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Biomedical subjects

S Dimiceli

Publications and source records attributed to S Dimiceli.

10 recordsLinked to original sources

Birth order effects on nonverbal IQ scores in autism multiplex families.

Lord (1992) published a brief report showing a trend for decreasing nonverbal IQ scores with increasing birth order in a sample of 16 autism multiplex families, and urged replication in a larger sample. In this report, analyses of nonverbal IQ scores for a sample of 144 autism multiplex families indicated that nonverbal IQ scores were significantly lower in secondborn compared with firstborn siblings with autism. This birth order effect was independent of gender as well as the age differences within sib pairs. No such birth order effects were found for social or communicative deficits as measured by the Autism Diagnostic Interview-Revised (ADI-R), but there was a modest tendency for increased scores for ritualistic behaviors for the firstborn sibs. Further, there were no gender differences on nonverbal IQ scores in this sample. Results are discussed in terms of implications for genetic studies of autism.

Autistic Disorder↗

Absence of linkage and linkage disequilibrium to chromosome 15q11-q13 markers in 139 multiplex families with autism.

Chromosomal region 15q11-q13 has been implicated to harbor a susceptibility gene or genes underlying autism. Evidence has been derived from the existence of cytogenetic anomalies in this region associated with autism, and the report of linkage in a modest collection of multiplex families. Most recently, linkage disequilibrium with the marker GABRB3-155CA2 in the candidate locus GABRB3, located in this region, has been reported. We searched for linkage using eight microsatellite markers located in this region of chromosome 15 in 147 affected sib-pairs from 139 multiplex autism families. We also tested for linkage disequilibrium in the same set of families with the same markers. We found no evidence for excess allele sharing (linkage) for the markers in this region. Also, we found no evidence of linkage disequilibrium, including for the locus GABRB3-155CA2. Thus, it appears that the role of this region of chromosome 15 is minor, at best, in the majority of individuals with autism.

Adolescent↗

Exclusion of linkage to the HLA region in ninety multiplex sibships with autism.

Several studies have suggested a role for the histocompatibility complex of loci (HLA) in the genetic susceptibility to autism. We have tested this hypothesis by linkage analysis using genetic marker loci in the HLA region on chromosome 6p in multiplex families with autism. We have examined sharing of alleles identical by descent in 97 affected sib pairs from 90 families. Results demonstrate no deviation from the null expectation of 50% sharing of alleles in this region; in fact, for most marker loci, the observed sharing was less than 50%. Thus, it is unlikely that loci in this region contribute to the genetic etiology of autism to any significant extent in our families.

Adolescent↗

A genomic screen of autism: evidence for a multilocus etiology.

We have conducted a genome screen of autism, by linkage analysis in an initial set of 90 multiplex sibships, with parents, containing 97 independent affected sib pairs (ASPs), with follow-up in 49 additional multiplex sibships, containing 50 ASPs. In total, 519 markers were genotyped, including 362 for the initial screen, and an additional 157 were genotyped in the follow-up. As a control, we also included in the analysis unaffected sibs, which provided 51 discordant sib pairs (DSPs) for the initial screen and 29 for the follow-up. In the initial phase of the work, we observed increased identity by descent (IBD) in the ASPs (sharing of 51.6%) compared with the DSPs (sharing of 50.8%). The excess sharing in the ASPs could not be attributed to the effect of a small number of loci but, rather, was due to the modest increase in the entire distribution of IBD. These results are most compatible with a model specifying a large number of loci (perhaps >/=15) and are less compatible with models specifying </=10 loci. The largest LOD score obtained in the initial scan was for a marker on chromosome 1p; this region also showed positive sharing in the replication family set, giving a maximum multipoint LOD score of 2.15 for both sets combined. Thus, there may exist a gene of moderate effect in this region. We had only modestly positive or negative linkage evidence in candidate regions identified in other studies. Our results suggest that positional cloning of susceptibility loci by linkage analysis may be a formidable task and that other approaches may be necessary.

Adolescent↗

Prediction of the development of low birth weight preterm infants by a new neonatal medical index.

A new neonatal medical index (NMI) was used to predict the mental and motor development of low birth weight, preterm infants up to 3-years-old. The NMI is a summary score of only a few clinically salient items that are readily available on brief chart review. The sample consisted of 512 of 608 infants randomly assigned to the control group of the eight-site Infant Health and Development Program and on whom the complete set of developmental outcome measures was available. The developmental tests administered were the Bayley Scales at 12 and 24 months and the Stanford-Binet at 3 years. The findings indicated the NMI was predictive of later cognitive and motor development, and in infants born weighing less than 1500 g, the effects of neonatal medical complications continued to adversely influence these children's development to at least 3 years of age. In the heavier babies the developmental effects of sociodemographic factors predominated by 24 months and beyond.

Child Development↗

Establishing the reliability and developmental validity of a neurobehavioral assessment for preterm infants: a methodological process.

The Neurobehavioral Assessment of the Preterm Infant was developed in 3 phases: a pilot study, an exploratory study, and a validation study. In the exploratory study, clusters characterized by conceptual cohesion and face validity were systematically subjected to statistical analyses to determine whether they also had high test-retest reliability and developmental validity. In the validation study, a shortened version of the test was used with an independent cohort of 290 preterm infants. A step-by-step methodological process was used to test whether the results from the exploratory study would generalize over cohorts, different versions of the test, different hospitals, and changes in examiners. This process yielded 7 highly stable, developmentally valid, and representative preterm neurobehavioral functions that generalized over the exploratory and the validation studies. These were: motor development and vigor, scarf sign, popliteal angle, alertness and orientation, percent asleep ratings, irritability, and vigor of crying.

Apgar Score↗

Stable individual differences in developmentally changing preterm infants: a replicated study.

In a longitudinal study with the Neurobehavioral Maturity Assessment (NB-MAP), developmental changes and stability of individual differences were assessed in 2 independent samples of preterm infants ranging from 32 weeks conceptional age to term. Individual stability of response was assessed using regression analysis with repeated measures on subjects. The large majority of the functions tested showed highly significant developmental gains with age and highly significant individual stability of performance across age. These findings replicated well across the 2 cohorts. The results are discussed in the light of the neurobiological stage of development of preterm infants during the last 8 weeks prior to term.

Humans↗

A methodological approach to developing an assessment procedure for testing the neurobehavioral maturity of preterm infants.

Using data from 179 preterm infants, a neurobehavioral maturity assessment was developed by using a process in which clusters characterized by conceptual coherence and face validity were systematically subjected to statistical analyses designed to test whether they also had high test-retest reliability, statistical cohesion, and developmental validity. The psychometric soundness of the test items was made a precondition for their inclusion into the assessment procedure. Also tested were cluster redundancy, as well as the impact of gestational and conceptional age, and of postbirth influences on the functions tested. 8 dimensions of neurobehavioral functioning were found to be stable with a test-retest reliability of at least .6 or higher on 2 consecutive days, nonredundant and developmentally valid. They were: Active Tone/Motor Vigor, Alertness and Orientation, Excitation Proneness, Inhibition Proneness, Scarf Sign, Popliteal Angle, Maturity of Vestibular Response, and Vigor of Crying.

Arousal↗

Comparison of lesbian and heterosexual women's response to newly diagnosed breast cancer.

In a study comparing lesbian and heterosexual women's response to newly diagnosed breast cancer, we compared data from 29 lesbians with 246 heterosexual women with breast cancer. Our hypotheses were that lesbian breast cancer patients would report higher scores of mood disturbance; suffer fewer problems with body image and sexual activity; show more expressiveness and cohesiveness and less conflict with their partners; would find social support from their partners and friends; and would have a poorer perception of the medical care system than heterosexual women. Our predictions regarding sexual orientation differences were supported for results regarding body image, social support, and medical care. There were no differences in mood, sexual activity or relational issues. Not predicted were differences in coping, indicating areas of emotional strength and vulnerability among the lesbian sample.

Acute Disease↗