Familial hemiplegic migraine in pediatric patients: A genetic, clinical, and follow-up study

OBJECTIVE

The aim of this study was to describe a cohort of pediatric patients with genetically confirmed familial hemiplegic migraine (FHM). The knowledge of genotype-phenotype correlations may suggest prognostic factors associated with severe phenotypes.

BACKGROUND

Hemiplegic migraine is a rare disease and data concerning the pediatric population are even more rare as they are often extrapolated from mixed cohorts.

METHODS

We selected patients who met International Classification of Headache Disorders, third edition criteria for FHM, who had a molecular diagnosis, and whose first attack occurred under the age of 18 years.

RESULTS

We enrolled nine patients (seven males and two females) first referred to our three centers. Three of the nine (33%) patients had calcium voltage-gated channel subunit alpha1 A (CACNA1A) mutations, five (55%) had ATPase Na+/K+ transporting subunit alpha 2 (ATP1A2) mutations, and one had both genetic mutations. The patients experienced at least one aura feature other than hemiplegia during the first attack. The mean (SD) duration of HM attacks in the sample was 11.3 (17.1) h; 3.8 (6.1) h in the ATP1A2 group, and 24.3 (23.5) h in the CACNA1A group. The mean (SD, range) duration of follow-up was 7.4 (2.2, 3-10) years. During the first year from the disorder's onset, only four patients had additional attacks. Over the course of follow-up, the attack frequency overall was 0.4 attacks/year without a difference between the two groups (CACNA1A and ATP1A2).

CONCLUSION

The study data show that most of our patients with early-onset FHM experienced infrequent and non-severe attacks, which improved over time. Furthermore, the clinical course revealed neither the appearance of novel neurological disorders or a deterioration of basic neurological or cognitive functioning.

CACNA1A-Related Channelopathies: Clinical Manifestations and Treatment Options

In the last decade, variants in the Ca2+ channel gene CACNA1A emerged as a frequent aetiology of rare neurological phenotypes sharing a common denominator of variable paroxysmal manifestations and chronic cerebellar dysfunction. The spectrum of paroxysmal manifestations encompasses migraine with hemiplegic aura, episodic ataxia, epilepsy and paroxysmal non-epileptic movement disorders. Additional chronic neurological symptoms range from severe developmental phenotypes in early-onset cases to neurobehavioural disorders and chronic cerebellar ataxia in older children and adults.In the present review we systematically approach the clinical manifestations of CACNA1A variants, delineate genotype-phenotype correlations and elaborate on the emerging concept of an age-dependent phenotypic spectrum in CACNA1A disease. We furthermore reflect on different therapy options available for paroxysmal symptoms in CACNA1A and address open issues to prioritize in the future clinical research.

Ten years of follow-up in a large family with familial hemiplegic migraine type 1: Clinical course and implications for treatment

Background Familial hemiplegic migraine (FHM) is a rare, genetic form of migraine with aura. The severity of the aura imposes an effective prophylaxis that is currently based on standard anti-migraine drugs. To this concern, only short-term reports are currently available. Methods Eight patients from a multigenerational FHM type 1 family harbouring a T666M mutation in the CACNA1A gene were referred to our ataxia outpatient clinic. Medical history, general and neurological examination as well as therapeutic approaches were recorded regularly on a routine basis for an average period of 13 years (range 9-15 years). Brain imaging studies and EEG data were also collected. Results Our long-term follow-up revealed that ictal manifestations, which usually improve after the adolescence, may reoccur later in the adulthood. Permanent neurological signs as assessed by means of clinical evaluation as well as follow-up MRIs, EEGs and neuropsychological testing remained stable. Interval therapy with non-selective calcium antagonists reduced the burden of migraine attacks and was well tolerated in the long term.

Migraine variants--occurrence in pediatric neurology practice

Migraine is common in pediatric neurology practice, while migraine variants are rare and pose diagnostic problems.

OBJECTIVE

The aim was to establish the occurrence of migraine variants in pediatric neurology practice and among migraine, and to discuss their presentation.

PATIENTS AND METHODS

The files of 2509 newly diagnosed patients, aged 0-18 years, treated as in- and out-patients in the Neuropediatric Ward at the Plovdiv Medical University Hospital between 2002 and 2006 were examined retrospectively. Migraine forms were diagnosed according to ICHD-II. Benign paroxysmal torticolis and alternating hemiplegia of childhood were also accepted as migraine variants according to proposed diagnostic criteria in the appendix of ICHD-II. Some specific forms like acute confusional migraine (ACM), Alice in wonderland syndrome (AWS), ophthalmoplegic migraine were also diagnosed although not included as migraine variants in the ICHD-II classification.

RESULTS

111 patients met diagnostic criteria for migraine. Patients with migraine variants comprised 24.3% of migrainous cases. Basilar type migraine was the most common (6.3% of all migrainous patients), followed by benign paroxysmal vertigo (5.4%), hemiplegic migraine (3.6%), ACM (2.7%), benign paroxysmal torticolis (2.7%), typical aura without headache (1.8%), abdominal migraine (1.8%), AWS (0.9%), ophthalmoplegic migraine (0.9%) and cyclical vomiting (0.9%). Alternating hemiplegia of childhood and retinal migraine was not found. Some patients either presented or were classified as different migraine variants.

CONCLUSION

Basilar type migraine was the most common migraine variant. ACM and AWS should be regarded as distinct entities in the ICHD as migraine with complex aura. Benign paroxysmal torticollis also deserves its place as a migraine variant. Cases of ophthalmoplegic migraine with spontaneous remission and no cranial nerve enhancement on MRI should be considered as migraine form. Analyzing migraine variants will contribute to better awareness and adequate diagnosis.

Pearls and pitfalls in genetic studies of migraine

Purpose of review

Migraine is a prevalent neurovascular brain disorder with a strong genetic component, and different methodological approaches have been implemented to identify the genes involved. This review focuses on pearls and pitfalls of these approaches and genetic findings in migraine.

Summary

Common forms of migraine (i.e. migraine with and without aura) are thought to have a polygenic make-up, whereas rare familial hemiplegic migraine (FHM) presents with a monogenic pattern of inheritance. Until a few years ago only studies in FHM yielded causal genes, which were identified by a classical linkage analysis approach. Functional analyses of FHM gene mutations in cellular and transgenic animal models suggest abnormal glutamatergic neurotransmission as a possible key disease mechanism. Recently, a number of genes were discovered for the common forms of migraine using a genome-wide association (GWA) approach, which sheds first light on the pathophysiological mechanisms involved.

Conclusions

Novel technological strategies such as next-generation sequencing, which can be implemented in future genetic migraine research, may aid the identification of novel FHM genes and promote the search for the missing heritability of common migraine.

Genetics of migraine: an update

An important genetic component of migraine was systematically established by epidemiological studies in the 1990s. Over the past 15 years, significant progress has been made in unraveling the genetic basis and pathophysiological mechanisms of familial hemiplegic migraine, a rare and severe autosomal-dominant subtype of migraine with aura. Three different causative genes (CACNA1A, ATP1A2 and SCN1A), all of which are involved in cerebral ion translocation, have been identified. Functional studies and mouse models have shown that mutations in these genes, by different mechanisms, cause a disturbed cerebral glutamate homeostasis and, thus, increase susceptibility to cortical spreading depression, the likely correlate of migraine aura. More recently, genome-wide association studies have, for the first time, detected robust risk variants associated with the more common, genetically complex types of migraine, which has generated new perspectives for genetic research in migraine. This review summarizes the current knowledge about migraine genetics, with a focus on both familial hemiplegic migraine and recent results of genome-wide association studies.

Migraine- and dystonia-related disease-mutations of Na+/K+-ATPases: relevance of behavioral studies in mice to disease symptoms and neurological manifestations in humans

The two autosomal dominantly inherited neurological diseases: familial hemiplegic migraine type 2 (FHM2) and familial rapid-onset of dystonia-parkinsonism (Familial RDP) are caused by in vivo mutations of specific alpha subunits of the sodium-potassium pump (Na(+)/K(+)-ATPase). Intriguingly, patients with classical FHM2 and RDP symptoms additionally suffer from other manifestations, such as epilepsy/seizures and developmental disabilities. Recent studies of FHM2 and RDP mouse models provide valuable tools for dissecting the vital roles of the Na(+)/K(+)-ATPases, and we discuss their relevance to the complex patient symptoms and manifestations. Thus, it is interesting that mouse models targeting a specific α-isoform cause different, although still comparable, phenotypes consistent with classical symptoms and other manifestations observed in FHM2 and RDP patients. This review highlights that use of mouse models have broad potentials for future research concerning migraine and dystonia-related diseases, which will contribute towards understanding the, yet unknown, pathophysiologies.