4p16.3 haplotype modifying age at onset of Huntington disease.

Huntington disease (HD) is caused by an expanded CAG repeat sequence in the HD gene. Although the age at onset is correlated to the CAG repeat length, this correlation only explains approximately half of the variation in onset age. Less variation between siblings indicates that the variation is, in part, explained by genetic modifiers. We analyzed polymorphic loci within or close to the HD gene on the HD chromosome in Danish HD patients. We found one specific haplotype segregating with later age at onset, compared with patients with similar CAG repeat length and another haplotype. The nine Danish families in the study carrying this haplotype most likely have a common founder. Several of the polymorphic loci displayed alleles that may be specific to the late-onset haplotype, implicating that from this study we cannot determine which of the loci tested (or other polymorphic loci in this chromosomal area) do in fact contain genetic modifiers of age at onset.

Double-blind crossover trial of gabapentin in SPG4-linked hereditary spastic paraplegia.

Patients with hereditary spastic paraplegia (HSP) are often treated with antispastic drugs to relieve symptoms but documentation is lacking. In this study, gabapentin was tested in a double-blind crossover trial on a group of patients with HSP and linkage to the SPG4 locus. There was no difference between periods with gabapentin and placebo treatment in clinical assessment, self-reported parameters or paired transcranial magnetic stimulation evaluation of motor cortical excitability.

Molecular and behavioral analysis of the R6/1 Huntington's disease transgenic mouse.

Transgenic mice expressing exon 1 of the human Huntington's disease (HD) gene carrying a 115 CAG repeat (line R6/1) are characterized by a neurologic phenotype involving molecular, behavioral and motor disturbances. We have characterized the R6/1 to establish a set of biomarkers, which could be semi-quantitatively compared. We have measured motor fore- and hindlimb coordination, fore- and hindpaw footprinting, general activity and anxiety, feetclasping, developmental instability. Molecular investigations involved measurements of cannabinoid receptor 1 mRNA, met-enkephalin peptide, dopamine and cyclic AMP-regulated phosphoroprotein 32 kDa and neuronal inclusions. Molecular and behavioral testing was performed on female hemizygotic R6/1 transgenic mice and female wildtype littermates between 6 and 36 weeks of age. We show that the cannabinoid receptor 1 receptor is severely and rapidly downregulated in the R6/1 mouse between the 8(th) to the 10(th) week of age. At 14 weeks of age the first transgenic mice showed a behavioral phenotype measured by feetclasping. However, there was great variation between the individual animals. At 11 weeks of age the mice demonstrated progressively increasing developmental instability as measured by fluctuating asymmetry. Weight differences were evident by 22 weeks of age. Mice tested at 23 and 24 weeks of age showed significant impairments in open field and plus-maze analysis respectively. We observed no significant abnormalities in stride length of the R6/1 mouse model. As the analyzed parameters are easily detected and measured, the R6/1 mouse appears to be a good model for evaluating new drugs or types of therapy for HD.

Increased intracortical facilitation in patients with autosomal dominant pure spastic paraplegia linked to chromosome 2p.

There are at least seven clinically indistinguishable but genetically different types of autosomal dominant pure spastic paraplegia (ADPSP). In this study we investigated electrophysiological characteristics in patients with ADPSP linked to chromosome 2p (SPG4). Twelve patients from six different families with ADPSP linked to chromosome 2p and 15 control persons were included. Electromyography (EMG), motor and sensory nerve conduction, and motor evoked potentials using single and paired transcranial magnetic stimulation (PTMS) was performed. From the peripheral nervous system we found signs of motor and sensory axonal neuropathy. Motor evoked potentials disclosed greatly reduced corticospinal tract conduction velocity and amplitude of evoked potentials to the lower extremities indicating that the very marked spasticity predominantly seems to rely on dysfunction of the fast conducting axons of the pyramidal tract. PTMS showed an increased intracortical facilitation (ICF), which may reflect an impaired function of gamma-aminobutyric acid (GABA)-controlled interneuronal circuits in the motor cortex, alternatively an increased glutamatergic transmission or a compensatory recruitment of a larger number of neurones with corticospinal projections.

BRCA1 and BRCA2 mutation status and cancer family history of Danish women affected with multifocal or bilateral breast cancer at a young age.

INTRODUCTION: A small fraction of breast cancer is the result of germline mutations in the BRCA1 and BRCA2 cancer susceptibility genes. Mutation carriers frequently have a positive family history of breast and ovarian cancer, are often diagnosed at a young age, and may have a higher incidence of double or multiple primary breast tumours than breast cancer patients in general. OBJECTIVES: To estimate the prevalence and spectrum of BRCA1 and BRCA2 mutations in young Danish patients affected with bilateral or multifocal breast cancer and to determine the relationship of mutation status to family history of cancer. SUBJECTS: From the files of the Danish Breast Cancer Cooperative Group (DBCG), we selected 119 breast cancer patients diagnosed before the age of 46 years with either bilateral (n=59) or multifocal (n=61) disease. METHODS: DNA from the subjects was screened for BRCA1 and BRCA2 mutations using single strand conformation analysis (SSCA) and the protein truncation test (PTT). Observed and expected cancer incidence in first degree relatives of the patients was estimated using data from the Danish Cancer Registry. RESULTS: Twenty four mutation carriers were identified (20%), of whom 13 had a BRCA1 mutation and 11 carried a BRCA2 mutation. Two mutations in BRCA1 were found repeatedly in the material and accounted for seven of the 24 (29%) mutation carriers. The mutation frequency was about equal in patients with bilateral (22%) and multifocal breast cancer (18%). The incidence of breast and ovarian cancer was greatly increased in first degree relatives of BRCA1 and BRCA2 mutation carriers, but to a much lesser degree in relatives of non-carriers. An increased risk of cancer was also noted in brothers of non-carriers. CONCLUSIONS: A relatively broad spectrum of germline mutations was observed in BRCA1 and BRCA2 and most of the mutations are present in other populations. Our results indicate that a diagnosis of bilateral and multifocal breast cancer is predictive of BRCA1 and BRCA2 mutation status, particularly when combined with information on the patients' age at diagnosis and family history of breast/ovarian cancer.

Clinically overt hereditary hemochromatosis in Denmark 1948-1985: epidemiology, factors of significance for long-term survival, and causes of death in 179 patients.

The object was to analyze, in a nationwide survey, the incidence and course of hereditary hemochromatosis in relation to the degree of iron overload and the presence of organ damage. The study included 179 Danish Caucasian patients with clinically overt hemochromatosis diagnosed between 1948 and 1985. A cohort of 158 patients was followed for a median of 8.5 years (range: 0.2-29.5). From 1951 to 1975, the yearly relative incidence rate was constant: 0.58/100,000 persons >20 years of age. From 1981 to 1985, the yearly relative incidence rate rose to 1.40/100,000 persons >20 years of age. Survival was reduced in the entire series when compared with a matched control population ( p<0.0001). There was a steady increase in survival from 1948 to 1985 ( p<0.002). Survival was significantly reduced in patients with liver cirrhosis and/or diabetes mellitus ( p<0.01). In contrast, survival in patients without cirrhosis or diabetes was similar to rates expected. Survival in patients with arthropathy was higher than in patients without joint affection ( p<0.004). Patients adequately treated with phlebotomy ( n=66) had a higher survival than inadequately treated patients ( n=62; p<0.0001). Adequately treated patients with cirrhosis and/or diabetes had better survival than inadequately treated patients with similar organ damage ( p<0.001). The main causes of death were hepatic failure due to cirrhosis (32.0%) and cirrhosis with liver cancer (23.1%). Sharpened diagnostic awareness has improved early diagnosis and increased the diagnostic frequency of clinical hemochromatosis. Adequate phlebotomy treatment was the major determinant of survival and markedly improved prognosis. Early detection and treatment of this common iron overload disorder is crucial and can completely prevent any excess mortality caused by hemochromatosis.

Significantly lower incidence of cancer among patients with Huntington disease: An apoptotic effect of an expanded polyglutamine tract?

BACKGROUND: The authors of this study have previously observed that cancer is rarely reported on the death certificates of patients with Huntington disease. This study was undertaken to investigate whether this disorder is associated with a lower incidence of cancer. METHODS: A total of 694 patients with Huntington disease who had survived at least to age 45 years during the period 1943-1993, and 695 individuals at risk and at least age 55 years during the same period, were selected from the Danish Huntington Disease Registry. The occurrence of cancer was determined from the files of the Danish Cancer Registry and compared with national incidence rates for various categories of tumors. RESULTS: The overall incidence of cancer was significantly lower among patients with Huntington disease, but not among their healthy relatives. The standardized incidence ratio for the Huntington patients was 0.6 with a 95% confidence interval of 0.5-0.8. The lower incidence was seen for cancers of all major tissues and organs except the buccal cavity and the pharynx. CONCLUSIONS: The lower incidence of cancer among patients with Huntington disease seems to be related to intrinsic biologic factors. One explanation may be that the modified protein, huntingtin, encountered in Huntington disease protects against cancer by inducing or increasing the rate of naturally occurring programmed cell death in preneoplastic cells.

The prevalence and characteristics of migraine in twins from the general population.

We examined whether prevalence, age at onset, and cessation of migraine without aura and migraine with aura are different among twins and singletons. The study population was recruited from the population-based New Danish Twin Register and comprised 2026 monozygotic and 3334 same-sex dizygotic twins born during 1953 to 1960. A simple questionnaire was used to screen for migraine. Twin pairs with at least one twin with possible migraine were interviewed by telephone by two physicians. A total of 1136 twin pairs were included in the telephone interviews. The criteria of the International Headache Society were used for diagnosis. The questionnaire response rate was 87%, and the telephone interview participation rate was 90%. Of the 715 migraineurs, 498 had migraine without aura, 264 had migraine with aura, and 47 had both migraine with and without aura. The lifetime prevalence, age at onset, and cessation of migraine with and without aura did not differ in monozygotic and dizygotic twins. Males and females had a lifetime prevalence of migraine without aura of 7% and 19%, respectively. The female preponderance of migraine without aura was first apparent after aged 14 years; this may be related to an influence of female hormones. The lifetime prevalence of migraine with aura was 7% in males and 8% in females. The observed and expected number of those with both migraine with and without aura was not significantly different, suggesting that migraine without aura and migraine with aura are distinct types of migraine. Males with migraine without aura had a significantly lower mean age at onset than females with migraine without aura (16.5 years versus 21.5 years), while males and females with migraine with aura had similar ages at onset (20.8 years versus 21.8 years). About 20% of the twins had ceased having attacks of migraine with or without aura. More males than females with onset of migraine without aura before aged 15 years had ceased having attacks. The prevalence of migraine without aura and migraine with aura in twins was similar to the prevalence in the general population. Being a twin did not affect age at onset or cessation of migraine. Previous observations on differences of migraine without aura and migraine with aura regarding gender was confirmed.

Mitotic and meiotic instability of the CAG trinucleotide repeat in spinocerebellar ataxia type 1.

Spinocerebellar ataxia type 1 (SCA1) is an autosomal, dominantly inherited neurodegenerative disease caused by an unstable CAG trinucleotide repeat expansion in the ataxin-1 gene located on chromosome 6p22-p23. The expanded CAG repeat is unstable during transmission, and a variation in the CAG repeat length has been found in different tissues, including sperm samples from affected males. In order further to examine the mitotic and meiotic instability of the (CAG)n stretch we have performed single sperm and low-copy genome analysis in SCA1 patients and asymptomatic carriers. A pronounced variation in the size of the expanded allele was found in sperm cells and peripheral blood leucocytes, with a higher degree of instability seen in the sperm cells, where an allele with 50 repeat units was contracted in 11.8%, further expanded in 63.5% and unchanged in 24.6% of the single sperm analysed. We found a low instability of the normal alleles; the normal alleles from the individuals carrying a CAG repeat expansion were significantly more unstable than the normal alleles from the control individuals (P<0.001), indicating an interallelic interaction between the expanded and the normal alleles.

Crime in Huntington's disease: a study of registered offences among patients, relatives, and controls.

OBJECTIVES: Criminal behaviour has been described as a problem in Huntington's disease, but systematic studies including control groups have been missing. Based on information from Danish registries, rates and types of crime committed by patients with Huntington's disease, non-affected relatives, and controls were studied. METHODS: 99 males and 151 females with Huntington's disease were compared with 334 non-affected first degree relatives (134 men and 200 women) and to matched control groups as to frequencies and types of registered criminal convictions. Due to specific age criteria, the group of relatives comprised only about 9% carriers of the gene coding for Huntington's disease. RESULTS: In male patients, crime rates were significantly increased compared with first degree relatives (RR=2.8) and controls (RR=2.3). All types of crime occurred more often in male patients; more severe crimes (murder, rape, arson) were not reported. Rates of drunken driving were significantly increased compared with relatives (RR=3.8) and controls (RR=7.1). Crime rates were neither increased in female patients nor in male and female first degree relatives. CONCLUSION: The results indicate increased prevalence of criminal behaviour in males carrying the gene for Huntington's disease. The crimes committed seem to be of relatively minor severity and are probably closely linked to the personality changes often seen as a result of the disease process, although depressive reactions to the disease, with secondary alcohol misuse, may also play a part. Environmental and familial factors shared by patients and non-affected at risk persons seem to be of less aetiological importance.

Machado-Joseph disease in three Scandinavian families.

Machado-Joseph disease (MJD) is an autosomal dominantly inherited neurodegenerative disorder characterized by varying age of onset and pronounced phenotypic heterogeneity. The clinical core features include gait ataxia, external ophthalmoplegia, nystagmus, and bulging eyes. Recently, Kawagushi et al. (1994) cloned the MJD1 gene on chromosome 14 and MJD turned out to be the fifth neurodegenerative disease caused by an unstable CAG repeat expansion. We have studied two large Danish families and one Norwegian family with MJD. Three features not previously associated with MJD are reported: dementia, generalized muscle and joint pain, and in one case neuropathological examination revealed atrophy of the inferior olives. We found a significant inverse correlation between age of onset and the length of the CAG repeat expansion, and anticipation is described through four succeeding generations. Instability of the CAG repeat expansion was most pronounced at paternal transmission.

Autosomal dominant pure spastic paraplegia: a clinical, paraclinical, and genetic study.

OBJECTIVES: At least three clinically indistinguishable but genetically different types of autosomal dominant pure spastic paraplegia (ADPSP) have been described. In this study the clinical, genetic, neurophysiological, and MRI characteristics of ADPSP were investigated. METHODS: Sixty three at risk members from five families were clinically evaluated. A diagnostic index was constructed for the study. Microsatellite genotypes were determined for chromosomes 2p, 14q, and 15q markers and multipoint linkage analyses were performed. Central motor conduction time studies (CMCT), somatosensory evoked potential (SSEP) measurement, and MRI of the brain and the total spinal cord were carried out in 16 patients from four families. RESULTS: The clinical core features of ADPSP were homogeneously expressed in all patients but some features were only found in some families and not in all the patients within the family. In two families non-progressive "congenital" ADPSP was seen in some affected members whereas adult onset progressive ADPSP was present in other affected family members. As a late symptom not previously described low backache was reported by 47%. Age at onset varied widely and there was a tendency for it to decline in successive generations in the families, suggesting anticipation. Genetic linkage analysis confined the ADPSP locus to chromosome 2p21-p24 in the five families. The lod scores obtained by multipoint linkage analysis were positive with a combined maximum lod score of Z=8.60. The neurophysiological studies only showed minor and insignificant prolongation of the central motor conduction time and further that peripheral conduction and integrity of the dorsal columns were mostly normal. Brain and the total spinal cord MRI did not disclose any significant abnormalities compared with controls. CONCLUSIONS: ADPSP linked to chromosome 2p21-p24 is a phenotypic heterogeneous disorder characterised by both interfamilial and intrafamilial variation. In some families the disease may be "pure" but the existence of "pure plus" families is suggested in others. The neurophysiological and neuroimaging investigations did not show any major abnormalities.

MRI of autosomal dominant pure spastic paraplegia.

We examined 16 patients with autosomal dominant pure spastic paraplegia (HSP) and 15 normal controls matched for age and sex using MRI of the brain and spinal cord. Images were assessed qualitatively by two independent radiologists, blinded to the clinical diagnosis. Areas of the brain and corpus callosum on one midsagittal slice and the area of the brain on one axial slice were measured and a "corpus-callosum index" expressing the size of the corpus callosum relative to that of the brain was calculated. Cross-sectional areas and anteroposterior and transverse diameters of the spinal cord at the levels of C 2, C 5, T 3, T 6, T 9 and T 11 were measured. No significant differences between patients and controls were found on qualitative evaluation of the images. The patients had a significantly smaller corpus callosum and "corpus-callosum index" than controls. This finding, not reported previously, might indicate that the disease process in pure HSP is not confined to the spinal cord. The anteroposterior diameters of the spinal cord at T 3 and T 9 were significantly smaller in patients than in controls. This might correspond to the degeneration of the pyramidal tracts and the dorsal columns described at neuropathological examination.

CAG repeat expansion in autosomal dominant pure spastic paraplegia linked to chromosome 2p21-p24.

CAG repeat expansions have been identified as the disease-causing dynamic mutations in the coding regions of genes in several dominantly inherited neurodegenerative disorders, including spinobulbar muscular atrophy, Huntington's disease, dentatorubral-pallidoluysian atrophy, spinocerebellar ataxia type 1, 2 and 6 and Machado-Joseph disease. The CAG repeat expansions are translated to elongated polyglutamine tracts and an increased size of the polyglutamine tract correlates with anticipation, the cardinal feature, seen in all these diseases. Autosomal dominant pure spastic peraplegia (ADPSP) is a degenerative disorder of the central motor system clinically characterized by slowly progressive and unremitting spasticity of the legs, hyperreflexia and Babinski's sign. Like the established CAG repeat diseases ADPSP is characterized by both inter- and intrafamilial variation and anticipation. Using the Repeat Expansion Detection (RED) method, we have analyzed 21 affected individuals from six Danish families with the disease linked to chromosome 2p21-p24. We found that 20 of 21 affected individuals showed CAG repeat expansions versus two of 21 healthy spouses, demonstrating a strongly statistically significant association between the occurrence of the repeat expansion and the disease (Fisher's test, P < 10(-5)) suggesting that a CAG repeat expansion is involved presumably as a dynamic mutation in ADPSP linked to chromosome 2p21-p24. The size of the expansion is estimated to be > or = 60 CAG repeat copies in the affected individuals. The CAG repeat expansion is very likely translated and expressed as indicated by the detection of a polyglutamine-containing protein in an ADPSP patient.

Migraine without aura and migraine with aura are distinct clinical entities: a study of four hundred and eighty-four male and female migraineurs from the general population.

The clinical characteristics of migraine without aura (MO) and migraine with aura (MA) were compared in 484 migraineurs from the general population. We used the criteria of the International Headache Society. The lifetime prevalence of MO was 14.7% with a M:F ratio of 1:2.2; that of MA was 7.9% with a M:F ratio of 1:1.5. The female preponderance was significant in both MO and MA. The female preponderance was present in all age groups in MA, but was first apparent after menarche in MO, suggesting that female hormones are an initiating factor in MO, but not likely so in MA. The age at onset of MO followed a normal distribution, whereas the age at onset of MA was bimodally distributed, which could be explained by a composition of two normal distributions. The estimated separation between the two groups of MA was at age 26 years among the females and age 31 years among the males. The observed number of persons with co-occurrence of MO and MA was not significantly different from the expected number. The specificity and importance of premonitory symptoms are questioned, but prospective studies are needed. Bright light was a precipitating factor in MA, but not in MO. Menstruation was a precipitating factor in MO, but not likely in MA. Both MO and MA improved during pregnancy. The clinical differences indicate that MO and MA are distinct entities.

The family history of migraine. Direct versus indirect information.

Migraine assessed by proband report was evaluated in a family study of migraine. A clinical interview of spouses and first-degree relatives by a physician was used as an index of validity. The operational diagnostic criteria of the International Headache Society were used. Of the 378 probands from the general population, 126 had migraine without aura, 127 had migraine with aura, 17 had both migraine without aura and migraine with aura and 108 had never had migraine. Spouses (n = 229) and first-degree relatives (n = 1109) were included in the analyses. Sensitivity, specificity, predictive values and chance-corrected agreement rate for the diagnosis of migraine were 49%, 93%, 81% (PVpos), 77% (PVneg) and 0.47, respectively. The corresponding values for migraine without aura were 58%, 87%, 63% (PVpos), 84% (PVneg) and 0.46 respectively, while the values for migraine with aura were 52%, 88%, 61% (PVpos), 83% (PVneg) and 0.42, respectively. Migraine assessed by proband report is not satisfactory for diagnosing migraine in relatives, since the number of affected relatives is highly underestimated. Our results emphasize the necessity of a clinical interview of the relatives in family studies of migraine.

Correlation between magnitude of CAG repeat length alterations and length of the paternal repeat in paternally inherited Huntington's disease.

An increasing number of diseases are being found to be due to elongation of specific trinucleotide repeat sequences. Inverse correlation between the age at onset and the length of the repeat has been found in most of these. The elongated CAG repeat causing Huntington's disease is highly unstable when inherited from an affected father. In this study we found an average parent-to-offspring difference of +0.08 repeat units in maternally inherited repeats, significantly less than the average difference of +2.92 repeat units with paternal transmission. Large repeat expansions, of more than 5 repeat units, were seen only in paternally inherited cases. With paternal transmission the magnitude of repeat length alterations was directly correlated to increasing paternal repeat length. Increasing variation in repeat length among siblings was correlated to increasing average repeat length in the sibship in both maternally and paternally inherited HD. Comparison of the magnitude of repeat length alterations to parental age at the time of birth of the offspring showed no correlation.

Relationship between genotype, assessed by HLA typing, and phenotypic expression of iron status markers in families of 29 probands with hereditary haemochromatosis.

The purpose of this pedigree study, comprising 29 families with hereditary haemochromatosis (HH), was to evaluate the relationship between the genotype (G), based on HLA typing, and the phenotype, based on measurement of iron status markers (serum transferrin saturation and serum ferritin). Due to tight linkage between the HH locus and the HLA-A locus, 172 relatives of the 29 unrelated probands could be assigned into three groups: G0 who were considered to be normal (n = 53), G1 who were considered to be heterozygotes (n = 105), and G2 who were considered to be homozygotes (n = 14), according to whether they had no, one or two HLA haplotypes in common with the proband. A high serum transferrin saturation (> 60%) was present in 8/14 = 57.1% of the homozygotes, in 11/105 = 10.5% of the heterozygotes, and in 0/53 = 0% of the normals. Of the homozygotes, 8/14 = 57.1% had preclinical disease, 4/14 = 28.6% had clinically overt iron overload, while 2/14 = 14.3% had normal iron status markers. None of the heterozygotes had clinical evidence of iron overload. Analysis of HLA alleles and iron status markers suggested that 11/105 = 10.5% subjects initially classified as heterozygotes (G1) according to HLA typing should be reclassified as homozygotes because of abnormal iron status markers, explained by either: homozygous x heterozygous (n = 7) or heterozygous x heterozygous (n = 2) matings, HLA recombination (n = 1) or strongly abnormal iron status markers (n = 1).(ABSTRACT TRUNCATED AT 250 WORDS)

Familial occurrence of Hirschsprung's disease.

We assessed the familial occurrence of Hirschsprung's disease from 224 probands born in Denmark after 1959. Probands who were still alive received a mailed questionnaire, and medical reports for the probands and their relatives with suspected Hirschsprung's disease were examined. The diagnosis of Hirschsprung's disease required a histologically verified biopsy or surgical colonic specimens, and exclusion of a secondary causes for Hirschsprung's disease. Familial occurrence was seen in 11 families. Ten first-degree, two third-degree and one fifth-degree relatives had Hirschsprung's disease. Both short segment agangliosis (the sigmoid colon or below) and long segment agangliosis (above the sigmoid colon) occurred in five of the 11 families, implying that the etiology of Hirschsprung's disease with short and long segment agangliosis is the same. Compared with the general population, the first-degree relatives of the 224 probands had a minimum of a 93-fold increased risk of Hirschsprung's disease. This strongly suggests that genetic factors play a role in Hirschsprung's disease.