Genetic Factors of Cerebral Small Vessel Disease and Their Potential Clinical Outcome

Association of the COL4A2 Gene Polymorphisms with Primary Intracerebral Hemorrhage Risk and Outcome in Chinese Han Population

The relationship of single nucleotide polymorphisms (SNPs) in COL4A2 gene with risk and outcome of primary intracerebral hemorrhage (ICH) in the Chinese Han population remains unclear, which was investigated in this study. Primary ICH patients and non-stroke controls of Chinese Han ethnicity were enrolled. The genotypes of 8 tag-SNPs were determined using a custom-by-design 48-Plex SNPscan Kit. Poor 3-month outcome was defined as modified Rankin Scale score 4-6. Logistic regression was employed to examine association between COL4A2 variants and risk and poor outcome of primary ICH. 323 patients with primary ICH and 376 stroke-free controls were included. Compared to controls, the rs1049931 G and rs1049906 C alleles were associated with increased ICH risk (p = 0.027 and 0.033), and these two allele counts increased this risk after adjustments respectively (additive model: adjusted OR [aOR] 1.41, 95% CI 1.03-1.94, corrected p = 0.043; aOR 1.37, 95% CI 1.01-1.86, corrected p = 0.043). The rs1049931 AG/GG and rs1049906 CT/CC genotypes showed increased susceptibility to non-lobar hemorrhage (aOR 1.63, 95% CI 1.06-2.50, p = 0.025; aOR 1.63, 95% CI 1.07-2.47, p = 0.022). Haplotype analysis revealed an association between rs1049906-rs1049931 haplotype CG and ICH risk (OR 1.36, 95% CI 1.05-1.78, p = 0.021). Regarding clinical outcome, the rs3803230 C allele (dominant model: aOR 1.94, 95% CI 1.04-3.63, p = 0.037) and haplotype AC of rs7990214-rs3803230 (OR 1.98, 95% CI 1.13-3.46, p = 0.015) contributed to 3-month poor outcome. The COL4A2 polymorphisms are associated with an increased risk of primary ICH, mainly non-lobar hemorrhage, and with long-term poor outcome after ICH in Chinese Han population.

Where is VALDO? VAscular Lesions Detection and segmentatiOn challenge at MICCAI 2021

Imaging markers of cerebral small vessel disease provide valuable information on brain health, but their manual assessment is time-consuming and hampered by substantial intra- and interrater variability. Automated rating may benefit biomedical research, as well as clinical assessment, but diagnostic reliability of existing algorithms is unknown. Here, we present the results of the VAscular Lesions DetectiOn and Segmentation (Where is VALDO?) challenge that was run as a satellite event at the international conference on Medical Image Computing and Computer Aided Intervention (MICCAI) 2021. This challenge aimed to promote the development of methods for automated detection and segmentation of small and sparse imaging markers of cerebral small vessel disease, namely enlarged perivascular spaces (EPVS) (Task 1), cerebral microbleeds (Task 2) and lacunes of presumed vascular origin (Task 3) while leveraging weak and noisy labels. Overall, 12 teams participated in the challenge proposing solutions for one or more tasks (4 for Task 1-EPVS, 9 for Task 2-Microbleeds and 6 for Task 3-Lacunes). Multi-cohort data was used in both training and evaluation. Results showed a large variability in performance both across teams and across tasks, with promising results notably for Task 1-EPVS and Task 2-Microbleeds and not practically useful results yet for Task 3-Lacunes. It also highlighted the performance inconsistency across cases that may deter use at an individual level, while still proving useful at a population level.

Functional genomics in stroke: current and future applications of iPSCs and gene editing to dissect the function of risk variants

Stroke is an important disease with unmet clinical need. To uncover novel paths for treatment, it is of critical importance to develop relevant laboratory models that may help to shed light on the pathophysiological mechanisms of stroke. Induced pluripotent stem cells (iPSCs) technology has enormous potential to advance our knowledge into stroke by creating novel human models for research and therapeutic testing. iPSCs models generated from patients with specific stroke types and specific genetic predisposition in combination with other state of art technologies including genome editing, multi-omics, 3D system, libraries screening, offer the opportunity to investigate disease-related pathways and identify potential novel therapeutic targets that can then be tested in these models. Thus, iPSCs offer an unprecedented opportunity to make rapid progress in the field of stroke and vascular dementia research leading to clinical translation. This review paper summarizes some of the key areas in which patient-derived iPSCs technology has been applied to disease modelling and discusses the ongoing challenges and the future directions for the application of this technology in the field of stroke research.

Small-vessel disease in the brain

Cerebral small-vessels are generally located in the brain at branch points from major cerebral blood vessels and perfuse subcortical structures such as the white matter tracts, basal ganglia, thalamus, and pons. Cerebral small-vessel disease (CSVD) can lead to several different clinical manifestations including ischemic lacunar stroke, intracerebral hemorrhage, and vascular dementia. Risk factors for CSVD overlap with conventional vascular risk factors including hypertension, diabetes mellitus, and hypercholesterolemia, as well as genetic causes. As in cardiovascular disease, treatment of CSVD involves both primary and secondary prevention. Aspirin has not been established as a primary prevention strategy for CSVD among the general population; however, long-term antiplatelet therapy with aspirin alone continues to be the mainstay of secondary stroke prevention for non-cardioembolic ischemic stroke and high-risk TIA.

Plasma inflammatory biomarkers in cerebral small vessel disease: A review

Cerebral small vessel disease (CSVD) is a group of pathological processes affecting small arteries, arterioles, capillaries, and small veins of the brain. It is one of the most common subtypes of cerebrovascular diseases, especially highly prevalent in elderly populations, and is associated with stroke occurrence and recurrence, cognitive impairment, gait disorders, psychological disturbance, and dysuria. Its diagnosis mainly depends on MRI, characterized by recent small subcortical infarcts, lacunes, white matter hyperintensities (WMHs), enlarged perivascular spaces (EPVS), cerebral microbleeds (CMBs), and brain atrophy. While the pathophysiological processes of CSVD are not fully understood at present, inflammation is noticed as playing an important role. Herein, we aimed to review the relationship between plasma inflammatory biomarkers and the MRI features of CSVD, to provide background for further research.

Clinical Study on Blood Pressure Variability, Montreal Cognitive Assessment and Arteriosclerosis Index in Patients with Cerebral Small Vessel Disease Treated with Integrated Traditional Chinese and Western Medicine by Invigorating Kidney and Removing Blood Stasis

Objective

To explore the clinical improvement in blood pressure variability, Montreal Cognitive Assessment, and angiosclerosis index in patients with cerebral small vessel disease treated with integrated traditional Chinese and Western medicine.

Methods

A randomized controlled study of patients with cerebral small vessel disease who were treated in our hospital from November 1, 2018, to January 31, 2022. The enrolled patients were randomized into 2 groups according to the random numbers: an observation group treated with integrated traditional Chinese and Western medicine and a control group treated with Western medicine only. Blood pressure variability, Montreal Cognitive Assessment (MoCA), and angiosclerosis index were compared between the two groups.

Results

There were 71 qualified cases in the observation group and 58 qualified cases in the control group. Before treatment, the indicators between the two groups were comparable (P > 0.05). After treatment, the mean values of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were significantly decreased (P < 0.05); the decrease of 24hSBP-coefficient of variation (CV), daytime SBP (dSBP)-CV, 24hSBP-standard deviation (SD), and dSBP-SD in the observation group was significantly better than that in the control group; the MoCA scores of the observation group were significantly higher than those of the control group ((P < 0.05); the ABI and PWV were significantly different between the two groups (P < 0.05); TC, TG, HDL-C, and LDL-C in observation group decreased after treatment, and HDL-C increased significantly (P < 0.05).

Conclusion

Integrative traditional Chinese and Western medicine treatment can further reduce the blood pressure variability, especially systolic blood pressure; improve the MoCA score and cognitive function, increase the ankle-brachial index, reduce pulse wave velocity and the degree of arteriosclerosis; and improve lipid metabolism a comprehensive intervention role.

Systematic Review of Cerebral Phenotypes Associated With Monogenic Cerebral Small-Vessel Disease

Background Cerebral small-vessel disease (cSVD) is an important cause of stroke and vascular dementia. Most cases are multifactorial, but an emerging minority have a monogenic cause. While NOTCH3 is the best-known gene, several others have been reported. We aimed to summarize the cerebral phenotypes associated with these more recent cSVD genes. Methods and Results We performed a systematic review (PROSPERO [International Prospective Register of Systematic Reviews]: CRD42020196720), searching Medline/Embase (conception to July 2020) for any language publications describing COL4A1/2, TREX1, HTRA1, ADA2, or CTSA pathogenic variant carriers. We extracted data about individuals' characteristics and clinical and vascular radiological cerebral phenotypes. We summarized phenotype frequencies per gene, comparing patterns across genes. We screened 6485 publications including 402, and extracted data on 390 individuals with COL4A1, 123 with TREX1, 44 with HTRA1 homozygous, 41 with COL4A2, 346 with ADA2, 82 with HTRA1 heterozygous, and 14 with CTSA. Mean age ranged from 15 (ADA2) to 59 years (HTRA1 heterozygotes). Clinical phenotype frequencies varied widely: stroke, 9% (TREX1) to 52% (HTRA1 heterozygotes); cognitive features, 0% (ADA2) to 64% (HTRA1 homozygotes); and psychiatric features, 0% (COL4A2; ADA2) to 57% (CTSA). Among individuals with neuroimaging, vascular radiological phenotypes appeared common, ranging from 62% (ADA2) to 100% (HTRA1 homozygotes; CTSA). White matter lesions were the most common pathology, except in ADA2 and COL4A2 cases, where ischemic and hemorrhagic lesions dominated, respectively. Conclusions There appear to be differences in cerebral manifestations across cSVD genes. Vascular radiological changes were more common than clinical neurological phenotypes, and present in the majority of individuals with reported neuroimaging. However, these results may be affected by age and biases inherent to case reports. In the future, better characterization of associated phenotypes, as well as insights from population-based studies, should improve our understanding of monogenic cSVD to inform genetic testing, guide clinical management, and help unravel underlying disease mechanisms.

Lipid-Based Nanocarriers via Nose-to-Brain Pathway for Central Nervous System Disorders

Neurodegenerative disorders are distinguished by the gradual deterioration of the nervous system's structure and function due to oxidative stress, mitochondrial dysfunction, protein misfolding, excitotoxicity, and neuroinflammation. Among these NDs, Alzheimer's disease, Huntington's disease, Parkinson's disease, and amyotrophic lateral sclerosis characterized an increasing dysfunction and loss of neuronal structure leading to neuronal cell death. Although there is currently no drug to totally reverse the effects of NDs, such novel formulations and administration routes are developed for better management and nose-to-brain delivery is one of delivery for treating NDs. This review aimed to highlight advances in research on various lipid based nanocarriers such as liposomes, solid lipid nanoparticles, nanostructured lipid carriers, microemulsion, nanoemulsion, and cubosomes which are reported to treat and alleviate the symptoms of NDs via nose-to-brain route. The challenges during clinical translation of lipid nanocarriers from bench to bed side is also discussed.

The Genetic Basis of Strokes in Pediatric Populations and Insight into New Therapeutic Options

Strokes within pediatric populations are considered to be the 10th leading cause of death in the United States of America, with over half of such events occurring in children younger than one year of life. The multifactorial etiopathology that has an influence on stroke development and occurrence signify the importance of the timely recognition of both modifiable and non-modifiable factors for adequate diagnostic and treatment approaches. The early recognition of a stroke and stroke risk in children has the potential to advance the application of neuroprotective, thrombolytic, and antithrombotic interventions and rehabilitation strategies to the earliest possible timepoints after the onset of a stroke, improving the outcomes and quality of life for affected children and their families. The recent development of molecular genetic methods has greatly facilitated the analysis and diagnosis of single-gene disorders. In this review, the most significant single gene disorders associated with pediatric stroke are presented, along with specific therapeutic options whenever they exist. Besides monogenic disorders that may present with stroke as a first symptom, genetic polymorphisms may contribute to the risk of pediatric and perinatal stroke. The most frequently studied genetic risk factors are several common polymorphisms in genes associated with thrombophilia; these genes code for proteins that are part of the coagulation cascade, fibrolysis, homocystein metabolism, lipid metabolism, or platelets. Single polymorphism frequencies may not be sufficient to completely explain the stroke causality and an analysis of several genotype combinations is a more promising approach. The recent steps forward in our understanding of the disorders underlying strokes has given us a next generation of therapeutics and therapeutic targets by which to improve stroke survival, protect or rebuild neuronal connections in the brain, and enhance neural function. Advances in DNA sequencing and the development of new tools to correct human gene mutations have brought genetic analysis and gene therapy into the focus of investigations for new therapeutic options for stroke patients.

Prevalence of cerebral small vessel disease in a Fabry disease cohort

Objective

To characterize the prevalence of brain ischemia and cerebral small vessel disease in a cohort of patients with Fabry disease (FD) seen at an academic medical center.

Background

FD is an inherited X-linked lysosomal storage disorder with central nervous system involvement. Limited data are available in the literature on the cerebrovascular neuroimaging findings in FD, and the reported prevalence of stroke symptoms and cerebral small vessel disease has varied widely.

Design/methods

Brain MRI was performed in 21 patients with FD followed at University of California Irvine Medical Center. Stroke symptoms were assessed and quantification of cerebral microvascular disease was performed using small vessel disease (SVD) score. Lacunes and deep white matter hyperintensities were scored on a four-point scale of 0 (absent) and 1–3 to account for increasing severity; microbleeds were scored 0 (absent) or 1 (present). The total SVD score is the sum of the three components and ranges from 0 to 7.

Results

Nearly 43% (9/21) of our FD cohort (aged 32–81 years, mean = 50) had a SVD score of one or higher, all of whom were aged 50 or more years. The most common MRI-defined SVD was white matter hyperintensities (9/9, 100%), followed by microbleeds (6/9, 66%), and lacunes (3/9, 33%). The three patients with previous strokes had some of the highest SVD scores reported in the cohort (scores 3–5).

Conclusions

In this cohort, the prevalence of SVD (43%) was three times higher than prevalence of stroke symptoms. SVD score was highest in the those who had experienced a stroke. These findings emphasize the importance of routine MRI screening of patients with FD in order to identify and treat high risk patients.

The role of vascular dementia associated genes in patients with Alzheimer's disease: A large case-control study in the Chinese population

Aim

The role of vascular dementia (VaD)‐associated genes in Alzheimer's disease (AD) remains elusive despite similar clinical and pathological features. We aimed to explore the relationship between these genes and AD in the Chinese population.

Methods

Eight VaD‐associated genes were screened by a targeted sequencing panel in a sample of 3604 individuals comprising 1192 AD patients and 2412 cognitively normal controls. Variants were categorized into common variants and rare variants according to minor allele frequency (MAF). Common variant (MAF ≥ 0.01)‐based association analysis was conducted by PLINK 1.9. Rare variant (MAF < 0.01) association study and gene‐based aggregation testing of rare variants were performed by PLINK 1.9 and Sequence Kernel Association Test‐Optimal (SKAT‐O test), respectively. Age at onset (AAO) and Mini‐Mental State Examination (MMSE) association studies were performed with PLINK 1.9. Analyses were adjusted for age, gender, and APOE ε4 status.

Results

Four common COL4A1 variants, including rs874203, rs874204, rs16975492, and rs1373744, exhibited suggestive associations with AD. Five rare variants, NOTCH3 rs201436750, COL4A1 rs747972545, COL4A1 rs201481886, CST3 rs765692764, and CST3 rs140837441, showed nominal association with AD risk. Gene‐based aggregation testing revealed that HTRA1 was nominally associated with AD. In the AAO and MMSE association studies, variants in GSN, ITM2B, and COL4A1 reached suggestive significance.

Conclusion

Common variants in COL4A1 and rare variants in HTRA1, NOTCH3, COL4A1, and CST3 may be implicated in AD pathogenesis. Besides, GSN, ITM2B, and COL4A1 are probably involved in the development of AD endophenotypes.

Rare Neurovascular Diseases in Korea: Classification and Related Genetic Variants

Rare neurovascular diseases (RNVDs) have not been well-recognized in Korea. They involve the central nervous system and greatly affect the patients' lives. However, these diseases are difficult to diagnose and treat due to their rarity and incurability. We established a list of RNVDs by referring to the previous literature and databases worldwide to better understand the diseases and their current management status. We categorized 68 RNVDs based on their pathophysiology and clinical manifestations and estimated the prevalence of each disease in Korea. Recent advances in genetic, molecular, and developmental research have enabled further understanding of these RNVDs. Herein, we review each disease, while considering its classification based on updated pathologic mechanisms, and discuss the management status of RNVD in Korea.

Emerging Concepts in Vascular Dementia: A Review

OBJECTIVE

Vascular dementia (VaD) is the second most common cause of dementia and a major health concern worldwide. A comprehensive review on VaD is warranted for better understanding and guidance for the practitioner. We provide an updated overview of the epidemiology, pathophysiological mechanisms, neuroimaging patterns as well as current diagnostic and therapeutic approaches.

MATERIALS AND METHODS

A narrative review of current literature in VaD was performed based on publications from the database of PubMed, Scopus and Google Scholar up to January, 2021.

RESULTS

VaD can be the result of ischemic or hemorrhagic tissue injury in a particular region of the brain which translates into clinically significant cognitive impairment. For example, a cerebral infarct in the speech area of the dominant hemisphere would translate into clinically significant impairment as would involvement of projection pathways such as the arcuate fasciculus. Specific involvement of the angular gyrus of the dominant hemisphere, with resultant Gerstman's syndrome, could have a pronounced effect on functional ability despite being termed a "minor stroke". Small vessel cerebrovascular disease can have a cumulate effect on cognitive function over time. It is unfortunately well recognized that "good" functional recovery in acute ischemic or haemorrhagic stroke, including subarachnoid haemorrhage, does not necessarily translate into good cognitive recovery. The victim may often be left unable to have gainful employment, drive a car safely or handle their affairs independently.

CONCLUSIONS

This review should serve as a compendium of updated information on VaD and provide guidance in terms of newer diagnostic and potential therapeutic approaches.

GJA1 Gene Polymorphisms and Topographic Distribution of Cranial MRI Lesions in Cerebral Small Vessel Disease

Vascular endothelial cell (EC) and blood–brain barrier (BBB) dysfunction is the core pathogenesis of cerebral small vessel disease (CSVD). Moreover, animal experiments have shown the importance of connexin (Cx)-43 in EC and BBB function. In this study, we recruited 200 patients diagnosed with sporadic CSVD. Initially, we examined imaging scores of white matter hyperintensities (WMH), lacunar infarction (LI), and cerebral microbleeds (CMB). Additionally, we performed next-generation sequencing of the GJA1 gene (Cx43 coding gene) to examine correlation between these single-nucleotide polymorphisms and the burden and distribution of CSVD. Fourteen target loci were chosen. Of these, 13 loci (92.9%) contributed toward risk for cerebellar LI, one locus (7.1%) was shown to be a protective factor for lobar CMB after FDR adjustment. In conclusion, single-nucleotide polymorphisms in the GJA1 gene appear to affect the distribution but not severity of CSVD.

Association between Intracranial Arterial Dolichoectasia and Cerebral Small Vessel Disease and Its Underlying Mechanisms

Intracranial arterial dolichoectasia (IADE), also known as dilatative arteriopathy of the brain vessels, refers to an increase in the length and diameter of at least one intracranial artery, and accounts for approximately 12% of all patients with stroke. However, the association of IADE with stroke is usually unclear. Cerebral small vessel disease (CSVD) is characterized by pathological changes in the small vessels. Clinically, patients with CSVD can be asymptomatic or present with stroke or cognitive decline. In the past 20 years, a series of studies have strongly promoted an understanding of the association between IADE and CSVD from clinical and pathological perspectives. It has been proposed that IADE and CSVD may be attributed to abnormal vascular remodeling driven by an abnormal matrix metalloproteinase/tissue inhibitor of metalloproteinase pathway. Also, IAD-Erelated hemodynamic changes may result in initiation or progression of CSVD. Additionally, genetic factors are implicated in the pathogenesis of IADE and CSVD. Patients with Fabry’s disease and late-onset Pompe’s disease are prone to developing concomitant IADE and CSVD, and patients with collagen IV alpha 1 or 2 gene (COL4A1/COL4A2) and forkhead box C1 (FOXC1) variants present with IADE and CSVD. Race, strain, familial status, and vascular risk factors may be involved in the pathogenesis of IADE and CSVD. As well, experiments in mice have pointed to genetic strain as a predisposing factor for IADE and CSVD. However, there have been few direct genetic studies aimed towards determining the association between IADE and CSVD. In the future, more clinical and basic research studies are needed to elucidate the causal relationship between IADE and CSVD and the related molecular and genetic mechanisms.

Heavy Metal-Induced Cerebral Small Vessel Disease: Insights into Molecular Mechanisms and Possible Reversal Strategies

Heavy metals are considered a continuous threat to humanity, as they cannot be eradicated. Prolonged exposure to heavy metals/metalloids in humans has been associated with several health risks, including neurodegeneration, vascular dysfunction, metabolic disorders, cancer, etc. Small blood vessels are highly vulnerable to heavy metals as they are directly exposed to the blood circulatory system, which has comparatively higher concentration of heavy metals than other organs. Cerebral small vessel disease (CSVD) is an umbrella term used to describe various pathological processes that affect the cerebral small blood vessels and is accepted as a primary contributor in associated disorders, such as dementia, cognitive disabilities, mood disorder, and ischemic, as well as a hemorrhagic stroke. In this review, we discuss the possible implication of heavy metals/metalloid exposure in CSVD and its associated disorders based on in-vitro, preclinical, and clinical evidences. We briefly discuss the CSVD, prevalence, epidemiology, and risk factors for development such as genetic, traditional, and environmental factors. Toxic effects of specific heavy metal/metalloid intoxication (As, Cd, Pb, Hg, and Cu) in the small vessel associated endothelium and vascular dysfunction too have been reviewed. An attempt has been made to highlight the possible molecular mechanism involved in the pathophysiology, such as oxidative stress, inflammatory pathway, matrix metalloproteinases (MMPs) expression, and amyloid angiopathy in the CSVD and related disorders. Finally, we discussed the role of cellular antioxidant defense enzymes to neutralize the toxic effect, and also highlighted the potential reversal strategies to combat heavy metal-induced vascular changes. In conclusion, heavy metals in small vessels are strongly associated with the development as well as the progression of CSVD. Chelation therapy may be an effective strategy to reduce the toxic metal load and the associated complications.

Potential Antidiabetic Activity of Extracts and Isolated Compound from Adenosma bracteosum (Bonati)

Adenosma bracteosum Bonati. (A. bracteosum) has been used in traditional and modern medicine in Vietnam for curing hepatitis. In this study, ethanol and aqueous extracts of A. bracteosum were evaluated for their α-glucosidase inhibitory activities and anti-hyperglycemic effects on glucose loaded hyperglycemic and streptozotocin (STZ) induced diabetic mice. The α-glucosidase inhibition of the extracts was evaluated by colorimetric assays, and the anti-diabetic activity was tested on a STZ-induced diabetic mice model. The ethanol and aqueous extracts showed a significant α-glucosidase inhibitory activity, which was more effective than acarbose at the same concentration. In the STZ-induced diabetic mice, both extracts showed a strong anti-hyperglycemic activity, with the group receiving 50 mg/kg of ethanol extract and the group receiving 50 mg/kg of aqueous extract presenting 64.42% and 57.69% reductions, respectively, in the blood glucose levels when compared with the diabetic control group, on day 21 (p > 0.05). Isoscutellarein-8-O-β-D-glucopyranoside (IG) was identified from the ethanol extract, which showed a strong inhibitory activity against α-glucosidase, with a ten times higher potency compared with the positive control acarbose. The anti-hyperglycemic effect of IG was effectively similar to the standard drug, glibenclamide, at the same dose of 10 mg/kg (p > 0.05). These results indicated that A. bracteosum has a great antidiabetic potential.

APP, PSEN1, and PSEN2 Mutations in Asian Patients with Early-Onset Alzheimer Disease

The number of patients with Alzheimer's disease (AD) is rapidly increasing in Asia. Mutations in the amyloid protein precursor (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2) genes can cause autosomal dominant forms of early-onset AD (EOAD). Although these genes have been extensively studied, variant classification remains a challenge, highlighting the need to colligate mutations across populations. In this study, we performed a genetic screening for mutations in the APP, PSEN1, and PSEN2 genes in 200 clinically diagnosed EOAD patients across four Asian countries, including Thailand, Malaysia, the Philippines, and Korea, between 2009 and 2018. Thirty-two (16%) patients presented pathogenic APP, PSEN1, or PSEN2 variants; eight (25%), 19 (59%), and five (16%) of the 32 patients presented APP, PSEN1, and PSEN2 variants, respectively. Among the 21 novel and known non-synonymous variants, five APP variants were found in Korean patients and one APP variant was identified in a Thai patient with EOAD. Nine, two, and one PSEN1 mutation was found in a Korean patient, Malaysian siblings, and a Thai patient, respectively. Unlike PSEN1 mutations, PSEN2 mutations were rare in patients with EOAD; only three variants were found in Korean patients with EOAD. Comparison of AD-causative point mutations in Asian countries; our findings explained only a small fraction of patients, leaving approximately 84% (p = 0.01) of autosomal dominant pedigrees genetically unexplained. We suggest that the use of high-throughput sequencing technologies for EOAD patients can potentially improve our understanding of the molecular mechanisms of AD.