Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Genetic Load”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources

Non-psychotic disorders in the families of process schizophrenics.

The present study was designed to test the hypothesis of "schizophrenic spectrum" disorders. The families of 60 process schizophrenics were systematically interviewed with structured interview forms, and evaluated for psychiatric illness according to strict diagnostic criteria. The interviewed persons were then separated into two groups for comparative analysis according to a positive (FH+) or negative (FH-) family history for schizophrenia. The frequencies of affective disorder and all non-psychotic conditions did not differ to a convincingly significant degree between the two groups. Our data thus fail to support the "schizophrenic spectrum" hypothesis in which neurosis and sociopathy occur as a consequence of a genetic loading for schizophrenia.?

Adult↗

Familial-genetic and reproductive epidemiology of schizophrenia in rural Ireland: age at onset, familial morbid risk and parental fertility.

Among all ascertainable cases of DSM IIIR schizophrenia within an unusually homogeneous region of rural Ireland, family history information was sought from multiple sources. Morbid risk for schizophrenia among probands' first degree relatives was 6.1% and did not differ between male (6.5%) and female (5.5%) probands; risk among probands' siblings (8.3%) exceeded that among their parents (1.4%), with only 2% of male and 31% of female probands being themselves married. Both age at onset <25 and having >7 siblings were associated with elevated morbid risk, particularly among relatives of male probands (11.9% vs. 2.2% and 11.8% vs. 3.7%, respectively). Increased fertility particularly among parents of male patients with high familial-genetic loading may contribute to perpetuation of the disorder in the face of those patients' own extremely low fecundity.

Adult↗

Seasonal cyclothymia to seasonal bipolar affective disorder: a double switch after stroke.

The appearance of bipolar affective disorder after stroke depends on the presence of two factors: a predisposing factor of either genetic loading or subcortical atrophy, and a lesion of specific corticolimbic pathways involving the right hemisphere. Whether cyclothymia and seasonal affective disorder further predispose to poststroke affective disorder is not clear. A case is described which highlights these issues. The aetiological factors, pathophysiology, and diagnosis are discussed.

Aged↗

Familial schizophrenia and treatment response.

Thirty-nine patients with chronic schizophrenia for whom hospitalization was clinically indicated received haloperidol for 4 to 6 weeks in a standardized dose schedule. Responders were compared with nonresponders for family history, baseline symptom factors, and ventricle-brain ratio (VBR). The lifetime risk for schizophrenia spectrum disorders was higher among first-degree relatives of nonresponders than among first-degree relatives of responders. Treatment responders had higher baseline scores on the factors of activation and hostile-suspiciousness, but the groups did not differ in any other baseline symptom factor or in VBR. The authors suggest that there is an association between failure to respond to drugs and genetic loading for schizophrenia spectrum disorders.

Adolescent↗

Depressive symptoms and family history in seasonal and nonseasonal mood disorders.

OBJECTIVE: The authors' goal was to compare the symptoms and family history of seasonal affective disorder with those of nonseasonal mood disorders. METHOD: From a subspecialty mood disorders clinic, 34 patients with major depression, seasonal pattern (seasonal affective disorder), diagnosed with DSM-III-R criteria, were matched in age, sex, and diagnostic subtype (recurrent unipolar, bipolar I, or bipolar II) to 34 patients with nonseasonal mood disorders. Data on symptoms during the most recent depressive episode were obtained by chart review and compared by using chi-square tests. Family history data for first-degree relatives of patients with seasonal and nonseasonal mood disorders were gathered by using the family history method, and diagnoses were based on Family History Research Diagnostic Criteria. RESULTS: Patients with seasonal affective disorder reported significantly more hypersomnia, hyperphagia, and weight gain and reported less suicidal ideation and morning worsening of mood than the patients with nonseasonal mood disorders. No differences were found in family histories of mood disorders, other psychiatric disorders, and any psychiatric disorder between the groups with seasonal versus nonseasonal mood disorders. Alcoholism was found more frequently in the relatives of the patients with seasonal affective disorder. CONCLUSIONS: Differences in symptoms between seasonal and nonseasonal mood disorders provide some support for seasonal affective disorder as a diagnostic subtype of mood disorders. However, the genetic loading for mood disorders (of unspecified seasonality), as determined by the family history method, is similar for seasonal and nonseasonal mood disorders.

Adult↗

Structural brain magnetic resonance imaging of limbic and thalamic volumes in pediatric bipolar disorder.

BACKGROUND: Youths with bipolar disorder are ideal for studying illness pathophysiology given their early presentation, lack of extended treatment, and high genetic loading. Adult bipolar disorder MRI studies have focused increasingly on limbic structures and the thalamus because of their role in mood and cognition. On the basis of adult studies, the authors hypothesized a priori that youths with bipolar disorder would have amygdalar, hippocampal, and thalamic volume abnormalities. METHOD: Forty-three youths 6-16 years of age with DSM-IV bipolar disorder (23 male, 20 female) and 20 healthy comparison subjects (12 male, eight female) similar in age and sex underwent structured and clinical interviews, neurological examination, and cognitive testing. Differences in limbic and thalamic brain volumes, on the logarithmic scale, were tested using a two-way (diagnosis and sex) univariate analysis of variance, with total cerebral volume and age controlled. RESULTS: The subjects with bipolar disorder had smaller hippocampal volumes. Further analysis revealed that this effect was driven predominantly by the female bipolar disorder subjects. In addition, both male and female youths with bipolar disorder had significantly smaller cerebral volumes. No significant hemispheric effects were seen. CONCLUSIONS: These findings support the hypothesis that the limbic system, in particular the hippocampus, may be involved in the pathophysiology of pediatric bipolar disorder. While this report may represent the largest MRI study of pediatric bipolar disorder to date, more work is needed to confirm these findings and to determine if they are unique to pediatric bipolar disorder.

Adolescent↗

Age, parasuicide and problem drinking.

The contribution from genetic loading in a series of male parasuicidal patients with early onset alcohol problem was found to be of less importance than the nurturance factor of separation from father during childhood. Behavioural patterns in this younger onset group were significantly more antisocial than those in the older onset group.

Adult↗

Environment versus genetics in autoimmunity: a geneticist's perspective.

Both environmental as well as genetic factors have been documented to contribute to autoimmunity, as is evident from the accompanying articles in this journal. This raises an important question - which of these two elements plays a more important role in the genesis of autoimmunity? This report encapsulates a geneticist's perspective on this interesting question. Though lupus is used as an example in this essay, the proposed model is envisaged to operate in other autoimmune diseases as well.

Animals↗

The development of sex differences in infantile autism.

Seventy-five autistic children, 52 males and 23 females, were admitted to the Iowa Autism Programme over a 3-year period. An overall male-female ratio of 2.26:1 was found, but in the patients with IQs less than 50, the ratio was 1.31:1. When IQ and receptive language functioning were considered together, significantly more females than males showed a more deviant form of autism. Autistic females were more seriously affected than autistic males; and more autistic females than males had IQs of less than 50 and evidence of cerebral dysfunction. However, when autistic males and females were closely matched in chronological age and receptive language functioning, the males and females were equally impaired in cognitive and perceptual-motor abilities. The findings suggest that the overall greater degree of morbidity in autistic females was accounted for by a significantly greater proportion of autistic males affected with a mild form of autism, whereas a significantly greater proportion of autistic females were affected with a more deviant form of autism. The findings were linked to the hypothesis of differential genetic loading in males and females.

Adolescent↗

Affective disorders and cerebral vascular disease.

Empirical studies have recently demonstrated that major and minor depressive disorders occur in 30-50% of stroke patients, and last more than one year without treatment, although they do respond to tricyclic antidepressants. These mood disorders are not strongly associated with severity of impairment, demographic characteristics, social supports or prior personal history, but major depression is often strongly associated with left frontal or left basal ganglia lesions and pre-existing subcortical atrophy. While the aetiology of these mood disorders remains unknown, serotonergic or noradrenergic dysfunction may play a role. Mania is a rare complication of stroke: the clinical presentation and response to treatment are usually the same as mania without brain injury. Post-stroke mania is strongly associated with both a right hemisphere lesion in a limbic-connected area and a second predisposing factor, such as genetic loading for affective disorder, pre-existing subcortical atrophy or seizure disorder. This disorder may be mediated through frontal lobe dysfunction. The lesion method represents a potentially fruitful technique for investigating the mechanisms of affective disorder.

Bipolar Disorder↗

Age at onset, sex, and familial psychiatric morbidity in schizophrenia. Camberwell Collaborative Psychosis Study.

BACKGROUND: Although a genetic component in schizophrenia is well established, it is likely that the contribution of genetic factors is not constant for all cases. Several recent studies have found that the relatives of female or early onset schizophrenic patients have an increased risk of schizophrenia, compared to relatives of male or late onset cases. These hypotheses are tested in the current study. METHOD: A family study design was employed; the probands were 195 patients with functional psychosis admitted to three south London hospitals, diagnosed using Research Diagnostic Criteria (RDC), and assessed using the Present State Examination (PSE). Information on their relatives was obtained by personal interview of the mother of the proband, and from medical records. Psychiatric diagnoses were made using Family History-Research Diagnostic Criteria (FH-RDC), blind to proband information. RESULTS: There was a tendency for homotypia in the form of psychosis within families. The lifetime risk of schizophrenia in the first degree relatives of schizophrenic probands, and the risk of bipolar disorder in the first degree relatives of bipolar probands, were 5-10 times higher than reported population risks. Relatives of female and early onset (< 22 years) schizophrenic probands had higher risk of schizophrenia than relatives of male and late onset schizophrenic probands. However, this effect was compensated in part by an excess of non-schizophrenic psychoses in the relatives of male probands. CONCLUSIONS: These results suggest a high familial, possibly genetic, loading in female and early onset schizophrenia, but do not resolve the question of heterogeneity within schizophrenia.

Adult↗

On the discriminative validity of a family history of problem drinking index with a national sample of young adults.

OBJECTIVE: This study used data from the National Longitudinal Survey of Youth (NLSY) to test hypotheses relevant to the discriminative validity of a trichotomous family history of problem drinking index. Early onset substance use, adolescent antisocial behaviors and lifetime alcohol and illicit drug use were used as criterion variables. METHOD: Prospective, longitudinal survey data from over 9,000 young adult subjects (ages 23-30 yrs) in the NLSY archive were used to evaluate several hypotheses regarding familial risk of alcoholism. RESULTS: General support for discriminant validity was indicated, as the high density familial risk group differed from the moderate (paternal or maternal problem drinking only) and low-risk groups with regard to a somewhat earlier onset of marijuana use, higher levels of antisocial behaviors in adolescence (especially substance-related offenses and property offenses) and higher levels of lifetime marijuana and cocaine use. The high- and moderate-risk groups differed from the low-risk group with regard to alcohol use and alcohol-disordered problems (e.g., negative consequences, dependency symptoms). CONCLUSIONS: Risk associated with high familial problem-drinking density includes an earlier onset of illicit substance use, higher rates of lifetime marijuana and cocaine use and more frequent adolescent antisocial behavior. The general pattern of the findings was robust for men and women and suggests that high-risk status may reflect both a high genetic loading and a high environmental risk loading.

Adolescent↗

On the evolutionary stability of Mendelian segregation.

We present a model of a primary locus subject to viability selection and an unlinked locus that causes sex-specific modification of the segregation ratio at the primary locus. If there is a balanced polymorphism at the primary locus, a population undergoing Mendelian segregation can be invaded by modifier alleles that cause sex-specific biases in the segregation ratio. Even though this effect is particularly strong if reciprocal heterozygotes at the primary locus have distinct viabilities, as might occur with genomic imprinting, it also applies if reciprocal heterozygotes have equal viabilities. The expected outcome of the evolution of sex-specific segregation distorters is all-and-none segregation schemes in which one allele at the primary locus undergoes complete drive in spermatogenesis and the other allele undergoes complete drive in oogenesis. All-and-none segregation results in a population in which all individuals are maximally fit heterozygotes. Unlinked modifiers that alter the segregation ratio are unable to invade such a population. These results raise questions about the reasons for the ubiquity of Mendelian segregation.

Chromosome Segregation↗

Schizophrenia and bipolar affective disorder: perspectives for the development of therapeutics.

Schizophrenia and bipolar disorder remain two of the most severe and difficult to treat psychotic disorders hampered by our poor understanding of their pathologies. The development of typical antipsychotic drugs opened an avenue of investigation through the dopamine D2 receptor in schizophrenia. With the reintroduction of the atypical antipsychotic clozapine came the development of a new generation of atypical agents and hypotheses challenging the centrality of this receptor in explaining antipsychotic effects. Evaluation of these competing theories does not provide sufficient evidence to displace the importance of the dopamine D2 receptor in antipsychotic efficacy, but does raise limitations of it as an explanatory hypothesis. Further, the treatment of other symptom domains in schizophrenia remains relatively neglected and open for the development of novel therapies. Similar to schizophrenia, bipolar disorder presents a diversity of clinical states but unlike schizophrenia, its mainstay of treatment, lithium, has not had a clear receptor target impeding understanding of the disorder's pathology and treatment. This has pushed investigation into other domains emphasising a number of intracellular signalling pathways and glial-neuronal interactions. The heavy genetic loading of bipolar disorder has allowed linkage analyses to identify a number of putative regions, however, the diversity of phenotypes complicates such studies. Polymorphisms of candidate genes have yielded potential leads such as dopamine beta hydroxylase in mood disorder and the serotonin transporter for treatment response. It is anticipated that combiningthe above approaches may hold promise for the development of more effective treatments.

Antipsychotic Agents↗

Genetics, drug dependence and schizophrenia.

It has been suggested that drug dependence is a substitute for schizophrenia in young patients and that drug dependence protects them from schizophrenic breakdown. Assuming the correctness of the genetic basis for schizophrenia, it was postulated that persons known to be dependent on heroin would have a higher genetic loading for schizophrenia if the hypothesis was true. An examination of the family backgrounds of 82 drug dependent persons failed to find supporting evidence for the belief that drug dependence is a substitute for schizophrenia in young persons.

Adolescent↗

A paradoxical locomotor response in serotonin 5-HT(2C) receptor mutant mice.

Paradoxical behavioral responses to nonselective neuropsychiatric drugs are frequently encountered and poorly understood. We report that a single receptor gene mutation produces a paradoxical response to the nonspecific serotonin receptor agonist m-chlorophenylpiperazine (mCPP). Although this compound normally suppresses locomotion, it produces hyperactivity in mice bearing a targeted mutation of the 5-HT(2C) receptor gene. This effect was blocked by pretreatment with a 5-HT(1B) receptor antagonist, indicating that the behavioral consequences of mCPP-induced 5-HT(1B) receptor stimulation are unmasked in animals devoid of 5-HT(2C) receptor function. Furthermore, this paradoxical response to mCPP was reproduced in wild-type C57BL/6 mice by previous pharmacological blockade of 5-HT(2C) receptors, indicating that the mutant phenotype does not result from perturbations of brain development. These effects of 5-HT1B and 5-HT(2C) receptor antagonists likely reflected blockade of pharmacological actions of mCPP, because these compounds did not alter locomotor activity levels when administered alone. Thus, mCPP interacts with distinct 5-HT receptor targets that produce opposing effects on locomotor activity levels. A paradoxical behavioral response is produced by the genetic inactivation of the target that produces the prevailing effect of the drug in the wild-type animal. This genetically based paradoxical drug effect provides a model for considering the effects of genetic load on neurobehavioral responses to drugs.

Animals↗

[Identification of mutations in the arylsulfatase B gene in Russian mucopolysaccharidosis type VI patients].

Molecular genetic analysis of the gene for arylsulfatase B (ASB) was conducted in ten Russian patients with type VI mucopolysaccharidosis (MPS VI) of different severity. Eight exons from the translated region of the ASB gene of each patient were amplified and sequenced using the nonradioactive method. Fourteen mutant alleles were identified in the sample studied by means of DNA analysis; 13 of them had not been described before. All patients except for one, who was an offspring of a consanguineous marriage, were genetic compounds with respect to the mutations found. Polymorphic sites A/G 1072 and A/G 1126, which were earlier revealed in exon 5 of the ASB gene, were found in five out of ten patients studied. The spectrum of mutant alleles of the ASB gene was highly specific and agreed with the characteristics of the population genetic load.

Base Sequence↗

[A-56-year-old woman with parkinsonism, whose mother had Parkinson's disease].

We report a 56-year-old woman with progressive gait disturbance. Her mother had Parkinson's disease with onset at age 70. She died at age 74 and the post-mortem examination confirmed the diagnosis of Lewy body positive Parkinson's disease. The patient was well until the age of 50(1995) when she noted an onset of resting tremor and difficulty of gait. She also developed delusional ideation and was admitted to a psychiatric service of another hospital, where a major tranquilizer was given. The delusion disappeared but she developed marked rigidity. The major tranquilizer was discontinued and an anticholinergic and amantadine HCl were given. She showed marked improvement to Hoehn and Yahr stage II and was discharged. In 1995, when she was 52 years of the age, she developed delusion again and a major tranquilizer was given. She developed marked parkinsonism again and became Hoehn and Yahr stage V. The major tranquilizer was discontinued and she was treated with levodopa/carbidopa, trihexyphenidyl, bromocriptine, and dops. She improved remarkably to stage II. She was admitted to our service on October 8, 1996 for drug adjustment. She was alert and not demented. She was anxious but delusion or hallucination was noted. Higher cerebral functions were intact. Cranial nerve functions were also intact except for masked face and small voice. Her posture was stooped and steps were small. She showed retropulsion and moderate bradykinesia. Resting tremor was noted in her left hand. Rigidity was noted in both legs. No cerebellar ataxia or weakness was noted. Deep tendon reflexes were within normal range and sensation was intact. Her cranial MRI revealed some atrophic changes in the putamen, in which a T 2-high signal linear lesion was seen along the lateral border of the putamen bilaterally. In addition, posterior part of the putamen showed T 2-low signal intensity change. She was treated with 1.6 mg of talipexole, 6 mg of trihexyphenidyl, and 100 mg of L-dops. She was in stage III of Hoehn and Yahr. She developed neurogenic bladder with a large amount of residual urine for which she required catheterization. She was transferred to another hospital. Despite drug adjustment, she lost response to levodopa and her parkinsonism deteriorated gradually. She also developed syncope orthostatic hypotension. In April of 1998, she developed intracerebral hemorrhage and was admitted again on April 19, 1998. She was unable to stand and showed marked akinesia and rigidity. She was in stage V of Hoehn and Yahr. Her cranial CT scan revealed bilateral high-density lesions in the posterior parietal lobes. She developed dysphagia for which she required gastrostomy. She was transferred to another hospital but her clinical condition deteriorated further. On December 22, 1999, she developed fever and dyspnea and was admitted to our service again. She developed cardial arrest at the emergency room from hypoxia. She was resuscitated; however, she was comatose with loss of brain stem reflexes. Later on she developed generalized myoclonus. She developed cardiac arrest and pronounced dead on December 28, 1999. The patient was discussed in a neurological CPC. The chief discussant arrived at the conclusion that the patient had striatonigral degeneration because of poor response to levodopa in the later course, autonomic failures, and MRI changes. Some other participants thought that the patient had a form of familial Parkinson's disease. Opinions were divided into these two possibilities. Post-mortem examination revealed that the substantia nigra showed intense neuronal loss and gliosis, however, no Lewy bodies were seen. In addition, intracytoplasmic inclusions were seen in oligodendrocytes. The putamen was markedly atrophic in its posterior part with marked gliosis and neuronal loss. The ventromedial part of the pontine nucleus also showed neuronal loss and intracytoplasmic glial inclusions. Pathologic diagnosis was multiple system atrophy. In the parietal lobe, an arteriovenous malformation with bleeding was noted. This is very unique case. Although her mother had Lewy body-positive Parkinson's disease, the patient had Lewy body-negative multiple system atrophy with a-synuclein-positive glial inclusions. Whether this is just a coincidental occurrence or the presence of a genetic load for Parkinson's disease might triggered her multiple system atrophy is an interesting question to be answered in future.

Brain↗