Fatal familial insomnia is a prion disease with a mutation in codon 178 of the PrP gene, but the disease phenotype seems to differ from that of previously described kindreds with the same point mutation.

To assess the role of dopamine metabolism-related genes in the genetic liability to chronic headache with drug abuse (DA). We performed a genetic association study using four functional polymorphisms of the dopamine receptor 4 (DRD4), dopamine transporter (DAT), mono-amino-oxidase A (MAOA) and cathecol-O-methyl-transferase (COMT) genes in 103 patients with chronic daily headache associated with DA (CDHDA). Control samples were 117 individuals without headache or DA (controls) and 101 patients with episodic migraine without aura and without DA (MO). No differences were found at the COMT and MAOA genes among the three groups investigated. Allele 4 of DRD4 was significantly overrepresented in patients with MO compared with both controls and CDHDA. Allele 10 of the DAT gene was significantly underrepresented in patients with CDHDA when compared with the MO group. Genetic variability at the DRD4 gene is involved in the predisposition to episodic MO but not to DA, while liability to CDHDA may involve genetic variability at the DAT gene in comparison with episodic MO.

To investigate energy metabolism in migraine, we determined platelet mitochondrial enzyme activities in 40 patients with migraine with aura and in 40 patients with migraine without aura during attack-free intervals and in 24 healthy control subjects. NADH-dehydrogenase, citrate synthase and cytochrome-c-oxidase activities in both patient groups were significantly lower than in controls (p < 0.01), while NADH-cytochrome-c-reductase activity was reduced only in migraine with aura (p < 0.01). No alteration in succinate-dehydrogenase was observed. Monoamine-oxidase activity differed between sexes (p < 0.05) but within each sex group no difference was observed between patients and controls. We hypothesize that the defect in mitochondrial enzymes observed indicates a systemic impairment of mitochondrial function in migraine patients.

We assessed the role of some dopamine metabolism genes in the genetic susceptibility to migraine. We performed an association study using three functional polymorphisms: a 48-base-pair (bp) tandem repeat in the D4 dopamine receptor gene ( DRD4), a 40-bp tandem repeat in the dopamine transporter gene ( DAT) and a dinucleotide repeat in the dopamine beta-hydroxylase ( DBH) gene. Allelic and genotypic frequencies for each polymorphism were assayed in two migraine populations (93 individuals with migraine with aura (MA) and 101 with migraine without aura (MO)) and were compared with those in a control group (117 individuals). No significant differences were found between control and migraine groups for DAT and DBH polymorphisms. Instead, the distribution of alleles for the DRD4 gene in the MO group was significantly different from those in both MA and control groups, with the shortest and longest alleles being less frequent in MO. Our data indicate that MO, but not MA, shows significant genetic association with DRD4.

We collected two clinically matched samples of patients, one sample affected by migraine with aura the other by migraine without aura, to investigate the genetic determination of these conditions. A maternal and X‐linked transmission for both these diseases was considered unlikely after pedigree analysis. Classical segregation analysis indicated a likely autosomal recessive kind of transmission for both. Reduced penetrance and the h2 values, however, imply the presence of additional genetic andor environmental factors controlling the phenotypic expression of migraine.

We conducted a pedigree analysis in 222 patients with cluster headaches (CHs) in order to assess a familial predisposition to the disease. Heritability was determined by Falconer's index (from the incidence of CH among first degree relatives of probands compared with a control population), which varies between 0 and 1 (none or full genetic causation). A positive family history (I/II degree relatives) was found in 2.3% of our CH patients. Three generations were affected in one family and two generations in another two families. The calculated Falconer's heritability index was, however, only 0.26 ± 0.25 SD. Our study confirms a higher familial occurrence of CH, some families showing a pattern compatible with autosomal dominant inheritance with reduced penetrance. The low Falconer's index indicates, however, a large non‐genetic causation in most cases of CH.

We explored the potential effect of catechol-O-methyltransferase (COMT) genetic polymorphism on the pharmacokinetics and pharmacodynamics of a standard oral dose of levodopa in patients with Parkinson's disease (PD). We prospectively collected blood samples for COMT genotyping from a population of 104 PD patients. Each patient was examined by a standard oral levodopa/benserazide test, based on simultaneous serial measurements of plasma levodopa concentrations, finger-tapping motor effects and dyskinesia ratings, up to 4 hours after dosing. The main levodopa pharmacokinetic outcome variables were time to peak and peak plasma concentration, plasma elimination half-life, and the area under the plasma concentration-time curve. The main outcome levodopa pharmacodynamic variables were latency, duration, and magnitude of the motor effect elicited by the levodopa test dose, the area under the tapping effect-time curve, and the presence of dyskinesias. Nineteen patients (18%) harbored the low-activity homozygous COMT genotype (A/A), 63 patients (61%) carried the intermediate-activity heterozygous COMT genotype (A/G) and 22 patients (21%) had the high-activity homozygous COMT genotype (G/G). The three groups were comparable for vital and clinical characteristics. No significant difference was found in levodopa main pharmacokinetic-pharmacodynamic variables and dyskinesia incidence among the three subgroups of patients. We failed to identify clinically relevant levodopa pharmacokinetic-pharmacodynamic response patterns associated with the COMT polymorphism in PD patients.

We describe an Italian family with familial hemiplegic migraine (FHM), subtle cerebellar signs and probable linkage to chromosome 1. FHM is genetically heterogeneous; in about 50% of families it is caused by mutations within the CACNA1A gene on chromosome 19. Linkage to 1q31 and 1g21-23 has also been established. Other families do not link either to chromosome 19 or 1. Chromosome 19-linked FHM may display nystagmus and cerebellar ataxia. Affected family members were neurologically examined; linkage analysis was performed with markers for chromosomes 19p13, 1q21-23, and 1q32. Five family members had hemiplegic migraine, and 3 displayed additional cerebellar signs (scanning speech and nystagmus). In 1 patient, episodes of hemiplegic migraine triggered by mild head trauma. Epilepsy and mental retardation were also found in 1 affected relative each. Lod scores for linkage to 19p13 were negative, while the maximum two-point lod score was 1.81 to 1q21-23. This family with FHM and associated subtle cerebellar signs, epilepsy and mental retardation showed probable linkage to 1q21-23.