Robert A. Smith

Background: Migraine is a complex neurovascular disorder with a substantial genetic component, yet many contributing loci remain poorly characterised. Methods: This study investigated the association between 21 biologically prioritised single nucleotide variants (SNVs) and migraine susceptibility in a case-control cohort of 548 individuals of European ancestry, of whom 304 (164 cases, 140 controls) remained after quality control and principal component analysis (PCA). Genotyping was performed using a targeted Sequenom MassARRAY platform, and substantial missingness (mean 30.3% per SNV) was addressed using multiple imputation by chained equations (MICE). Association testing was conducted using three complementary logistic regression frameworks: unadjusted single-variant analysis, covariate-adjusted marginal models, and a multivariable joint model incorporating all SNVs with L2 regularisation. Results: Across analyses, two variants in ASTN2 (rs1052053 and rs6478241) showed the most robust associations with migraine, surviving Bonferroni correction in the joint model (p = 0.001 and p = 0.002, respectively) and false discovery rate (FDR) correction in marginal models (q = 0.003 for both). A third variant, rs7304841 (12p12), demonstrated a risk-increasing effect that reached FDR significance in marginal analysis (q = 0.035) and remained nominally significant in the joint model. In contrast, rs62624978 in CTC1 showed a strong signal in unadjusted analysis (OR = 0.217, p = 0.0014) and remained nominally significant after adjustment (p = 0.011), although it did not survive multiple-testing correction in imputed models. The joint model demonstrated good discriminatory performance (AUC = 0.822), though this is not intended as a predictive tool. Biologically, implicated loci suggest contributions from both neuronal circuit organisation (ASTN2) and telomere and vascular maintenance pathways (CTC1), supporting a broader neurovascular model of migraine susceptibility. Conclusions: These findings are consistent with shared genetic architecture between migraine and microvascular dysfunction, potentially involving endothelial integrity, neurovascular coupling, and cortical excitability mechanisms.

Background: Familial hemiplegic migraine (FHM) is a rare and severe form of migraine disorder featuring aura symptoms that include hemiplegia during attacks. While pathogenic missense variants in CACNA1A, ATP1A2, and SCN1A can cause FHM or its sporadic form, they explain less than 20% of suspected hemiplegic migraine cases, suggesting the involvement of other genes or genetic variations, potentially including copy number variations (CNVs). PPRT2 gene variants including CNVs have also been implicated in hemiplegic migraine. Methods: Multiplex ligation-dependent probe amplification (MLPA) assays were used to investigate the presence of CNVs in the CACNA1A, SCN1A, ATP1A2, and PRRT2 genes in a cohort of 170 unrelated probands suspected to have FHM who had tested negative for pathogenic missense or small indel variants within these genes. Potential CNVs were subsequently confirmed using quantitative PCR. Results: In 15 patients referred for FHM genetic testing, various CNVs in the target genes were detected by MLPA and subsequently validated by quantitative PCR. CACNA1A exon duplications were identified in six patients and deletions found in two. Two patients had ATP1A2 exon deletions, while one had a duplication. For SCN1A, exon deletions were found in three patients and a duplication in one. PRRT2 exon deletions were detected in five patients, with a single nucleotide polymorphism (SNP) array confirming a deletion spanning PRRT2 and neighbouring loci including 26 genes in one of those. Three patients had CNVs in more than one FHM gene. Conclusions: Our study demonstrates the presence of CNVs in FHM genes in a subset of hemiplegic migraine cases (~9%), suggesting a likely role in the disorder and highlighting the need to explore structural variation in addition to the commonly interrogated genetic mutation points. These findings contribute to further understanding of genetic mechanisms that underlie hemiplegic migraine and may inform improved diagnostic and therapeutic strategies.

Background Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an autosomal dominant neurological disorder caused by mutations in the NOTCH3 gene. Disease-causing variants in NOTCH3 are primarily missense variants altering the number of cysteine residues in the translated NOTCH3 protein. The genetic screening of the NOTCH3 gene is currently considered the gold standard for CADASIL diagnosis. Methods The Genomics Research Centre has been performing diagnostic genetic testing for CADASIL since 1997. A total of 1281 patient samples suspected of having CADASIL were screened for NOTCH3 mutations from January 1, 1997, to October 1, 2025. Genomic sequencing was performed using Sanger sequencing of selected NOTCH3 exons or using next-generation sequencing to screen the entire NOTCH3 gene. Results In total, 12.1% of patients had a cysteine-altering NOTCH3 variant, including 49 variants in exons 2-24, and two variants in non-EGFr encoding exons. We also report the first CADASIL patient who is a compound heterozygote for two known pathogenic cysteine-altering NOTCH3 variants, who presented with a severe early onset of stroke, migraine, and white matter changes. Conclusions The compound heterozygosity identified in this patient appears to be associated with an early onset of CADASIL symptoms. Our study contributes to the elucidation of the spectrum of NOTCH3 variants associated with CADASIL. The majority of patients tested for CADASIL in this study did not contain a variant in NOTCH3, indicating that there are other genes or genetic variants contributing to disease in these patients.

Background: Hemiplegic migraine (HM) is a rare and severe subtype of migraine with a complex genetic basis. Although pathogenic variants in CACNA1A, ATP1A2, and SCN1A explain some familial cases, a significant proportion of patients remain genetically undiagnosed. Increasing evidence points to an overlap between migraine and cerebral small vessel disease (SVD), implicating vascular dysfunction in HM pathophysiology. Objective: This study aimed to identify rare or novel variants in genes associated with SVD in a cohort of patients clinically diagnosed with HM who tested negative for known familial hemiplegic migraine (FHM) pathogenic variants. Methods: We conducted a case-control association analysis of whole exome sequencing (WES) data from 184 unrelated HM patients. A targeted panel of 34 SVD-related genes was assessed. Variants were prioritised based on rarity (MAF ≤ 0.05), location (exonic/splice site), and predicted pathogenicity using in silico tools. Statistical comparisons to gnomAD’s Non-Finnish European population were made using chi-square tests. Results: Significant variants were identified in several SVD-related genes, including LRP1 (p.Thr4077Arg), COL4A1 (p.Pro54Leu), COL4A2 (p.Glu1123Gly), and TGFBR2 (p.Met148Leu and p.Ala51Pro). The LRP1 variant showed the strongest association (p < 0.001). All key variants demonstrated pathogenicity predictions in multiple computational models, implicating them in vascular dysfunction relevant to migraine mechanisms. Conclusions: This study provides new insights into the genetic architecture of hemiplegic migraine, identifying rare and potentially deleterious variants in SVD-related genes. These findings support the hypothesis that vascular and cellular maintenance pathways contribute to migraine susceptibility and may offer new targets for diagnosis and therapy.

There is evidence to suggest that hormonal migraine is associated with altered cerebrovascular function. We aimed to investigate whether the expression of genes related to endothelial function in venous blood (1) might influence cerebrovascular function, (2) differs between hormonal migraineur and non-migraineur women, and (3) changes following resveratrol supplementation. This study utilised data obtained from 87 women (59 hormonal migraineurs and 28 controls) where RNA from venous blood was used to quantify gene expression and transcranial Doppler ultrasound was used to evaluate cerebrovascular function. Spearman’s correlation analyses were performed between gene expression, cerebrovascular function, and migraine-related disability. We compared the expression of genes associated with endothelial function between migraineurs and non-migraineurs, and between resveratrol and placebo. The expression of several genes related to endothelial function was associated with alterations in cerebrovascular function. Notably, the expression of CALCA was associated with increased neurovascular coupling capacity (p = 0.013), and both CALCA (p = 0.035) and VEGF (p = 0.014) expression were associated with increased cerebral blood flow velocity in the overall study population. Additionally, VCAM1 expression correlated with decreased pulsatility index (a measure of cerebral arterial stiffness) (p = 0.009) and headache impact test-6 scores (p = 0.007) in the migraineurs. No significant differences in gene expression were observed between migraineurs and controls, or between placebo and resveratrol treatments in migraineurs. Thus, altering the expression of genes related to endothelial function may improve cerebrovascular function and decrease migraine-related disability.

The BRAF V600E mutation in papillary thyroid carcinoma is the major mutation in classical subtype of papillary thyroid carcinoma and other cancers. It is the most studied predictor of clinical and pathological characteristics as well as molecular targets for cancer therapy. On the other hand, there is potential for many more forms of activating mutation in BRAF that are not detectable by simple assays to detect V600E, or even simple polymerase chain reaction (PCR)-based sequencing for full-length BRAF. Such activating mutations could arise from larger-scale rearrangements which may apparently leave no sequence change to BRAF while causing increased expression or activation by unusual means, such as gene fusion. Detection of these kinds of changes can take place using a variety of methods, though capture-based sequencing can identify the existence of such forms of mutant BRAF without needing foreknowledge of the loci involved in these kinds of mutation. In this chapter, we detail a method for capture of specific DNA sequences and their amplification to prepare for massively parallel sequencing. Key words BRAF Probe capture Degenerate oligonucleotide PCR DOP PCR Papillary thyroid carcinoma

Single nucleotide polymorphisms (SNPs) can have a variety of implications for the progression and development of papillary thyroid carcinomas (PTCs). Identification of SNPs, either as germline variants or mutations occurring in tumor tissue, can thus have useful implications for patient management. There are many potential methods that can be used to identify a specific SNP or other genetic variant, and among these is high-resolution melting (HRM). HRM can be used to detect the presence of a genetic variant in a single sealed tube, involving undertaking a polymerase chain reaction (PCR) in the presence of a saturating intercalating dye. Once PCR is complete, the amplicons produced can be melted through incremental raising of the temperature and the genotype of individual samples determined by changes in the change in fluorescence as the fluorescent dye is released by the melting DNA. In this chapter, we detail a method for the genotyping of DNA samples using HRM. Key words High-resolution melting HRM Polymerase chain reaction PCR Single nucleotide polymorphisms SNP Cancer management Mutations

Hemiplegic migraine (HM) is a rare migraine disorder with aura subtype including temporary weakness and visual, sensory, and/or speech symptoms. To date, three main genes—CACNA1A, ATP1A2, and SCN1A—have been found to cause HM. These encode ion channels or transporters, important for regulating neuronal ion balance and synaptic transmission, leading to HM being described as a channelopathy. However, CACNA1A, ATP1A2, and SCN1A mutations, and applied targeted analysis of whole exome sequencing data for rare missense or potential protein-altering variants in the PRRT2, PNKD, SLC1A3, SLC2A1, SLC4A4, ATP1A3, and ATP1A4 genes. We identified known mutations and some potentially pathogenic variants in each of these genes in specific cases, suggesting that their screening improves molecular diagnosis for the disorder. However, the majority of HM patients were found not to have candidate mutations in any of the previously reported HM genes, suggesting that additional genetic factors contributing to the disorder are yet to be identified.

Episodic Ataxias (EAs) are a small group (EA1–EA8) of complex neurological conditions that manifest as incidents of poor balance and coordination. Diagnostic testing cannot always find causative variants for the phenotype, however, and this along with the recently proposed EA type 9 (EA9), suggest that more EA genes are yet to be discovered. We previously identified disease-causing mutations in the CACNA1A gene in 48% (n = 15) of 31 patients with a suspected clinical diagnosis of EA2, and referred to our laboratory for CACNA1A gene testing, leaving 52% of these cases (n = 16) with no molecular diagnosis. In this study, whole exome sequencing (WES) was performed on 16 patients who tested negative for CACNA1A mutations. Tiered analysis of WES data was performed to first explore (Tier-1) the ataxia and ataxia-associated genes (n = 170) available in the literature and databases for comprehensive EA molecular genetic testing; we then investigated 353 ion channel genes (Tier-2). Known and potential causal variants were identified in n = 8/16 (50%) patients in 8 genes (SCN2A, p.Val1325Phe; ATP1A3, p.Arg756His; PEX7, p.Tyr40Ter; and KCNA1, p.Arg167Met; CLCN1, p.Gly945ArgfsX39; CACNA1E, p.Ile614Val; SCN1B, p.Cys121Trp; and SCN9A, p.Tyr1217Ter). These results suggest that mutations in these genes might cause an ataxia phenotype or that combinations of more than one mutation contribute to ataxia disorders.

Early detection of cancer and the monitoring of cancer recurrence in treated patients are significant challenges in esophageal squamous cell carcinoma (ESCC). Liquid biopsy is the identification of tumor biomarkers from minimally invasive samples of biological fluids, including urine, blood, stool, saliva, or cerebrospinal fluid. Liquid biopsy offers a potential solution to the problems of detection and surveillance as DNA shed from cancer cells as cell-free DNA or in exosomes can be detected in body fluids. By detecting these DNAs, we can identify the presence of cancer-associated mutations for basic detection, as well as to obtain information on the recurrence and evolution of disease following initial treatment. These sources of information have the potential to significantly improve the management of patients with ESCC. In this chapter, we detail a method for the isolation of cell-free DNA from blood plasma and DNA associated with exosomes in blood from patients with esophageal squamous cell carcinomas.