T/T; Triton X-100-soluble, mem-
brane bound fraction.
‹
Seidel et al: A30P Family Pathoanatomy
May, 2010 687

vealed a dense dark granular center and a ring-like outer
zone with abundant fibrils (see Fig 2E, F), similar to the
ultrastructural characteristics of LBs from an IPD patient
(Braak stage 5; see Fig 2G, H).
Biochemical sequential extraction of alpha-synuclein
of frontal cortex of controls, DLB patients, IPD patients
(Braak stage 3 and stage 5), the A30P patient, and an
A53T patient revealed soluble monomeric alpha-synuclein
in all samples (Tris-HCl; Fig. 3A). The presence of mo-
nomeric and oligomeric alpha-synuclein species in the
urea fraction was not observed in controls and disclosed
insolubility of alpha-synuclein that was most prominent
in the A30P case and DLB patient (see Fig 3A). A30P
alpha-synuclein insolubility was prominent in both the
entorhinal and frontal cortex of the A30P patient substan-
tiating immunohistochemically determined LB load in
these 2 brain areas (see Fig 3B).
Discussion
Our study provides first insights into the pathoanatomy
of familial PD caused by the A30P mutation in the SNCA
gene and demonstrates a widespread central nervous oc-
currence of alpha-synuclein–immunopositive inclusions
and the advantage of investigations of complete tissue se-
ries for the identification of more subtle pathological al-
terations.
15,16
Application of sensitive immunostaining methods
revealed tau-immunoreactive cortical cytoskeletal pathol-
ogy in the index patient. Because no additional tau-
positive neuronal and glial inclusions associated with
other known human tauopathies were observed, the cor-
tical tau pathology most likely corresponded to the early
Braak AD stage II.
12
In addition, alpha-synuclein immu-
nocytochemistry in the A30P patient did not reveal fea-
tures of neuronal inclusions or the distribution pattern of
alpha-synuclein–immunopositive oligodendroglial inclu-
sions typical for multiple system atrophy.
15
As in IPD, the A30P patient’s brain showed neuro-
nal loss in the substantia nigra, DMV, and locus coer-
uleus and displayed recognized neuronal pathologies (ie,
LBs, LNs, and LB-like inclusions) in brain structures typ-
ically affected in IPD (eg, neo-and allocortex, thalamus,
cerebellum, substantia nigra, pedunculopontine nucleus,
DMV), as well as in brainstem nuclei and central nervous
fiber tracts that are not or are only less severely affected in
IPD (eg, rostral interstitial nucleus of the medial longitu-
dinal fascicle, reticulotegmental nucleus of the pons, me-
dial vestibular nucleus, spinocerebellar tracts, and cerebel-
lar peduncles).
17,18
In addition, as in IPD, alpha-
synuclein–immunopositive astroglial and oligodendroglial
inclusions were present in the A30P patient.
19
Among the currently known brain pathologies re-
ported in familial PD forms caused by mutations or mul-
tiplications in the SNCA gene, the brain pathology of the
A30P index patient most closely resembled the brain al-
terations observed in IPD individuals.
2,5,6,20
Neuropatho-
logical discrepancies that strengthen the pathogenic role
of A30P mutant alpha-synuclein and may indicate differ-
ent etiopathogenic mechanisms included: (1) substantial
and more severe load of alpha-synuclein aggregates in the
cerebellum and precerebellar and occulomotor brainstem
nuclei than in IPD; and (2) presence of more glial aggre-
gates, named coiled bodies, in the A30P brain than in
IPD. The presence of concurrent tau pathology in A53T
mutation carriers or the accumulation of alpha-synuclein
and tau within the same neuronal aggregates in carriers of
alpha-synuclein multiplications underscore important dis-
crepancies between IPD patients and the A30P mutation
carrier studied here.
5,20
A pathological relationship between the alpha-
synuclein pathology of A30P and IPD is also supported
(1) by our ultrastructural analyses of LBs in the A30P
mutation carrier in comparison to an IPD patient, and
(2) by our biochemical findings, which showed insolubil-
ity of alpha-synuclein in the A30P patient and in IPD
patients. This insolubility reflects a substantial aggregate-
forming capacity of A30P mutant alpha-synuclein and
contrasts with previous in vitro observations on fibril for-
mation of different mutant alpha-synuclein species.
21
In summary, the pathological similarities between
the A30P patient and IPD strongly support the view that
familial PD caused by the A30P mutation in the SNCA
gene not only is closely related to IPD clinically, but also
pathologically. Although additional postmortem A30P
studies are required to ultimately define this neuropatho-
logical relationship, our study provides major implications
for the validation of transgenic animal models for PD.
Acknowledgment
This study was supported by the Deutsche Forschungsge-
meinschaft (RU 1215/1-2, KR2119/3-1) and the Federal
Ministry for Education and Research (01GS01834, R.K.
and O.R.).
We thank the A30P family for their continued sup-
port and interest in this project; P. Davies for the dona-
tion of the PHF-1 antibody; M. Babl, B. Meseck-
Selchow, M. Bouzrou for processing of tissue sections and
immunocytochemistry; M. Lo¨bbecke-Schuhmacher for
electron microscopy; and M. Hu¨tten for secretarial assis-
tance.
ANNALS of Neurology
688 Volume 67, No. 5

Potential Conflicts of Interest
Udo Ru¨b is the Executive Editor of Neuropathology and
Applied Neuropathology.
References
1. Polymeropoulos MH, Lavedan C, Leroy E, et al. Mutation in the
alpha-synuclein gene identified in families with Parkinson’s dis-
ease. Science 1997;276:2045–2047.
2. Zarranz JJ, Alegre J, Gomez-Estaban JC, et al. The new muta-
tion, E46K, of alpha-synuclein causes Parkinson and Lewy body
dementia. Ann Neurol 2004;55:164–173.
3. Kru¨ ger R, Kuhn W, Mu¨ ller T, et al. Ala30Pro mutation in the
gene encoding alpha-synuclein in Parkinson’s disease. Nat Genet
1998;18:106–108.
4. Schiesling C, Kieper N, Seidel K, Kru¨ ger R. Familial PD-genetics,
clinical phenotype and neuropathology in relation to the com-
mon sporadic form of the disease. Neuropathol Appl Neurobiol
2008;34:255–271.
5. Duda JE, Giasson BI, Mabon ME, et al. Concurrence of alpha-
synuclein and tau brain pathology in the Contursi kindred. Acta
Neuropathol 2002;104:7–11.
6. Markopoulou K, Dickson DW, McComb RD, et al. Clinical, neu-
ropathological and genotypic variability in SNCA A53T familial
Parkinson’s disease: variability in familial Parkinson’s disease.
Acta Neuropathol 2008;116:25–35.
7. Kru¨ ger R, Kuhn W, Leenders KL, et al. Familial parkinsonism with
synuclein pathology: clinical and PET studies of A30P mutation
carriers. Neurology 2001;56:1355–1362.
8. Markopoulou K, Wszolek ZK, Pfeiffer RF. A Greek-American kin-
dred with autosomal dominant, levodopa-responsive parkinson-
ism and anticipation. Ann Neurol 1995;38:373–378.
9. Braak H, Del Tredici K, Ru¨ b U, et al. Staging of brain pathology
related to sporadic Parkinson’s disease. Acta Neuropathol 2003;
24:197–211.
10. Tofaris GK, Razzaq A, Ghetti B, et al. Ubiquitination of alpha-
synuclein in Lewy bodies is a pathological event not associated
with impairment of proteasome function. J Biol Chem 2003;278:
44405–44411.
11. Petrasch-Parwez A, Nguyen HP, Lo¨bbecke-Schumacher M, et al.
Cellular and subcellular localization of Huntingtin aggregates in
the brain of a rat transgenic for Huntington disease. J Comp
Neurol 2007;501:716–730.
12. Braak H, Braak E. Neuropathological staging of Alzheimer-related
changes. Acta Neuropathol 1991;82:239–259.
13. Thal DR, Ru¨b U, Orantes M, Braak H. Phases of Abeta-deposition
in the human brain and its relevance for the development of AD.
Neurology 2002;58:1791–1800.
14. Kosaka K. Lewy bodies in cerebral cortex, report of three cases.
Acta Neuropathol 1978;42:127–134.
15. Braak H, Ru¨b U, Del Tredici K. Involvement of precerebellar nu-
clei in multiple system atrophy. Neuropathol Appl Neurobiol
2003;29:60–76.
16. Ru¨b U, Brunt ER, Del Turco D, et al. Guidelines for the patho-
anatomical examination of the lower brain stem in ingestive and
swallowing disorders and its application to a dysphagic spino-
cerebellar ataxia type 3 patient. Neuropathol Appl Neurobiol
2003;29:1–13.
17. Braak H, Del Tredici K. Neuroanatomy and pathology of sporadic
Parkinson’s disease. Berlin, Heidelberg: Springer, 2009.
18. Ru¨b U, Del Tredici K, Schultz C, et al. Parkinson’s disease: the
thalamic components of the limbic loop are severely impaired by
alpha-synuclein immunopositive inclusion body pathology. Neu-
robiol Aging 2002;23:245–254.
19. Wakabayashi K, Hayashi S, Yoshimoto M, et al. NACP/alpha-
synuclein-positive filamentous inclusions in astrocytes and oligo-
dendrocytes of Parkinson’s disease brains. Acta Neuropathol
2000;99:14–20.
20. Gwinn-Hardy K, Mehta ND, Farrer M, et al. Distinctive neuropa-
thology revealed by alpha-synuclein antibodies in hereditary par-
kinsonism and dementia linked to chromosome 4p. Acta Neuro-
pathol 2000;99:663–672.
21. Conway KA, Harper JD, Lansbury PT. Accelerated in vitro fibril
formation by a mutant alpha-synuclein linked to early-onset Par-
kinson disease. Nat Med 1998;4:1318–1320.
Endogenous Neurosteroid
Synthesis Modulates Seizure
Frequency
Courtney Lawrence, Brandon Scott Martin,
Chengsan Sun, John Williamson, and
Jaideep Kapur, PhD
Inhibitory neurosteroids, molecules generated in glia
from circulating steroid hormones and de novo from
cholesterol, keep seizures in check in epileptic ani-
mals. They can enhance inhibitory transmission medi-
ated by gamma-aminobutyric acid receptors and have
anticonvulsant action.
ANN NEUROL 2010;67:689–693
Many pathological changes in the epileptic brain in-
crease the propensity for seizures; however, certain
biological mechanisms and molecules appear to keep sei-
zures in check in epileptic animals. Inhibitory neuros-
teroids, molecules generated in glia from circulating ste-
roid hormones and de novo from cholesterol, are
candidate molecules for checking seizures because they
can enhance inhibitory transmission mediated by gamma-
aminobutyric acid (GABA)
A
receptors and have anticon-
vulsant action.
1
Neurosteroids modulate both synaptic
and tonic inhibition mediated by GABA
A
receptors.
2,3
Anticonvulsant action of naturally occurring neuro-
steroids was demonstrated soon after their GABA
A
recep-
tor action was found.
4
The potency of anticonvulsant ac-
From the Department of Neurology, University of Virginia, Charlottes-
ville, Virginia.
Address correspondence to Dr Kapur, Department of Neurology, Box
800394, University of Virginia-HSC, Charlottesville, VA 22908. E-mail:
jk8t@virginia.edu
Received Jun 18, 2009, and in revised form Jan 3, 2010. Accepted for
publication Jan 22, 2010.
Published in Wiley InterScience (www.interscience.wiley.com). DOI:
10.1002/ana.21989
Lawrence et al: Endogenous Neurosteroids
May, 2010 689