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Biomedical subjects

W G Johnson

Publications and source records attributed to W G Johnson.

At least 19 recordsLinked to original sources
PubMed1992

Parental sex effect in spina bifida: a role for genomic imprinting?

Fifty families (491 individuals in 137 sibships) with more than one living case of isolated, nonsyndromic spina bifida (SB) were analyzed genetically. There were twice as many gene-carrier females (56) as gene-carrier males (28) (P < 0.005). This was not an artifact of ascertainment bias because the sex ratio of gene-carriers was the same whether the pedigree was obtained through the proband's father or mother. Also, this effect was not observed in other disorders analyzed by the same method. Neither was the effect due to differential fertility because the number and sex of affected and unaffected children per gene-carrier parent were not different for male or female gene-carrier parents. There was no evidence that the missing male gene-carriers were lost by selective spontaneous abortion. There was no deficit of male-to-male or male-to-female transmission, excluding simple X-linked or simple mitochondrial inheritance. If genomic imprinting plays a role in the unequal female and male carrier frequencies in SB, penetrance should differ with parental sex. Penetrance was higher for offspring of female parents than of male parents, but the difference was not statistically significant. In addition, both male and female gene-carriers were frequently found in the same pedigree. Thus, the present data suggest a possible role for imprinting in SB.

Female↗
PubMed1992

The economic consequences of medical injuries. Implications for a no-fault insurance plan.

BACKGROUND: There has been little research into the actual economic consequences of medical injuries. This inhibits informed discussion of alternatives to malpractice litigation. For example, the cost of no-fault medical accident insurance has been thought to be prohibitive. METHOD: As part of a comprehensive analysis of medical injury and litigation, we interviewed a random sample of 794 individuals who had suffered medical adverse events in New York hospitals in 1984 and used their responses to calculate the cost of injuries. We then estimated the costs of a simulated no-fault insurance program that would operate as a second payer to direct insurance sources and would compensate for all financial losses attributed to medical injury. RESULTS: The estimated costs that would be paid by a simulated no-fault program were $161 million for medical care, $276 million for lost wages, and $441 million in lost household production, or a total of $878 million in 1989 dollars for the cohort of patients who were injured in 1984. CONCLUSION: Although our estimate does not include administrative costs, it nonetheless indicates that a no-fault program would not be notably costlier than the more than $1 billion New York physicians now spend annually on malpractice insurance.

Adult↗
PubMed1992

Hereditary Lewy-body parkinsonism and evidence for a genetic etiology of Parkinson's disease.

The first systematic genetic study of Parkinson's disease (PD) was carried out by Mjönes in 1949. His results indicated autosomal dominant transmission with 60% penetrance. These conclusions, however, were long discounted because oligosymptomatic and atypical relatives were counted as secondary cases without clear justification. Subsequent surveys of patient and twin studies failed to confirm evidence of familial concentration and the hypothesis of a genetic etiology was over-shadowed by interest in possible environmental neurotoxins. A growing accumulation of pedigrees of histologically confirmed Lewy-body PD over the past several years has refocused attention on genetic factors. Fluorodopa positron emission tomography (PET) studies in oligosymptomatic co-twins of probands and recent clinicopathologic studies of atypical cases have provided retrospective support for Mjönes' methodology. A survey of a personal series of PD patients showed that the majority of those for whom pedigree information was available were familial. This along with another recently reported series confirm Mjönes' data showing similar segregation ratios for siblings and parents, a low ratio of maternal:paternal transmission and a marked asymmetry in the distribution of ancestral secondary cases. These findings favor monogenic autosomal dominant inheritance and show reason to argue against a multifactorial etiology or heteroplasmy. The clinical evidence justifies searching for gene loci linked to PD. Available methods are briefly outlined. Preliminary investigations have examined possible allelic associations, e.g., with alleles of MAO-A and debrisoquine hydroxylase and linkage to the tyrosine hydroxylase gene on chromosome 11p15.5 has been excluded in one study of juvenile familial parkinsonism. Linkage mapping studies are presently underway.

Brain↗
PubMed1992

A 17th-century founder gives rise to a large north American pedigree of autosomal dominant spinocerebellar ataxia not linked to the SCA1 locus on chromosome 6.

There have been three reports since 1969 of members of a "W" family with autosomal dominant spinocerebellar ataxia (SCA), and various conclusions have been drawn about the nosology. This pedigree has been traced back over 300 years through 11 generations. Although phenotypically similar to the disorder in the Schut-Swier, Nino, and other kindreds, the disorder in the W family is not linked to the SCA1 locus on chromosome 6, as reported in those hereditary ataxia pedigrees. The W family represents the largest such North American kindred yet reported. We examined 33 family members of a distantly related branch of the W family, determined the cumulative age of onset, and projected the number of present-day gene carriers. Two cases illustrate the spectrum of symptoms among family members. Age of onset and presenting symptom, however, seem to correlate both in our patients and in those previously reported. Between 2,000 and 5,000 individuals are estimated to be at risk of developing the disorder within this pedigree alone. The pedigree reported here will be valuable in the identification and cloning of a gene for hereditary ataxia, designated "SCA2" at the Eleventh International Workshop on Human Gene Mapping.

Adult↗
PubMed1991

Genetic susceptibility to Parkinson's disease.

Genetic factors clearly cause Lewy-body Parkinson's disease (PD) in a subset of autosomal-dominant families. However, most cases of PD are sporadic. The two most likely models of four discussed for sporadic PD are the reduced penetrance model and the multifactorial model. Sporadic PD is likely to be caused by the combined effect of environmental precipitating factors and genetic susceptibility factors. Because the number of major genetic factors is likely to be small, these hypotheses can be tested and genetic factors located using linkage mapping techniques. The affected pair analysis methods are especially suited to PD. Finding the genetic susceptibility factors for PD is important because this may be the fastest way to identify the environmental precipitating factors and because it may lead to prevention of PD. Because of the usefulness of identifying genetic susceptibility factors for PD, we are carrying out linkage studies in a group of 16 large autosomal-dominant families with PD and more than 300 living affected PD pairs.

Diseases in Twins↗
PubMed1991

Genetic susceptibility to Parkinson's disease.

Genetic factors clearly cause Lewy-body Parkinson's disease (PD) in a subset of autosomal-dominant families. However, most cases of PD are sporadic. The two most likely models of four discussed for sporadic PD are the reduced penetrance model and the multifactorial model. Sporadic PD is likely to be caused by the combined effect of environmental precipitating factors and genetic susceptibility factors. Because the number of major genetic factors is likely to be small, these hypotheses can be tested and genetic factors located using linkage mapping techniques. The affected pair analysis methods are especially suited to PD. Finding the genetic susceptibility factors for PD is important because this may be the fastest way to identify the environmental precipitating factors and because it may lead to prevention of PD. Because of the usefulness of identifying genetic susceptibility factors for PD, we are carrying out linkage studies in a group of 16 large autosomal-dominant families with PD and more than 300 living affected PD pairs.

Diseases in Twins↗
PubMed1990

Prevalence of bulimia among patients in a chemical dependency treatment program.

The present study sought to determine the prevalence of bulimia in a chemically dependent population and to examine the patterns of psychopathology and eating attitudes among chemically dependent patients. Seventy-six male and 62 female consecutive admissions to an impatient treatment facility for chemical dependency were administered the BULIT. Restraint Scale, MMPI and the Marlowe-Crowne Social Desirability Scale. There was no evidence for an increased prevalence of bulimia in this sample. Five of the women (8%) achieved a cutoff score on the BULIT indicative of bulimia. The similarity between mean MMPI profiles of female patients in this sample and those previously obtained for bulimic patients was greater than the similarity between MMPI profiles for the male and female chemically dependent patients in this sample. Findings are discussed within the context of previous research.

Adult↗
PubMed1979

The development and evaluation of a behavioral weight-reduction program.

The development of a comprehensive weight-reduction program and its implementation in the clinic are described. The program consisted of explicit instructions on food monitoring, stimulus control, chaining, exercise, and self-reinforcement. The results of pilot research indicated that the program produced reliable weight loss and that its implementation in a group format was more positive. A formal experiment evaluated the effectiveness of program components in a 2 x 2 factorial design after ten weeks of treatment and at three-month and one-year follow-ups. There was significant weight loss with no main or interaction effects. At follow-up, those exposed to exercise and/or contingency management better maintained their weight loss or continued to lose. Data on the implementation of the program in a clinical setting are presented and these results compare favorably with reports from other clinics using behavior modification. It is suggested that our more positive results may be related to an emphasis on activity and life-style change in addition to changing eating behavior.

Adolescent↗
PubMed1978

Inheritance of the enzyme defect in a new hexosaminidase deficiency disease.

A new form of hexosaminidase deficiency disease is characterized clinically by mild, juvenile-onset, very slowly progressive cerebellar ataxia with macular cherry-red spots and absence of other findings. Biochemically there is striking hexosaminidase deficiency in serum, leukocytes, and fibroblasts. Hexosaminidase B appears absent, but hexosaminidase A-like and S-like activity is present on starch-gel electrophoresis. We studied hexosaminidase in leukocytes and serum from members of an affected patient's family and traced the enzyme defect through four generations. Leukocyte heat-stabile hexosaminidase in obligate and presumptive carriers was depressed both in specific activity (nanomoles per milligram of protein per hour) and as a percentage of total hexosaminidase. The carrier state was expressed in serum, but overlap with controls made this test unreliable. The similarity of these carriers to carriers of Sandhoff disease suggests that the disorders may be closely related, perhaps as allelic mutations of the hexosaminidase beta subunit. Those involve with screening for Tay-Sachs disease should be aware that persons with an increased percentage of hexosaminidase A--that is, a decreased heat-stabile fraction--may be carriers of hexosaminidase deficiency diseases.

Chemical Phenomena↗