Violent behavior associated with hypocholesterolemia due to a novel APOB gene mutation.

A 26-year-old male, the index patient, presented with persecutory delusions and suicidal behavior. He had 10 paternal male relatives in two prior generations. Five of them died by violent suicide and one, of the five, also committed a double homicide. The index patient was found to be hypocholesterolemic due to being heterozygous for a novel mutation of apolipoprotein B (apoB-29.4). His mother and paternal grandmother were normocholesterolemic, whereas a surviving paternal uncle was hypocholesterolemic and heterozygous for the apoB-29.4 mutation. This indicated that the index patient's father and paternal grandfather, both of which died by violent suicide, were obligate heterozygotes for the apoB-29.4 mutation and that the index patient inherited the mutation from his paternal grandfather. The odds ratio for the association between hypocholesterolemia and violent behavior in this family, where cholesterol status was known, was 16.9 (95% confidence interval 1.1-239.3). Therefore, our results support an inheritable relationship between violent behavior and hypocholesterolemia.

Amylin gene promoter mutations predispose to Type 2 diabetes in New Zealand Maori.

AIMS/HYPOTHESIS: Amylin gene mutations are known to predispose Chinese and Japanese subjects, but not Caucasian subjects, to Type 2 diabetes. New Zealand Maori, who have a high prevalence of Type 2 diabetes, have genetic origins in South East Asia. Amylin gene mutations could therefore predispose New Zealand Maori to Type 2 diabetes. METHODS: The amylin gene was screened for mutations in the proximal promoter region, exons 1 and 2, intron 1, and coding region of exon 3 by polymerase chain reaction amplification and direct sequencing of 131 Type 2 diabetic Maori patients and 258 non-diabetic Maori control subjects. RESULTS: We identified three new amylin gene mutations: two mutations in the promoter region (-215T>G and -132G>A) and a missense mutation in exon 3 (Q10R). The -215T>G mutation was observed in 5.4% of Type 2 Maori diabetic patients and predisposed the carrier to diabetes with a relative risk of 7.23. The -215T>G mutation was inherited with a previously described amylin promoter polymorphism (-230A>C) in 3% of the Maori with Type 2 diabetes, which suggests linkage disequilibrium exists between these two mutations. The -230A>C polymorphism on its own, however, was not associated with Type 2 diabetes in Maori subjects. The -132G>A and Q10R mutations were both observed in 0.76% of Type 2 diabetic patients and were absent in non-diabetic subjects. CONCLUSION/INTERPRETATION: The amylin gene mutations identified in this study are associated with Type 2 diabetes in 7% of Maori. Amylin is likely to be an important susceptibility gene for Type 2 diabetes in Maori people.

Proteomic analysis of the brain in Alzheimer's disease: molecular phenotype of a complex disease process.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder accounting for about 50% of all dementias, yet its pathogenic mechanisms remain poorly understood. In order to provide a more complete picture of pathogenesis in AD, we analysed six human brain regions for alterations in their proteomes. Quantitative proteome analysis was used to compare signals corresponding to individual proteins between post mortem brain tissues from persons with AD, and those from age-matched nondemented control (NC) tissues. In severely injured brain regions, 76 proteins were differentially expressed in AD hippocampus compared with NC, 62 proteins were differentially expressed in temporal cortex, and 39 proteins were differentially expressed in entorhinal cortex. Significant differences were also present in relatively spared regions. Thus, 34 proteins were differentially expressed in AD cerebellum compared with NC, 125 proteins were differentially expressed in cingulate gyrus, and 75 proteins were differentially expressed in sensorimotor cortex. The identity of 37 of these proteins was determined, and the possible relevance of changes in key pathogenic pathways analysed. These studies provide a unique snapshot illustrating the complexity of interrelated disease mechanisms at work in a complex, multifactorial disease, and show that comparative proteome analysis is a method with the power to develop important new insights into pathogenic mechanisms in the dementias.

Comparative proteome analysis of the hippocampus implicates chromosome 6q in schizophrenia.

Comparative brain proteome analysis is a new strategy to discover proteins and therefore genes whose altered expression may underlie schizophrenia. This strategy does not require an a priori theory of the pathogenesis or the mode of inheritance of schizophrenia. Using proteome analysis we previously compared the hippocampal proteome, that is, those proteins expressed by the hippocampal genome, of seven schizophrenic individuals with the hippocampal proteome of seven control individuals, matched for age and post mortem delay.1 We found 18 proteins that were significantly altered in concentration in the schizophrenic hippocampus (P < 0.05), when compared to control tissue. One of these proteins was characterised, by N-terminal sequencing, as diazepam binding inhibitor whose gene maps to 6q12-q21. Here we characterise a further three of the 18 proteins as: manganese superoxide dismutase, 6q25.3, T-complex protein 1, 6q25.3-q26 and collapsin response mediator protein 2, 8p21. That three of these four characterised proteins should map to the long arm of the same chromosome is significant (P < 0.002) and suggests the importance of chromosome 6q in schizophrenia. These results indicate that antioxidant defence is altered in the schizophrenic hippocampus and suggest that segregation distortion, of schizophrenia susceptibility genes, may be a possible causative factor in the high incidence of schizophrenia. Molecular Psychiatry (2000) 5, 85-90.

A comparative proteome analysis of hippocampal tissue from schizophrenic and Alzheimer's disease individuals.

The proteins expressed by a genome have been termed the proteome. Comparative proteome analysis of brain tissue offers a novel means to identify biologically significant gene products that underlie psychopathology. In this study we collected post mortem hippocampal tissue from the brains of seven schizophrenic, seven Alzheimer's disease (AD) and seven control individuals. Hippocampal proteomes were visualised by two-dimensional gel electrophoresis of homogenised tissue. A mean of 549 (s.d. 35) proteins were successfully matched between each disease group and the control group. In comparison with the control hippocampal proteome, eight proteins in the schizophrenic hippocampal proteome were found to be decreased and eight increased in concentration, whereas, in the AD hippocampal proteome, 35 proteins were decreased and 73 were increased in concentration (P<0.05). One protein, which was decreased in concentration in both diseases, was characterised as diazepam binding inhibitor (DBI) by N-terminal sequence analysis. DBI can regulate the action of the GABA(A) receptor. Protein changes involved 6% of the assessed AD hippocampal proteome, whereas, in schizophrenia protein changes involved less than 1% of the assessed hippocampal proteome. We conclude that schizophrenia has a subtle neuropathological presentation and comparative proteome analysis is a viable means by which to investigate diseases of the brain at the molecular level.

Proteome map of the human hippocampus.

The proteins expressed by a genome have been termed the proteome. By comparing the proteome of a disease-affected tissue with the proteome of an unaffected tissue it is possible to identify proteins that play a role in a disease process. The hippocampus is involved in the processing of short-term memory and is affected in Alzheimer's disease. Any comparative proteome analysis that can identify proteins important in a disease affecting the hippocampus requires the characterization of the normal hippocampal proteome. Therefore, we homogenised normal hippocampal tissue and separated the proteins by two-dimensional polyacrylamide gel electrophoresis (2DE). Seventy-two unique protein spots were collected from Coomassie blue-stained 2DE gels and subjected to in-gel digestion with trypsin, reversed-phase high-pressure liquid chromatography peptide separation, and N-terminal protein sequencing. Sufficient protein sequence was obtained to successfully characterize 66 of the 72 protein spots chosen (92%). Three of the 66 proteins were not present in any database (4.5%). The characterized proteins comprised two dominant functional groups, i.e., enzymes involved in intermediary cellular metabolism (40%), and proteins associated with the cytoskeleton (15%). The identity, molecular mass, isoelectric point, and relative concentration of the characterized proteins are described and constitute a partial proteome map of the normal human hippocampus.

Hucolin, a new corticosteroid-binding protein from human plasma with structural similarities to ficolins, transforming growth factor-beta 1-binding proteins.

In order to study the cortisol-binding factors in blood, human plasma was applied to a 11 beta-hydroxy-3-oxo-4-androstene-17 beta-carboxyaminoethylamine-(HACA) 1,4-butanediol diglycidyl ether-Sepharose column. Elution of the column with cortisol buffer produced two protein peaks, the minor peak yielded a protein complex of molecular weight approximately 200 kDa, subsequently termed hucolin. SDS-PAGE analysis under reducing and non-reducing conditions revealed hucolin was a disulphide-linked complex of 35-kDa and 75-kDa subunits. Twenty-five amino acid residues of the N-terminus of the 35-kDa subunit were determined and homology searches revealed an 88% sequence identity with the N-terminal region of beta-ficolin, a transforming growth factor-beta 1 (TGF-beta 1)-binding protein purified from porcine uterus.

Screening for heparin binding variants of antithrombin.

A chromogenic assay for use as a screening test for the identification of antithrombin deficiency is described. The heparin concentration and the incubation time in the assay were optimised specifically to permit the detection of heparin binding defects of antithrombin. The sensitivity of antithrombin assays for the detection of this type of variant was significantly impaired when an incubation time of more than 30 seconds was used. Several commercially available assays recommend a longer incubation time than 30 seconds and therefore some patients with heparin binding defects of antithrombin may not be identified. The assay described here allows heparin binding variants of antithrombin to be identified and distinguished from other types of antithrombin deficiency in a simple two stage procedure.

The incidence of dysfunctional antithrombin variants: four cases in 210 patients with thromboembolic disease.

210 patients, with a history of venous thrombosis, have undergone prothrombotic investigations. In nine cases a consistent deficiency of antithrombin was identified. In five there was a reduction in the plasma antigenic concentration of antithrombin and in a further four cases deficiency was due to the presence of a dysfunctional antithrombin variant. The variants have all been characterized by DNA analysis and in three the mutations have been confirmed by peptide sequencing (antithrombin Basel (41 Pro to Leu). Hamilton (382 Ala to Thr). Cambridge I (384 Ala to Pro) and Cambridge II (384 Ala to Ser). The incidence of antithrombin deficiency in patients with a history of venous thrombosis has previously been quoted at between 2% and 3%: there is no published data available on the incidence of antithrombin variants. In our series 5% of patients who presented before the age of 40 years had antithrombin deficiency, and 2% of the total number of patients investigated had a dysfunctional variant. Our figures indicate that a significant number of cases of antithrombin deficiency are due to dysfunctional variants and that the true incidence of antithrombin deficiency in patients with a history of venous thrombosis is in the order of 5%.

Protein C deficiency and portal thrombosis in liver transplantation in children.

Changes in plasma protein C and antithrombin concentrations after liver transplantation were monitored in fourteen children and a control group of fourteen adults. In the children, there was a persistent deficiency in the plasma concentration of protein C and a less pronounced deficiency in antithrombin during the early postoperative period, causing a hypercoaguable state. A concomitant rise in plasminogen activator inhibitor further increased the risk of thrombosis by inhibiting fibrinolysis. These changes coincided with the peak incidence of portal vessel thrombosis (4-10 days). Replacement of plasma antithrombin, together with heparin, did not prevent portal thrombosis in two of the children. It is concluded that successful prevention will require protein C replacement together with antithrombin supplements up to, but not exceeding, normal plasma activity.