Objective: Children and adolescents with Down Syndrome have demonstrated lower levels of participation in Physical Activity than their typically developing peers. Persons diagnosed with Down Syndrome are at a higher prevalence rate for many health conditions, specifically obesity. Physical Activity has proven to be very beneficial in creating and maintaining good friendships, self-esteem and is essential to maintain a healthy life. Yet children and adolescents face many challenges to participate in these environments. Therefore, this study is focusing on the environmental barriers to participation in Physical Activity. Method: A literature search on four databases namely ERIC, CINAHL, PsycINFO and PubMed alongside with a hand search on the reference lists of the relevant articles were conducted for suitable literature to be retrieved. The inclusion criteria included were studies published in English, after the year 2000 which focus on barriers to Physical Activity among children and adolescents aged 0-18. Results: Six articles from six different countries were utilized to meet the aim of the review. The identified environmental barriers were lack of transport, negative attitudes, parental responsibilities, lack of specifically designed activities and lack of opportunities. Although some results contrasted with each other, it was identified that children and adolescents with Down Syndrome have many difficulties in the environment that obstructs them from partaking in activities. Conclusions: The hindrances to Physical Activity are different depending of various cultures the child lives. It is important to identify these barriers and find ways to eradicate them by means of supportive factors. Although children and adolescents with Down Syndrome are more prone to various health conditions that possess numerous challenges, more attention should be given in consideration for future research and interventions.

<p>Studien bygger på en sammanställning av tidigare insamlad och ej bearbetad data. Syftet med studien var att jämföra om det fanns några skillnader kring känslor hos mödrar och fäder till barn med Downs syndrom (DS). 80 mödrar respektive 79 fäder deltog i studien. De fick svara på en enkät gällande känslor under en tidsperiod på tre månader tillbaka. Barnens medelålder var 4,7 år då föräldrarna besvarade enkäten. Enkäten som användes i föreliggande studie bestod av 21 stycken känslouttryck som skulle skattas på en Visuell Analog Skala (VAS) från 0-10. Resultatet visade att mödrar och fäder till barn med DS skattade ”glad” högst och ”förkrossad” lägst. ”Glad”, ”arg” och ”ledsen” var signifikant högre hos mödrarna jämfört med hos fäderna. Fäderna skattade ”bitter/dyster” signifikant högre än mödrarna. För övrigt fanns inga signifikanta skillnader mellan föräldrarna. Totalt skattade mödrar och fäder de positiva känslouttrycken högre än de negativa. Resultatet i studien tyder på att mödrar och fäder till barn med DS inte är i behov av könsanpassad utan istället individanpassad stöttning och vägledning.</p> / <p> This study is based on a compilation of previously collected and unprocessed data. The purpose of the study was to compare whether there were any differences between the feelings of mothers and fathers of children with Down syndrome (DS). 80 mothers and 79 fathers participated in the study. The children´s average age was 4,7 years when the parents answered the questionnaire. They were responding to a questionnaire concerning feelings over a period of three months. The survey that was used in the study consisted of 21 emotional expressions that would be estimated on a Visual Analog Scale (VAS) of 0-10. The results showed that both mothers and fathers of children with DS estimated "happy" highest and "devastated" lowest. "Happy", "angry" and "sorry" was significantly higher in mothers compared to fathers. Fathers estimated "bitter / gloomy" significantly higher than the mothers. Moreover, there were no significant differences between the parents. Both mothers and fathers estimated the positive emotional expressions higher than the negative. The results of the study interpret that mothers and fathers of children with DS are not in need of gender-adapted but personalized support and guidance.</p>

<p>The birth of a child marks a new era for the parents. It is the beginning of something that will never end, because they will always be the child´s parents. This study investigates what happens when an infant is born whit Downs syndrome (Ds), and thus does not resemble the child the parents had expected. The purpose of this literature study was to describe the information and the support that the parents of a newborn child with Ds think that they need. The literature search was made in the database of Medline (via Pub Med), Academic Search Elite and manual search. Twenty one scientific articles were used in the results. The analysis resulted in four describing questions about parents’ experience of having a child with Down syndrome, the support that they thought that they needed, the information they got and the timing of it and also parents’ connection to the child. The result showed that many parents experienced it hard to share their parenthood with health professionals. Sometimes the parents did not know how to act and observe around the child. Parents describe that support fails to materialise from family and friends. The most important time of connection to the child is the first five weeks after birth. The sooner that the parents got the information the better satisfied and calm the parents became, and when the diagnos is given it should, if possible, be with the mother and the father together when they are told about their child’s condition. The infant should be present when parents are informed that the child has Ds. The infant should also be referred to by name, so that his or her worth as a human being can be stressed. It is important for the parents to be offered some time to ask question about the diagnosis. Health care professionals should keep their personal opinions to themselves and the parent’s should be provided with up-to-date information about Ds. After the initial diagnosis or suspicion is shared with the parents, they should be offered a private hospital room and be introduced to a support group, and to be treated individually and not like everybody else.</p> / <p>När ett barn föds påbörjas en ny tideräkning för föräldrarna. Nu börjar något som inte kommer att ta slut, för de ska alltid vara barnets föräldrar. I denna studie undersöks vad som händer då barnet har fått diagnosen Downs syndrom (Ds) och inte liknar det barn föräldrarna väntat sig. Syftet med denna litteraturstudie är att beskriva den information och det stöd föräldrar till nyfödda barn med Downs syndrom anser sig behöva. Litteratursökningen har gjorts i databaserna Medline (via Pub Med), Academic Search Elite och manuell sökning. Tjugoen vetenskapliga artiklar valdes ut till resultatdelen. Analysen resulterade i fyra beskrivande frågor om föräldrars upplevelse till att få ett barn med Ds, vilket stöd de ansåg sig behöva, den information de fick och när de behövde den tidsmässigt samt föräldrars anknytning till barnet. Resultatet visade att många föräldrar upplevde det som svårt att dela sitt föräldraskap med en rad professionellt kunnig vårdpersonal. Ibland var det svårt för föräldrarna att veta hur de skulle betrakta barnet. Därför är det viktigt att förmedla orsakerna om Ds för föräldrarna så att dem inte klandrar sig själva och så att modern och fadern tillsammans kan ansvara för sitt barn. Föräldrarna beskriver att stödet och gratulationerna från släkt och vänner uteblir. Den viktigaste tiden för anknytningen till barnet är de första fem veckorna efter födseln. Desto tidigare informationen gavs till föräldrarna desto mera nöjda och lugna blev föräldrarna, och när beskedet skall ges ska, om möjligt båda föräldrarna närvara så snart diagnosen är ställd. Barnet bör om det går, vara med under tiden informationen och diagnosen ges. Det nyfödda barnet ska referera till dess namn, så att hans eller hennes värde som en människa kan tillkännages. Föräldrarna vill kunna ställa frågor om diagnosen, personalen ska inte delge sina egna åsikter och man ska kunna bli erbjuden färskt material om Ds. Dessutom bör de få tillgång till stödgrupper och bli erbjuden ett privat rum efter beskedet, allt för att få känna sig individuellt behandlad och inte som en i mängden.</p>

The birth of a child marks a new era for the parents. It is the beginning of something that will never end, because they will always be the child´s parents. This study investigates what happens when an infant is born whit Downs syndrome (Ds), and thus does not resemble the child the parents had expected. The purpose of this literature study was to describe the information and the support that the parents of a newborn child with Ds think that they need. The literature search was made in the database of Medline (via Pub Med), Academic Search Elite and manual search. Twenty one scientific articles were used in the results. The analysis resulted in four describing questions about parents’ experience of having a child with Down syndrome, the support that they thought that they needed, the information they got and the timing of it and also parents’ connection to the child. The result showed that many parents experienced it hard to share their parenthood with health professionals. Sometimes the parents did not know how to act and observe around the child. Parents describe that support fails to materialise from family and friends. The most important time of connection to the child is the first five weeks after birth. The sooner that the parents got the information the better satisfied and calm the parents became, and when the diagnos is given it should, if possible, be with the mother and the father together when they are told about their child’s condition. The infant should be present when parents are informed that the child has Ds. The infant should also be referred to by name, so that his or her worth as a human being can be stressed. It is important for the parents to be offered some time to ask question about the diagnosis. Health care professionals should keep their personal opinions to themselves and the parent’s should be provided with up-to-date information about Ds. After the initial diagnosis or suspicion is shared with the parents, they should be offered a private hospital room and be introduced to a support group, and to be treated individually and not like everybody else. / När ett barn föds påbörjas en ny tideräkning för föräldrarna. Nu börjar något som inte kommer att ta slut, för de ska alltid vara barnets föräldrar. I denna studie undersöks vad som händer då barnet har fått diagnosen Downs syndrom (Ds) och inte liknar det barn föräldrarna väntat sig. Syftet med denna litteraturstudie är att beskriva den information och det stöd föräldrar till nyfödda barn med Downs syndrom anser sig behöva. Litteratursökningen har gjorts i databaserna Medline (via Pub Med), Academic Search Elite och manuell sökning. Tjugoen vetenskapliga artiklar valdes ut till resultatdelen. Analysen resulterade i fyra beskrivande frågor om föräldrars upplevelse till att få ett barn med Ds, vilket stöd de ansåg sig behöva, den information de fick och när de behövde den tidsmässigt samt föräldrars anknytning till barnet. Resultatet visade att många föräldrar upplevde det som svårt att dela sitt föräldraskap med en rad professionellt kunnig vårdpersonal. Ibland var det svårt för föräldrarna att veta hur de skulle betrakta barnet. Därför är det viktigt att förmedla orsakerna om Ds för föräldrarna så att dem inte klandrar sig själva och så att modern och fadern tillsammans kan ansvara för sitt barn. Föräldrarna beskriver att stödet och gratulationerna från släkt och vänner uteblir. Den viktigaste tiden för anknytningen till barnet är de första fem veckorna efter födseln. Desto tidigare informationen gavs till föräldrarna desto mera nöjda och lugna blev föräldrarna, och när beskedet skall ges ska, om möjligt båda föräldrarna närvara så snart diagnosen är ställd. Barnet bör om det går, vara med under tiden informationen och diagnosen ges. Det nyfödda barnet ska referera till dess namn, så att hans eller hennes värde som en människa kan tillkännages. Föräldrarna vill kunna ställa frågor om diagnosen, personalen ska inte delge sina egna åsikter och man ska kunna bli erbjuden färskt material om Ds. Dessutom bör de få tillgång till stödgrupper och bli erbjuden ett privat rum efter beskedet, allt för att få känna sig individuellt behandlad och inte som en i mängden.

Målet med den här studien var att beskriva upplevelsen av att få ett barn med Down Syndrom. Vi valde att använda oss av självbiografier då det inte har gjorts så många kvalitativa studier inom detta ämne i Sverige. Vår kvalitativa innehållsanalys följer modellen: Att analysera berättelser (Friberg, 2006). Resultatet blev åtta teman: Personalens påverkan i samband med förlossningen, ovisshet och oro vid den första misstanken, upplevelser i samband med beskedet, upplevelse av skuld, flykt och misslyckande, upplevelse av sorg och smärta, omgivningens reaktioner och påverkan, fördomar och oro inför framtiden och så blev vardagen. Resultatet visar att nyblivna föräldrar till barn med Downs Syndrom har ett stort behov av stöd från omvårdnadspersonalen. Föräldrarna beskriver en väldigt påfrestande situation som kräver uppmuntran från omgivningen. De beskriver också svårigheter med att hantera de egna fördomarna. Omvårdnadspersonal bör känna till hur viktigt det är med adekvat information om Downs Syndrom. Föräldrarna behöver detta för att bearbeta sina förutfattade meningar men också för att delge denna information till släktingar och vänner. Genom en god förståelse för hur föräldrarna upplever sin situation kan omvårdnadspersonal bättre tillgodose föräldrarnas behov. / The aim of the study was to describe the experience of becoming a parent to a child with Down Syndrome. We chose to analyse autobiographies since there are few qualitative studies made in Sweden in this area. To do our qualitative content analysis we used Fribergs (2006) method to analyse narratives, which resulted in eight themes: The nursing staff's impact during and after childbirth, uncertainty and dread at the first suspicion, experiences in connection with the reply, to experience feelings of blame and escape and failure, to experience sorrow and pain, reactions and impact from the environment, prejudices and dread for the future and everyday existence. The results indicates that becoming a parent to a child with Down Syndrome means a great need of support from the nursing staff. The parents describe a very stressfull situation that requires encouraging from the environment. They also describe difficulties in handling their own prejudices. Nursing staff should know how important it is with adequate information about Down Syndrome, the parents need it to control their prejudices and also inform their relatives and closest friends. By understanding this situation nursing staff can meet the parents needs and requirements.

Studien bygger på en sammanställning av tidigare insamlad och ej bearbetad data. Syftet med studien var att jämföra om det fanns några skillnader kring känslor hos mödrar och fäder till barn med Downs syndrom (DS). 80 mödrar respektive 79 fäder deltog i studien. De fick svara på en enkät gällande känslor under en tidsperiod på tre månader tillbaka. Barnens medelålder var 4,7 år då föräldrarna besvarade enkäten. Enkäten som användes i föreliggande studie bestod av 21 stycken känslouttryck som skulle skattas på en Visuell Analog Skala (VAS) från 0-10. Resultatet visade att mödrar och fäder till barn med DS skattade ”glad” högst och ”förkrossad” lägst. ”Glad”, ”arg” och ”ledsen” var signifikant högre hos mödrarna jämfört med hos fäderna. Fäderna skattade ”bitter/dyster” signifikant högre än mödrarna. För övrigt fanns inga signifikanta skillnader mellan föräldrarna. Totalt skattade mödrar och fäder de positiva känslouttrycken högre än de negativa. Resultatet i studien tyder på att mödrar och fäder till barn med DS inte är i behov av könsanpassad utan istället individanpassad stöttning och vägledning. / This study is based on a compilation of previously collected and unprocessed data. The purpose of the study was to compare whether there were any differences between the feelings of mothers and fathers of children with Down syndrome (DS). 80 mothers and 79 fathers participated in the study. The children´s average age was 4,7 years when the parents answered the questionnaire. They were responding to a questionnaire concerning feelings over a period of three months. The survey that was used in the study consisted of 21 emotional expressions that would be estimated on a Visual Analog Scale (VAS) of 0-10. The results showed that both mothers and fathers of children with DS estimated "happy" highest and "devastated" lowest. "Happy", "angry" and "sorry" was significantly higher in mothers compared to fathers. Fathers estimated "bitter / gloomy" significantly higher than the mothers. Moreover, there were no significant differences between the parents. Both mothers and fathers estimated the positive emotional expressions higher than the negative. The results of the study interpret that mothers and fathers of children with DS are not in need of gender-adapted but personalized support and guidance.

The purpose of this study was to compare the accuracy of eight anthropometric regression equations with hydrostatic weighing for predicting the percent body fat of adult males with Down Syndrome (DS). Body fat percentages were predicted for 18 adult males with DS. Skinfold, circumference, and bioelectric impedance analysis data were collected to determine how accurately the regression equations could predict the percent fat of these individuals when compared to hydrostatic weighing. Since hydrostatic weighing involves a number of complex procedures two pilot studies were conducted. Four subjects participated in the pilot studies. The first pilot was conducted to determine if a constant value of residual volume could be utilized during hydrostatic weighing, or if a measured value, determined by oxygen dilution, needed to be used. The second pilot was performed to determine if hydrostatic weighing at total lung capacity without head submersion could be substituted for the conventional method of hydrostatic weighing. Paired t-tests revealed no significant differences in either pilot study, t (3) = .274, p. < .05 and t (3) = .314, 11 < .05, respectively. Pearson product-moment correlations revealed r values of .99 for both pilot studies. Based on these results a constant residual volume value of 1.50 L and hydrostatic weighing at total lung capacity without head submersion were the procedures utilized in the main research study. A one-way repeated measures analysis of variance revealed a significant difference between the body fat data obtained from hydrostatic weighing and the regression equations, F (8, 136) = 16.05, < .05. Dunnett's post-hoc procedure revealed significant differences in five of the eight equations. Of the three equations that did not yield significantly different results, only the Kelly and Rimmer (1987), r = .89, SEE = 2.51, 12 <.05, can be recommended for use. Based on these results, it appears that a constant value of 1.50 L for residual volume and hydrostatic weighing at total lung capacity without head submersion can be utilized when predicting the percent body fat of adult males with DS. This will allow increased numbers of individuals with DS to be hydrostatically weighed. Also, the use of the Kelly and Rimmer (1987) equation will allow researchers and practitioners to utilize an easy, fast, accurate, and inexpensive method of predicting the percent body fat of adult males with DS. / Graduation date: 1992

Down syndrome (DS) is the most common genetic cause of mental challenge in individuals and is associated with many ocular disorders. One of these anomalies which is frequently present in this population is reduced accommodation and many studies have reported this. Accommodation is the ability of the crystalline lens in the eye to focus for objects at different distances. Prescribing bifocals could potentially help in correcting the resultant inaccurate focus, although this modality of treatment is not very commonly practiced. The impact of bifocals on reading and literacy skills (academic skills) as well as visual-perceptual skills in individuals with DS has not been studied previously. The aim of this study was to investigate the impact of bifocals on the educational attainment of children and young adults with DS who have reduced accommodation and monitor their performance longitudinally. This is the first time that the impact of bifocal provision on the functional performance of children and young adults with DS has been studied. Also for the first time in children with DS, frequent measures of performance have been used to control for progression with time before and after bifocal prescription. A battery of tests comprising early literacy and visual-perceptual skills was administered before and after bifocal prescription. Accommodation and printing skills were also measured periodically. It was expected that the prescription of bifocals would help to improve near visual acuity and that the improved near acuity would result in educational achievements at school. Compliance with spectacle wear and school reports were also considered. A longitudinal observational study design was utilized with each child acting as his/her own control. Fourteen children and teenagers aged 8-18 with DS were recruited and underwent a basic optometric exam including measurement of their accommodative ability and a cycloplegic refraction. Seventy nine percent required a change in their spectacle prescription and were prescribed single vision (SV) lenses. One hundred percent had reduced accommodation both before and after new SV glasses were prescribed. Distance visual acuity did not significantly improve with SV lenses (p>0.05) but near visual acuity showed a significant improvement (p-=0.015) from 0.64±0.25 logMAR to 0.54±0.20 logMAR. A high prevalence of high refractive errors, including both hyperopia and myopia, was observed t andnear visual acuity even with a habitual correctionwas reduced compared to distance VA. A full battery of reading and visual-perceptual tests was administered with SV lenses. Thereafter the participants were followed for 6 months and monthly subtests (probes) of literacy skills and printing tasks were administered. These “probes” acted as immediate indicators of the child’s performance with his/her correction and change in performance over this time period was monitored. Over the 6 months the participants showed no noteworthy progression in their literacy skills. The group of participants performed at an age-equivalent between 3-10 years. The quality of printing formation in this population has been studied for the first time and showed no significant change over time. It was observed that some aspects of visual-perceptual and early literacy skills could be measured in all the participants. Chronological age and receptive vocabulary were significantly correlated with visual motor integration and Word Identification. Eighty five percent of the participants were prescribed bifocals with additions ranging from +1.00D to +3.50D at the 6th month after the provision of SV lenses. Post-bifocal measures of visual acuity, accommodation, visual-perceptual and early literacy skills were taken 1-2 weeks, and finally 5 months, after bifocal correction. Throughout the pre- and post-bifocal period, verbal compliance with spectacle wear was assessed through school and parental reports. The mean near logMAR VA improved with bifocals (p=0.007) compared to SV lenses. Accommodative accuracy improved with bifocals (less accommodative lag) compared to SV lenses (p=0.002) but there was no change in the accommodation exerted through the distance portion of the lens compared to SV lenses (p=0.423). There was a main effect of bifocals on sight words (p=0.013), Word Identification (p=0.047), and 2 out of 3 tests of visual perception (p<0.05). It was observed that bifocals have a positive impact on the children’s visual and school performance and this was supported by reports of improved performance in school for nine out of eleven individuals who were prescribed bifocals. The children adapted to bifocals more readily than the SV glasses, wearing them for the majority of their waking time. All the sessions of early literacy and visual-perceptual skills administered throughout the duration of the study were videotaped and were then analyzed by a naïve examiner. The time taken to perform each task was calculated and compared between the main single vision and bifocal visits. There was a significant decrease in the completion times on the test battery with bifocals for Word Identification (p=0.0015) and the Dolch sight words (p=0.048). All participants who completed the monthly probes took less time to complete the Dolch sight words (p= 0.025) and the number writing task (p=0.001) with bifocals. Similar results were not observed for the visual-perceptual tests. Performance in the monthly probes was compared before and after bifocal prescription in terms of the average raw scores and time taken. The rate of improvement in performance with bifocals was calculated by plotting the test scores against time and determing the regression lines. There was an overall significant improvement in the monthly probe scores of Word Identification (p=0.050), Dolch sight words (p=0.025) and the number test (p=0.023) with bifocals. The rate of progression in scores increased with bifocals for the Word Identification (p=0.008). Evidence of improved and faster performance with bifocals on some literacy skills was seen. It was concluded that bifocals, which result in improved near focusing, help individuals with DS to maximize their educational potential. It is suggested that more children and teenagers with DS will benefit from bifocal prescription, as they were observed to improve near visual acuity and enable better focusing for near. This thesis has provided a comprehensive analysis of the some tests of literacy, visual- perceptual and early printing skills before and after a bifocal prescription in a group of children and teenagers with Down syndrome. This is the first study to longitudinally monitor the educational impact of bifocals in a population with Down syndrome. Furthermore, the quality of printing formation in this population is a previously unstudied area and was studied longitudinally prior to and after bifocal intervention. The impact of bifocals on printing skills is also discussed. Another novel approach was that all the literacy, writing and visual-perceptual tasks sessions were videotaped to calculate the time taken to complete each task pre- and post-bifocals. This thesis is an addition to the existing literature on bifocal prescription in Down syndrome populations. From the findings in this thesis, the following recommendations are made in order to improve the standard of clinical eye care in this population. Measurement of accommodation should be considered a routine test in the clinical ocular examination for young individuals with DS, now that it is known that many of them present with accommodative deficits. When accommodation is found to be reduced, prescription of bifocals is indicated and should also become the standard of care in this population.

<p>Vi har genomfört en kvalitativ intervjustudie om föräldrars erfarenheter av en vardag tillsammans med ett barn som har Downs syndrom, i synnerhet när det gäller barnets ungdomstid. Den insamlade empirin har tolkats med hjälp av Beckers (2006) teori om avvikelse, Goffmans (2001) teori om stigma samt Goffmans (2009) teori om interaktion i det vardagliga sociala livet. Föräldern ingår i ett allmänt system av normalitet, såsom övriga samhällsmedlemmar. Studiens fokus ligger på förälderns agerande utefter detta i förhållande till den situation som barnets funktionsnedsättning för med sig. Downs syndrom medför en utvecklingsstörning, vilket innebär att barnets kroppsliga och mentala utveckling inte alltid är i fas med varandra. En följd av detta är att småbarns- och ungdomstiden förlängs, vilket föräldrarna i vår studie upplever som en svårighet. Svårigheten ligger bland annat i att barnets självständighetsutveckling skiljer sig från det som i allmänhet anses vara normalt och därmed skiljer sig även förälderns roll i denna utveckling. Studien visar att föreställningar om normalitet ständigt är närvarande i föräldrarnas berättelser.</p> / <p>We have made a qualitative interview study about parents' experiences of every day life with a child who has Down syndrome, particularly with regard to the child's youth. The empirical data collected has been interpreted using Becker's (2006) theory of deviance, Goffman's (2001) theory of stigma and Goffman's (2009) theory of interaction in everyday social life. The parent are included in a general system of normality, just as any other member of society. The focus of the study is parent's acting in relation to normality and to the situation that the child's disability causes. Down syndrome results in a development disorder, which means that child's physical and mental development not always is in phase with each other. This causes an extension of the childhood and youth, which the parents in our study perceive as difficult. The difficulty lies among other things in that the child's development of independence differs from what is generally considered to be normal and that the parent's role in this development consequently also differs. The study shows that ideas of normality are constantly present in the parents' narratives. </p>

Mutations in the presenilin 1 gene account for most early-onset familial Alzheimer's disease (FAD). The presenilins and AD may also be related through a common involvement in the cell cycle. Here we report that one important aspect of the cell cycle---proper chromosome segregation---is dependent on presenilin function and therefore may be involved in AD pathogenesis. Specifically we find that FAD mutations in presenilin 1 (M146L and M146V) lead to chromosome missegregation and aneuploidy in vivo and in vitro: 1) Both metaphase chromosome analysis and in situ hybridization reveal significant aneuploidy in the lymphocytes and neurons of PS-1 transgenic mice. 2) Transiently transfected human cells expressing normal and, especially, mutant PS-1 develop aneuploidy within 48 hours, including trisomy 21, while cells transfected with dominant negative PS-1 genes lacking ?-secretase activity have no effect on chromosome segregation. 3) Analysis of mitotic spindles in the transfected cells reveals abnormal microtubule arrays and lagging chromosomes. The possible mechanisms by which cell cycle defects and chromosome missegregation induced by y-secretase may contribute to Alzheimer's disease will be discussed.