Thomas H. Lampe

Association of an apolipoprotein CII allele with familial dementia of the Alzheimer type

In order to identify the genetic locus responsible for familial dementia of the Alzheimer type (DAT), we are studying 10 families in which DAT appears to be inherited as an autosomal dominant trait. Genotypes for a TaqI restriction fragment length polymorphism (RFLP) at the apolipoprotein CII locus were determined for the following groups: affected and unaffected DAT family members, DAT subjects with no family history of the disease, and normal control subjects. The control group included 103 individuals from our study and 123 from the study of Wallis et al. (Hum. Genet., 68 (1984) 286). The frequency of the TaqI fast (F) allele in the affected familial DAT subjects (0.64 +/- 0.08) differed significantly from that for the control group (0.39 +/- 0.02) (Z = 2.87, P less than 0.005). In contrast, the F-allele frequency for the unaffected family members was 0.31 +/- 0.09, which was similar to that of the combined control group (Z = 0.78, P greater than 0.40). Subsequently, genotypes were determined for two other polymorphisms at the Apo CII locus: a BanI RFLP and a BglI RFLP. For these two polymorphisms, the allele frequencies for the familial DAT subjects differed from the unaffected control groups but the differences were smaller and not statistically significant. These data suggest a previously unrecognized association between the Apo CII TaqI F-allele and familial DAT.

Myoclonus, Seizures, and Paratonia in Alzheimer Disease

Twenty-eight patients with the clinical diagnosis of probable Alzheimer disease (AD) were followed longitudinally until death. The presence of myoclonus, seizures, and paratonia was monitored as part of this process. At autopsy, 22 of the patients met pathologic criteria for AD and 6 had other degenerative neurologic diseases. Myoclonus was present in 55% of the AD patients and none of the non-AD patients. Seizures were present in 64% of the AD patients, and only 17% of the non-AD patients. Paratonia was found frequently in all patient groups. In most patients, symptoms developed late in the course of their illness. The incidence of myoclonus, seizures, and paratonia in our patients was higher than in most previous studies. The reasons for this finding are discussed.

Clinicopathological concordance and discordance in three monozygotic twin pairs with familial Alzheimer’s disease

Aim: Neuropathological examination of both individuals in a monozygotic (MZ) twin pair with Alzheimer’s disease (AD) is rare, especially in the molecular genetic era. We had the opportunity to assess the concordance and discordance of clinical presentation and neuropathology in three MZ twin pairs with AD. Methods: The MZ twins were identified and characterised by the University of Washington Alzheimer’s Disease Research Center. We reviewed the available clinical and neuropathological records for all six cases looking specifically for concordance and discordance of clinical phenotype, neuritic amyloid plaques (NP), neurofibrillary tangles (NFT) and Lewy related pathology (LRP). Results: Discordance in age of onset for developing AD in the MZ twins varied from 4 to 18 years. Clinical presentations also differed between twins. One twin presented with a dementia with Lewy Body clinical syndrome while the other presented with typical clinical AD. Neuropathology within the MZ twin pairs was concordant for NP and NFT, regardless of duration of disease, and was discordant for LRP. This difference was most marked in the late onset AD twin pair. One pair was found to have a mutation in presenilin-1 (PS1) (A79V) with remarkably late onset in a family member. Conclusions: MZ twins with AD can vary considerably in age of onset, presentation and disease duration. The concordance of NP and NFT pathological change and the discordance of LRP support the concept that, in AD, the former are primarily under genetic control whereas the latter (LRP) is more influenced by disease duration and environmental factors. The A79V mutation in PS1 can be associated with very late onset of dementia.

TSH responses to two TRH doses in men with alzheimer's disease

TSH responses to two TRH doses (0.1 mg, 0.5 mg) were determined in 10 men with Alzheimers disease (AD) and in nine healthy matched controls. Maximum change in TSH (delta TSH) and TSH responses over time, analyzed independently for each TRH dose, did not reveal any significant differences between the AD and the normal subjects. Blunted delta TSH responses were an uncommon finding in both groups. Analyses examining the influence of TRH dose on TSH responses revealed significant group differences. In normal subjects, delta TSH responses following the 0.5 mg TRH dose were significantly greater than delta TSH responses following the 0.1 mg TRH dose (p less than 0.01). However, in the AD group, the effects of TRH dose on delta TSH were largely attributable to the exaggerated and outlying TSH responses of one AD subject. For the remaining nine AD subjects, delta TSH responses following the 0.1 mg and 0.5 mg TRH doses were not significantly different (p greater than 0.1). In the analysis of TSH responses over time, the difference between the 0.1 mg and the 0.5 mg TRH-induced TSH responses was significantly smaller in the AD group at several timepoints after infusion compared to the normal subjects.

A proposed classification of familial Alzheimer’s disease based on analysis of 32 multigeneration pedigrees

We propose a classification of familial Alzheimer’s disease (FAD) based on our clinical and pathological analysis of 32 kindreds with multigeneration dementia. The classification can briefly be stated as follows I. Early onset FAD with mean age of onset before 50 years; II. Late onset FAD with mean age of onset after 60 years; III. Intermediate/variable onset FAD; IV. Familial dementia with atypical Alzheimer changes; V. FAD without multigeneration involvement.

Laboratory evaluation for cushing's syndrome in psychiatric patients with cortisol nonsuppression following the overnight dexamethasone suppression test

Laboratory tests used for the differential diagnosis of Cushings syndrome have infrequently been employed in investigations of psychiatric patients who demonstrate hypothalamic-pituitary-adrenal (HPA) overactivity, and these laboratory procedures have not previously been applied for the specific purpose of further evaluating the endocrine function of psychiatric patients with serum cortisol nonsuppression following the standard 1-mg overnight Dexamethasone Suppression Test (DST). Low-dose (4 mg/48 hr) and high-dose (16 mg/48 hr) DSTs were administered to 10 psychiatric patients who exhibited cortisol nonsuppression after the overnight DST. Patients all had normal suppression to both the low-dose and high-dose tests. HPA overactivity in these patients was thus not sufficient to meet laboratory criteria for the diagnosis of Cushings syndrome. Study results suggest that psychiatric patients with abnormal cortisol suppression following the 1-mg overnight DST are likely to have normal responses when assessed by standard laboratory protocols used for the diagnosis of Cushings syndrome.

The frequency of C4B variants of complement in familial and sporadic Alzheimer disease.

Abstract.A previous study reported an unexpected increased frequency of the uncommon C4B2 allele of complement in a group of patients with senile dementia of the Alzheimer type. We compared the frequency of various C4B types in 25 patients with familial Alzheimer dementia (AD), 22 patients with sporadic AD, and 360 control individuals. Neither Alzheimer group showed any significant increase or decrease in the frequency of C4B alleles compared with controls. We were unable to confirm any association between AD and the C4B2 allele.

Lack of detectable radiation hypersensitivity in lymphoblastoid cells from multiple pedigrees of familial Alzheimer disease

Recent reports suggest that cultivated nonneuronal cells from individuals with Alzheimer disease (AD) and other specific hereditary neuro-degenerative disorders show hypersensitivity to DNA-damaging agents such as x-rays and radiomimetic chemicals. The hypothesis proposed is that a number of chronic neurologic degenerations, including AD, may be the result of accumulation of damaged DNA, resulting from a defect in DNA repair. We investigated this hypothesis by evaluating cells from individuals from pedigrees of familial Alzheimer disease (FAD) for hypersensitivity to x-irradiation. Sensitivity was assayed by viability measured by trypan blue dye exclusion and micronucleus formation. We tested B-lymphoblastoid cell lines from nine patients and nine unaffected family members from pedigrees with FAD, three unrelated controls, three ataxia telangiectasia (AT) patients, and three Down syndrome individuals. The AT cell lines showed the expected reduced viability and increased micronucleus formation after x-ray treatment. The FAD and control lines showed marked heterogeneity with both assays. There was no significant differences between the FAD patients and controls. The wide variability in the response of cell lines from controls and patients indicates the need for more sensitive assays for detection of radiation sensitivity in cells from various neurologic disorders.

CHARACTERISTICS OF FAMILIAL ALZHEIMER??S DISEASE IN NINE KINDREDS OF VOLGA GERMAN ANCESTRY

We report the clinical and neuropathological manifestations of Alzheimers disease (AD) in nine kindreds of German ancestry all originating from the same two adjacent villages on the West bank of the Volga River. There have been 89 known demented persons (53 male, 36 female). Mean age of onset is 57.6 +/- 8.4 years with a range of 40 to 84. Mean age at death is 66.5 +/- 7.6 years with a range of 50 to 80. Mean disease duration is 10.3 +/- 4.8 years with a range of 3 to 23. Detailed medical records were available on 50 individuals. Of these, 24% had a seizure, 72% language disturbance, 36% rigidity, 16% tremor and 12% myoclonus. There were 15 autopsies on demented persons from 6 of the kindreds. One brain suggested Creutzfeldt-Jakob disease (CJD) in a woman with the typical clinical course. The remaining 14 brains showed typical neuropathological characteristics of AD including neuritic amyloid plaques, neurofibrillary tangles, amyloid angiopathy and granulovacuolar change. Amyloid plaques were also seen in the cerebellum in all but one brain in which this region was available for review. Autopsy material from five brains in four families has been stained with antibody directed against the amyloid peptide; in all cases, the neuritic plaques stained positively. Many of the families share common surnames. It is likely that these Volga German kindreds carry the same genetic mutation leading to Alzheimers disease; and thus, they are a valuable resource for genetic investigations of AD. Thus far, the disease in these kindreds does not show close linkage to either the D21S1 or beta amyloid gene loci on chromosome 21.