The long-term use of vigabatrin and lamotrigine in patients with severe childhood onset epilepsy.

Our purpose was to compare the initial efficacy and retention at 5 years of lamotrigine (LTG) and vigabatrin (VGB) in patients with severe childhood-onset epilepsies, especially with regard to loss of efficacy. Add-on therapy in 95 young patients with severe epilepsies in a neuropaediatric department was prospectively followed in open label studies for up to 5 years. VGB group: 56 patients (mean age: 11.1 years). LTG group: 39 patients (mean age: 13.6 years). Definition of initial responders: more than 50% reduction in seizure-frequency after 6 weeks of VGB treatment or after 4 months of LTG treatment. Definition of retention at 5 years: percentage of patients still taking LTG or VGB after 5 years. Definition of loss of efficacy: return to the baseline seizure frequency. The results were: VGB group: after 6 weeks 18 of 56 patients (32%) were initial responders. The retention at 5 years was five of 56 patients (8.9%). One patient (1.8%) was still seizure free. A loss of efficacy occurred in 10 of the 18 initial responders, usually within the first 9 months after the initial response. In the LTG group, after 4 months, 11 of 39 patients (28%) were initial responders. The retention at 5 years was 10 of 39 patients (25.6%). Five patients (12.8%) were still seizure free. The rate of adverse events was equal in both groups (41%). All but one occurred within the first 6 months of treatment. Our study in patients with difficult to treat childhood epilepsies suggests that in clinical practice patients were less likely to be discontinued from LTG than from VGB within 5 years, after similiar initial efficacy. This was mainly due to a loss of efficacy in VGB treatment early after initial response.

Lack of association between childhood stroke after varicella and human leukocyte antigen (HLA)-B51.

Human leukocyte antigen (HLA)-B51 has been suggested as an immunogenetic marker for a genetic predisposition to vascular occlusion in response to an immunological stimulus. Varicella has been reported to be a possible risk factor for stroke. We performed DNA-based HLA typing in 11 young patients (mean age: 5.2 years) with unexplained ischaemic stroke. In eight of them varicella had occurred before their stroke. HLA-B51 was negative in all 11 patients and we did not find any significant accumulation of other HLA-subgroups. Our study does not support an association between susceptibility to stroke after varicella and HLA-B51.

Physical mapping of the gene for juvenile nephronophthisis (NPH1) by construction of a complete YAC contig of 7 Mb on chromosome 2q13.

Familial juvenile nephronophthisis (NPH) is an autosomal recessive cystic disease of the kidney that leads to end-stage renal failure in adolescence. NPH is the most common genetic cause of end-stage renal disease in children. A gene locus for nephronophthisis (NPH1) has been mapped by linkage analysis to chromosome 2q13. We report here the construction of a complete YAC contig in the minimum genetic region for NPH1 by STS content mapping using clones of the CEPH YAC libraries. A physical map of maximum distances between 32 STS markers was constructed, thereby defining the order of a total of 27 STS markers. Since D2S340 and D2S121 have previously been identified as flanking markers to the NPH1 gene, the new contig defines on a physical map the NPH1 minimum genetic region to a 6.4-Mb interval. As a novel assignment, expressed genes, some of which may be candidates for the disease, were localized to the NPH1 region. In addition, the known interstitial telomeric repeat on chromosome 2 was physically mapped to this region. This contig assembly provides the basis for closer definition of the NPH1 critical region through identification of more narrow flanking markers and for the construction of a transcriptional map of the region towards isolation of the NPH1 gene.