The purpose of this study was to describe the phonetic repertoire of late 8 phonemes among adolescents and young adults with Down syndrome and then determine the relationship between age and presence of the latest developing phonemes as well as their impact on intelligibility. This study also described the stimulability profile for those late 8 phonemes that were produced in error. The Arizona Articulation and Phonology Scale was administered to individuals with Down syndrome between the ages of 12 – 21;11 to obtain a phonetic profile. Among those participants included in the study, on average, 87.5% of the late 8 phonemes were present. Seven of eight participants were stimulable for all phonemes that were misarticulated. Results did not indicate a significant correlation between either age or intelligibility and the presence of late 8 phonemes.

Individuals with Down syndrome have an increased risk formany conditions, including cardiovascular disease, cancer, infections, and osteoporosis, and endocrine, neurological, orthopedic, auditory, and ophthalmic disorders.They also are at increased risk for abuse and human rights violations and receive fewer screenings and interventions than the population without Down syndrome. In this literature review, the most common health conditions associated with Down syndrome are examined, along with the topics of sexual abuse, menstrual hygiene, contraception, and human rights. Clinical guidelines for this population are summarized in an effort to assist practicing physicians in improving their provision of health care to the adult patient with Down syndrome.

Down Syndrome is a human condition caused by an extra copy of a #21 chromosome. At least one to two percent of free (not translocated) trisomy 21 cases are mosaics, i.e., they have two or more distinct cell lines. Usually, one cell line is 47 ,XX or XY ,+21 while the other cell line is normal 46,XX or 46,XY. The purpose of the study was to establish the etiologies of the separate cell lines by determining whether the zygote was trisomic or normal. Meiotic non-disjunction in the formation of a gamete could lead to a trisomic zygote; loss of a #21 chromosome during a later mitotic division could then lead to a chromosomally normal cell line. Alternatively, a mitotic error in a normal embryo can produce a trisomy 21 cell line.

No description available.

The purpose of this study was to determine the reliability of sixteen balance tests in individuals with Down syndrome (DS). The following tests were performed on 21 participants with DS, aged 5-31 years of age; standing test on firm and soft surfaces with the eyes opened and closed, a balance subset of the Bruininks-Oseretsky test, full turn, timed-up-and-go test, forward reach, and sit-to-stand. Each participant completed all 16 assessments twice on one day and then again on a subsequent day for a total of four trials. Seven tests had reliability coefficients greater than 0.55; one-leg stand on floor (0.76), on balance beam with eyes opened (0.62) and eyes closed (0.69), heel-to-toe walk on balance beam (0.63), straight line walk on floor (0.57), and CGS on firm (0.63) and soft (0.86) surfaces with eyes opened. We recommend these seven tests for use in clinical and non clinical settings.

Identifying factors that influence physical activity (PA) among individuals with Down syndrome (DS) is essential for PA promotion. Insight can be gained from guardians and health professionals. The purpose was to compare guardians and health professional perspectives on facilitators and barriers of PA in individuals with DS. Interviews were conducted with 11 guardians (5 mothers, 4 fathers, 2 legal guardians) and 11 professionals (4 PA specialists, 3 physical therapists, 4 occupational therapists). Grounded Theory was applied to data analysis. Barriers and facilitators fit the levels of the Ecological Model of Health Behavior: (a) Intrapersonal (perceived rewards); (b) Interpersonal (interaction); (c) Community (availability of programs); (d) Organizational (school systems); (e) Policy (education). Guardians and professionals agreed on the importance of enjoyment, interaction, and programs to promote PA. Differences were found among organizational and policy levels. PA in persons with DS is influenced by interactions between individual and environmental factors.

There is a need to examine the difference in the relationship between oxygen uptake (VO2) and output from hip- and wrist-worn accelerometers in adults with Down syndrome (DS). The purpose of this study is to identify if that relationship is different between adults with and without DS. Hip- and wrist-worn accelerometer accuracy was also assessed. The sample included 16 adults with DS (10 men; age 31±15 years) and 19 adults without DS (10 men; age 24±6 years). We measured VO2 with a portable spirometer and accelerometer output (Vector Magnitude [VM]) with a hip- and a wrist-worn accelerometer. VM and group were significant predictors of VO2 (p?0.021). BMI became a significant predictor in the second model and DS was no longer significant for both accelerometer models. The Bland-Altman plots indicated nearly zero mean error for both groups. Hip-worn accelerometers showed greater accuracy, and showed less error based on 95% confidence intervals.

<p dir="ltr">Down syndrome (DS) arises from the triplication of human chromosome 21 (Hsa21), leading to a spectrum of phenotypes characterized by neurodevelopmental and cognitive abnormalities. The Ts65Dn mouse model emulates DS by harboring three copies of genes found on Hsa21 resulting in trisomy 21 (Ts21)- like traits, including disruptions in neuronal pathways, delays in sensorimotor and behavior milestones, and deficits in learning and memory tasks. There is no cure for DS and available therapies primarily address symptoms stemming from Ts21-associated phenotypes. <i>DYRK1A</i>, a gene triplicated in Ts21, has a pivotal role in pathways of neurodevelopment and has been a focus of inhibition treatment research aimed at preempting abnormal brain phenotypes. This study aimed to find a point of substantial <i>Dyrk1a </i>expression dysregulation during a period of critical neonatal neurodevelopment and employ targeted pharmacological and genetic knockdown methods to alleviate the presence or severity of characteristically abnormal brain and behavior phenotypes. The hypothesis of this study was that administering a targeted intervention prior to a point of known overexpression in trisomic pups would ameliorate molecular, sensorimotor, and neurobehavioral deficits, redirecting growth trajectories of Ts65Dn neonatal pups towards more neurotypical outcomes. To test this hypothesis, the spatiotemporal pattern of DYRK1A expression was quantified during the first three weeks of neonatal development across the hippocampus, cerebral cortex, and cerebellum of the Ts65Dn mouse model and found to fluctuate according to the genotype, age, sex, and brain region of the subject. <i>Dyrk1a </i>protein and mRNA expression levels were delineated in trisomic animals by age, exploring the correlation between expression and age, sex, genotype, and brain region. Next a constitutive <i>Dyrk1a </i>knockdown model was integrated with the Ts65Dn model to investigate the impact of gene copy number reduction on protein and mRNA expression levels during phases of known DYRK1A dysregulation. On postnatal day 6, protein expression was rescued in all three brain regions of male animals but was rescued only in the cerebellum of females. There were no significant differences in mRNA transcript levels in either sex at this age. Finally, genetic elements were introduced into the Ts65Dn model to facilitate a spatiotemporally controlled functional reduction of <i>Dyrk1a</i> and discern how the timing of gene copy number reduction affects molecular and neurobehavioral development in a trisomic system. Results from these studies suggest that only functionally reducing <i>Dyrk1a </i>gene copy number on the day of birth is not sufficient to rescue the majority of deficits and delays present in the Ts65Dn mouse model of DS. These findings significantly enhance the understanding of trisomic <i>Dyrk1a </i>expression dynamics during neonatal development and shed light on tailored therapeutic approaches to modulate intrinsic DS characteristics based on age, sex, and phenotypic considerations.</p>

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Indiana University-Purdue University Indianapolis (IUPUI) / Trisomy 21 occurs in approximately 1 out of 750 live births and causes brachycephaly, a small oral cavity, a shortened mid-face, and mental impairments in individuals with Down syndrome (DS). Craniofacial dysmorphology occurs in essentially all individuals with trisomy 21 and causes functional difficulties. Mouse models are commonly used to study the etiology of human disorders because of the conserved phenotypes between species. The Ts65Dn Down syndrome mouse model has triplicated homologues for approximately half the genes on human chromosome 21 and exhibits many phenotypes that parallel those found in individuals with DS. Specifically, newborn and adult Ts65Dn mice display similar craniofacial defects as humans with DS. Ts65Dn embryos also exhibit smaller mandibular precursors than their euploid littermates at embryonic day 9.5 (E9.5). Furthermore, Ts65Dn mice exhibit reduced birth weight which suggests a possible generalized delay in overall embryonic growth. Based on previous research at E9.5, it was hypothesized that Ts65Dn E13.5 embryos would have reduced mandibular precursors with altered gene expression. It was also hypothesized that other neural crest derived structures would be reduced in trisomic embryos. Using morphological measurements it was determined that the mandible, Meckel’s cartilage, and hyoid cartilage were significantly reduced in E13.5 trisomic embryos. The tongue was of similar size in trisomic and euploid embryos while cardiac and brain tissue volumes were not significantly different between genotypes. Analysis of total embryonic size at E9.5 and E13.5 revealed smaller trisomic embryos with developmental attenuation that was not related to maternal trisomy. A microarray analysis performed on the mandibular precursor revealed 155 differentially expressed non-trisomic genes. Sox9 was of particular interest for its role in cartilage condensation and endochondral ossification. It was hypothesized that the overexpression of Sox9 in the developing mandible would be localized to Meckel’s and hyoid cartilages. Immunohistochemistry performed on the mandibular precursor confirmed an overexpression of Sox9 in both Meckel’s and the hyoid cartilages. This research provides further insight into the development of trisomic tissues, both neural crest and non-neural crest-derived, and also the specific molecular mechanisms that negatively affect mandibular development in Ts65Dn mice and presumably individuals with Down syndrome.