Familial hemiplegic migraine type 2 due to a novel missense mutation in ATP1A2

Background

The mechanisms of genotype-phenotype interaction in Familiar Hemiplegic migraine type 2 (FHM2) are still far from clear. Different ATP1A2 mutations have been described, with a spectrum of phenotypes ranging from mild to severe. No genotype-phenotype correlations have been attempted.

Case presentation

We describe an Italian family with FHM and a missense ATP1A2 variant (L425H) not previously described. The clinical picture was mild in all the affected members.

Conclusions

Co-segregation of the variant with the aura phenotype was complete in this family, suggesting a 100% penetrance. In silico protein prediction softwares indicate that this variant may change the 3D structure of ATPA1A2 at the cytoplasmic loop between the two central transmembrane helices. Milder FHM phenotypes are rarely reported in literature, likely because case reports are biased towards the most severe phenotypes, with milder forms possibly misdiagnosed as sporadic migraine with aura forms (MAs), even with complex auras. Further studies taking into account intra-familiar variability and functional consequences on the channel protein may help clarify genotype-phenotype correlations.

Biotin and Acetazolamide for Treatment of an Unusual Child With Autism Plus Lack of Nail and Hair Growth

BACKGROUND

Patients with autism spectrum disorder and developmental delay or encephalopathy rarely demonstrate no or negligible hair and nail growth, suggesting a biotin-responsive clinical disorder.

METHODS

A ten-year-old girl presented with features of autism spectrum disorder, isolated headaches, and episodes of headaches and limb shaking. Her medical history revealed that her hair and nails did not grow. Administration of biotin restored her nail and hair growth and improved intellectual ability and school performance. Her episodes of headaches, single limb shaking, and loss of consciousness responded to administration of acetazolamide, and her school performance and social skills further improved.

RESULTS

A de novo c.1091 C > T, p.T364M pathogenic variant was found in the ATP1A2 gene by whole-exome sequencing, but a genetic etiology in the biotin-responsive metabolic pathways was not identified.

CONCLUSIONS

The combination of biotin and acetazolamide treatment was successful in restoring normal mental function and school performance. Poor or no clinical nail and hair growth in any child with a developmental delay-autism spectrum disorder presentation should be considered as evidence for a biotin-responsive genetic disorder even when exome testing is negative.

A novel ATP1A2 gene mutation in familial hemiplegic migraine and epilepsy

BACKGROUND

Familial hemiplegic migraine (FHM) is a rare autosomal dominant migraine subtype, characterized by fully reversible motor weakness as a specific symptom of aura. Mutations in the ion transportation coding genes CACNA1A , ATP1A2 and SCN1A are responsible for the FHM phenotype. Moreover, some mutations in ATP1A2 or SCN1A also may lead to epilepsy.

CASE

Here we report on a three-generation family with five patients having a novel ATP1A2 mutation on exon 19, causing guanine-to-adenine substitution (c.2620G>A, p.Gly874Ser) that co-segregated in the five living relatives with migraine, four of whom had hemiplegic migraine. Moreover, three patients presented with epilepsy, one of whom had generalized epilepsy with febrile seizures plus (GEFS+).

CONCLUSIONS

The present study provides further evidence on the involvement of ATP1A2 mutations in both migraine and epilepsy, underlying the relevance of genetic analysis in families with a comorbidity of both disorders.