Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterised by the development of hamartomas in multiple organs and tissues. TSC is caused by mutations in either the TSC1 or TSC2 gene. We searched for mutations in both genes in a cohort of 490 patients diagnosed with or suspected of having TSC using a combination of denaturing gradient gel electrophoresis, single-strand conformational polymorphism, direct sequencing, fluorescent in situ hybridisation and Southern blotting. We identified pathogenic mutations in 362 patients, a mutation detection rate of 74%. Of these 362 patients, 276 had a definite clinical diagnosis of TSC and in these patients 235 mutations were identified, a mutation detection rate of 85%. The ratio of TSC2:TSC1 mutations was 3.4:1. In our cohort, both TSC1 mutations and mutations in familial TSC2 cases were associated with phenotypes less severe than de novo TSC2 mutations. Interestingly, consistent with other studies, the phenotypes of the patients in which no mutation was identified were, overall, less severe than those of patients with either a known TSC1 or TSC2 mutation.

Hereditary spinocerebellar ataxias (SCAs) are a clinically and genetically heterogeneous group of neurodegenerative disorders for which >/=14 different genetic loci have been identified. In some SCA types, expanded tri- or pentanucleotide repeats have been identified, and the length of these expansions correlates with the age at onset and with the severity of the clinical phenotype. In several other SCA types, no genetic defect has yet been identified. We describe a large, three-generation family with early-onset tremor, dyskinesia, and slowly progressive cerebellar ataxia, not associated with any of the known SCA loci, and a mutation in the fibroblast growth factor 14 (FGF14) gene on chromosome 13q34. Our observations are in accordance with the occurrence of ataxia and paroxysmal dyskinesia in Fgf14-knockout mice. As indicated by protein modeling, the amino acid change from phenylalanine to serine at position 145 is predicted to reduce the stability of the protein. The present FGF14 mutation represents a novel gene defect involved in the neurodegeneration of cerebellum and basal ganglia.

Tricho-rhino-phalangeal syndrome (TRPS) is

The 7-10-year psychological effects of presymptomatic testing for Huntington disease are described in 142 individuals and 104 partners. Questionnaires included the Beck Hopelessness Scale (A. T. Beck, A. Weissman, D. Lester, & L. Trexler, 1974), the Impact of Event Scale (M. J. Horowitz, N. Wilner. & W. Alvarez. 1979). and the General Health Questionnaire (D. P. Goldberg. 1972). Carriers and their partners were more distressed immediately after the test result, although their outlooks improved somewhat in the 2-3-year posttest period. However, they became more pessimistic thereafter, when approaching the age of onset. Carriers, who were lost to follow-up after disclosure of test results, reported more distress pretest than did retained carriers. This demonstrates that studies that report few harmful effects may have underestimated the real impact. Moreover, follow-up studies need to investigate time effects for longer than a few years.

The effects of missense changes and small inframe deletions and insertions on protein function are not easy to predict, and the identification of such variants in individuals at risk of a genetic disease can complicate genetic counselling. One option is to perform functional tests to assess whether the variants affect protein function. We have used this strategy to characterize variants identified in the TSC1 and TSC2 genes in individuals with, or suspected of having, Tuberous Sclerosis Complex (TSC). Here we present an overview of our functional studies on 45 TSC1 and 107 TSC2 variants. Using a standardized protocol we classified 16 TSC1 variants and 70 TSC2 variants as pathogenic. In addition we identified eight putative splice site mutations (five TSC1 and three TSC2). The remaining 24 TSC1 and 34 TSC2 variants were classified as probably neutral.

Autosomal dominant cerebellar ataxias (ADCAs) are genetically classified into spinocerebellar ataxias (SCAs). We describe 14 patients of a Dutch pedigree displaying a distinct SCA-phenotype (SCA27) associated with a F145S mutation in the fibroblast growth factor 14 (FGF14) gene on chromosome 13q34. The patients showed a childhood-onset postural tremor and a slowly progressive ataxia evolving from young adulthood. Dyskinesia was often present, suggesting basal ganglia involvement, which was supported by functional imaging in 1 patient. Magnetic resonance imaging (MRI) of the brain showed only moderate cerebellar atrophy in the 2 eldest patients. Neuropsychological testing indicated low IQ and deficits in memory and executive functioning. Behavioral problems were also observed. Further investigations will have to determine the role of FGF14 in the pathogenesis of neurodegeneration and the frequency of this FGF14 mutation in SCA. (c) 2005 Movement Disorder Society.

The Kabuki (Niikawa-Kuroki) syndrome was reported in 1981 by Niikawa et al. and Kuroki et al. in a total of ten unrelated Japanese children with a characteristic array of multiple congenital anomalies and mental retardation. The syndrome is characterized by a distinct face, mild to moderate mental retardation, postnatal growth retardation, dermatoglyphic and skeletal abnormalities. In Japan, the syndrome appears to have an incidence of about 1:32,000 newborns. Outside of Japan, a growing number of patients have been recognized. Clinical data are presented on 29 Caucasian patients; the patients were diagnosed over a relatively short period of time, indicating that the incidence outside of Japan is probably not lower than in Japan. A literature review of 89 patients (60 Japanese and 29 non-Japanese) is given. In 66% of the non-Japanese patients serious neurological problems were present, most notably hypotonia and feeding problems (which were not only related to the cleft palate); this was not reported in the Japanese patients. Inheritance is not clear. Most patients are isolated, sex-ratio is equal. The syndrome can be recognized in patients with cleft (lip/)palate, with mild to moderate developmental delay and in young children with hypotonia and/or feeding problems. In counselling parents, the designation "Kabuki" syndrome seems to be more appropriate than "Kabuki make-up" syndrome.

Cerebral cavernous (or capillary-venous) malformations (CCM) have a prevalence of about 0.1-0.5% in the general population. Genes mutated in CCM encode proteins that modulate junction formation between vascular endothelial cells. Mutations lead to the development of abnormal vascular structures. In this article, we review the clinical features, molecular and genetic basis of the disease, and management.