A novel locus for an autosomal recessive hereditary spastic paraplegia (SPG35) maps to 16q21-q23

BACKGROUND

The hereditary spastic paraplegias (HSPs) are a group of clinically and genetically heterogeneous neurodegenerative disorders in which the cardinal pathologic feature is upper motor neuron degeneration leading to progressive spasticity and weakness of the lower limbs. To date, 14 autosomal recessive HSP loci have been mapped.

METHODS

We have identified a large consanguineous Omani family in which an autosomal recessive form of HSP is segregating. The age at onset varied from 6 to 11 years and the course of the disease is progressive with intellectual disability and is associated with seizures in two individuals. To map the chromosomal location of the causative gene we undertook 250K gene chip SNP analyses of all affected individuals assuming that a founder mutation was responsible.

RESULTS

All affected individuals shared a 20.4 Mb (3.25 cM) region of homozygosity located on chromosome 16q21-q23.1, defined by SNP markers rs149428 and rs9929635 (peak multipoint lod score of 4.86). Two candidate genes, dynein, cytoplasmic 1, light intermediate chain 2 (DYNC1LI2) and vacuolar protein sorting 4 homolog A (VPS4A), were sequenced but no disease causing mutations were identified.

CONCLUSION

We have mapped the chromosomal location of a novel gene responsible for a form of hereditary spastic paraplegia (HSP) (SPG35) and defined its clinical presentation.

Genetics and Global Health Care

<i>Objectives:</i> To examine an alternative model for funding genetic health care, on a global basis. <i>Methods:</i> Internet-based national data on gross domestic product (GDP) per capita, health care funding, and public and private elements of health care costs. <i>Results:</i> Wide variation in GDP per capita and in the proportion available for health care funding. Insufficient funds are available in developing countries. <i>Conclusions:</i> Health care provision for people with genetic disorders is unlikely to be fully funded unless a different approach to management costs is undertaken. Rare genetic disorders could be funded by an insurance model which may be more equitable and which could be developed to cover the total global health care costs of the genetic disorder.

Comparing the cost effectiveness of psychiatric treatments: bulimia nervosa

We conducted an exploratory post hoc study that compared the cost effectiveness of five treatments for bulimia nervosa: 15 weeks of cognitive behavioral therapy (CB) followed by three monthly sessions, 16 weeks (Med16) and 24 weeks (Med24) of desipramine (< or = 300 mg/day), and CB combined with desipramine for those durations (Combo16 and Combo24). We illustrate how a treatment's cost effectiveness varies according to when evaluation is done and how effectiveness and cost are defined. At 32 weeks, Med16 appears the most cost-effective treatment, and Combo16 appears the least. At 1 year, Med24 appears the most cost-effective treatment, and Combo16 appears the least. Using this post hoc analysis as an example, we discuss the pitfalls and limitations of cost-effectiveness analysis of psychiatric treatments.

Predictive testing for Huntington disease: social characteristics and knowledge of applicants, attitudes to the test procedure and decisions made after testing

An investigation has been made of the social characteristics and knowledge and experience of Huntington disease (HD) for the first 80 individuals considering presymptomatic testing (applicants) at the medical genetics centres in Edinburgh and Glasgow and of attitudes to the test procedure and decisions made after testing for those who received a result. Sixty-one percent of applicants were female and 31% were over 40 years old. Almost all had a symptomatic parent but 38% did not know HD was in their family until they were over 25 years old and 48% had never received genetic counselling. Thirty-eight percent of applicants first heard of the test at the genetic clinic, 20% from a relative and 20% from the media, but none had received information from their GP. Thirty-one applicants did not have the test because they voluntarily withdrew (17 individuals), their family structure was unsuitable or no informative result was possible (11 individuals), or they were diagnosed clinically as being affected (3 individuals). Those who voluntarily withdrew did not differ significantly from the 49 who received a result in social characteristics or knowledge and experience of HD. Twenty-two individuals were found to be at increased risk (IR) (> 50% of becoming affected) and 27 to be at decreased risk (DR) (< 50% of becoming affected). There was a median period of 9 months between entering the test procedure and receiving a result and the main criticism of the procedure was that it took too long to complete and several individuals experienced considerable anxiety while awaiting their result.(ABSTRACT TRUNCATED AT 250 WORDS)

Human pancreatic carboxypeptidase B. I. Isolation, purification, and characterization of fraction II

Human carboxypeptidase B fraction II has been purified from pancreatic juice by DEAE-'Sephadex' chromatography, isoelectric focusing, and 'Sephadex' G-100 gel filtration. The enzyme has been characterized by analytical polyacrylamide disc-gel electrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, amino acid analysis Km determination, molecular weight determination on 'Sephadex' G-100, zinc analysis, and inhibition by metal chelating agents. Human carboxypeptidase B fraction II appeared homogeneous in analytical polyacrylamide disc-gel electrophoresis, but showed two components of 23,500 and 9,200 daltons in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Zinc analysis revealed 0.96 gram atoms of zinc per mole of enzyme, and a Km of 65 +/- 3 muM was determined for hydrolysis of hippuryl-L-arginine.