Copyright (c) 2009 All rights reserved. http://works.bepress.com/christina_sobin Recent documents in Christina Sobin, Ph.D. en-us Sat, 10 Oct 2009 13:52:59 PDT 3600 http://works.bepress.com/christina_sobin/15 http://works.bepress.com/christina_sobin/15 Tue, 25 Aug 2009 15:26:20 PDT Low-level lead exposure during early childhood has long been associated with altered neurocognitive development and diminished cognitive functions. Over nine thousand U.S. industrial facilities annually emit significant amounts of lead, creating exposure risk particularly for minority children. The mechanisms by which low-level lead exerts neurotoxic effects are poorly understood. Once absorbed, the only intervention is source removal, thus primary prevention is key. Genetic biomarkers could provide an efficient means of identifying children at greatest risk. Common functional variants of genes that alter lead's neurotoxic potential have been identified and include delta-aminolevulinic acid dehydratase (ALAD2) and peptide transporter 2 (PEPT2*2). These polymorphisms have not been examined previously in Hispanic minority samples, or with regard to lowest level lead exposure. In 116 children of Mexican-American/Hispanic descent residing in zip codes previously designated as "high risk" for lead exposure (mean age = 8.1, SD = 1.9), blood lead level was measured at three time points over a three month period and averaged. DNA extraction was completed using buccal swab samples. The frequencies of the ALAD2 and PEPT2*2 polymorphisms observed in this sample closely approximated those previously reported for Anglo, European and Asian samples. As compared to children heterozygous for the PEPT2*2 polymorphism, and without the PEPT2*2 polymorphism, the geometric mean blood lead level of children homozygous for the PEPT2*2 polymorphism was significantly higher. In contrast to past studies, mean blood lead level of children heterozygous and homozygous for the ALAD2 polymorphism in this sample did not differ from that of children without the ALAD2 polymorphism. Higher blood lead burden in children with the PEPT2*2 mutation may suggest that this common genetic variant is a biomarker of increased vulnerability to the neurotoxic effects of lowest level lead exposure. Christina Sobin Genes and Neurocognition http://works.bepress.com/christina_sobin/14 http://works.bepress.com/christina_sobin/14 Fri, 18 Apr 2008 08:50:22 PDT High rates of psychiatric impairment in adults with 22q11DS suggest that behavioral trajectories of children with 22q11DS may provide critical etiologic insights. However past findings based on DSM disorders are extremely variable, moreover gender has not yet been examined. Dimensional CBCL ratings from 82 children, including 51 with the 22q11DS and 31 control siblings were analyzed. Strikingly consistent with rates of psychiatric impairment among affected adults, 25% percent of children with 22q11DS had high CBCL scores for Total Impairment, and 20% had high CBCL Internalizing Scale scores. Males accounted for 90% of high Internalizing scores and 67% of high Total Impairment scores. Attention and Social Problems were ubiquitous; more affected males than females (23% vs. 4%) scored high on Thought Problems. With regard to CBCL/DSM overlap, 20% of affected males as compared with 0 affected females had one or more high CBCL ratings in the absence of a DSM diagnosis. Behaviors of children with 22q11DS are characterized by marked gender differences when rated dimensionally, with significantly more males experiencing Internalizing and Thought Problems. Categorical diagnoses do not reflect behavioral gender differences in children with 22q11DS, and may miss significant behavior problems in 20% of affected males. Christina Sobin Genes and Neurocognition http://works.bepress.com/christina_sobin/13 http://works.bepress.com/christina_sobin/13 Mon, 25 Feb 2008 07:24:49 PST Christina Sobin http://works.bepress.com/christina_sobin/12 http://works.bepress.com/christina_sobin/12 Wed, 10 Oct 2007 16:36:58 PDT Christina Sobin Non-Psychiatric Precursors http://works.bepress.com/christina_sobin/10 http://works.bepress.com/christina_sobin/10 Wed, 10 Oct 2007 16:36:57 PDT Objective: The 22q11 deletion syndromeis associated with a range of possible physicalanomalies, probable ongoing learningdisabilities, and a specific constellation ofneuropsychological deficits, including impairmentsin selective and executive visualattention, working memory, and sensorimotorfunctioning. It has been estimatedthat 25% of the children with 22q11 deletionsyndrome go on to develop schizophreniain late adolescence or adulthood.This is of urgent concern. Specification ofearly brain network vulnerabilities mayprovide a basis for early intervention whileindicating critical links between genes andsevere psychiatric illness. Neuropsychologicalstudies of children with 22q11 deletionsyndrome have implicated an array ofpotentially aberrant brain pathways. Thisstudy was conducted to determine whetherpreattentive processing ("sensorimotor gating")deficits are present in this population.Method: The authors administered a testof prepulse inhibition to 25 children with22q11 deletion syndrome and their 23sibling comparison subjects, ages 6-13. Itwas predicted that the children with22q11 deletion syndrome would havelower prepulse inhibition than the comparisonsubjects.Results: Prepulse inhibition in the childrenwith 22q11 deletion syndrome(26.06%) was significantly less than that ofthe sibling comparison subjects (46.41%).Secondary analyses suggested that thisdecrement did not reflect developmentaldelay, and lower prepulse inhibition wasassociated with particular subsyndromalsymptoms in some children.Conclusions: Sensorimotor gating islower in children with 22q11 deletionsyndrome. These findings may indicatespecific brain circuits that are anomalousin 22q11 deletion syndrome. Christina Sobin Genes and Neurocognition http://works.bepress.com/christina_sobin/11 http://works.bepress.com/christina_sobin/11 Wed, 10 Oct 2007 16:36:57 PDT Christina Sobin Neuromotor Symptoms in Mental Illness http://works.bepress.com/christina_sobin/9 http://works.bepress.com/christina_sobin/9 Wed, 10 Oct 2007 16:36:56 PDT The 22q11 chromosomal deletion syndrome (22q11DS) is associated with a heterogeneous physical phenotype, neurocognitive deficits, and increased risk of later psychiatric illness. Sporadic clinical reports suggested motor differences, but quantitative studies of movement in children with 22q11DS are rare. If present in a majority of affected schoolage children, characterization of neuromotor deficits may prove to be critical for intervention, neurocognitive test interpretation, and understanding etiology. We administered the Movement Assessment Battery for Children to 72 children ages 4.3 to 16.1, including 49 children confirmed positive for the 22q11 deletion and 23 control siblings. We predicted a higher frequency of global and domain impairment in manual dexterity, eye-hand coordination, and balance among affected children. Ninety-four percent of affected children had marked neuromotor deficits, and group scores differed broadly for both global and subarea measures. Secondary analyses showed no impairment differences between younger and older children with 22q11DS, and longitudinal trajectories for 12 affected children suggested stability of deficits over 3-year intervals. Neuromotor deficits in children with 22q11DS occur early in development, continue throughout the school-age years, should be considered in the interpretation of motor-based achievement and IQ tests, and require targeted and ongoing remediation throughout childhood and adolescence. Further studies examining the specificity of motor impairment to 22q11DS are needed. Christina Sobin Genes and Neurocognition http://works.bepress.com/christina_sobin/8 http://works.bepress.com/christina_sobin/8 Wed, 10 Oct 2007 16:36:56 PDT Christina Sobin http://works.bepress.com/christina_sobin/6 http://works.bepress.com/christina_sobin/6 Wed, 10 Oct 2007 16:36:55 PDT Previous reports of cognitive functioning in children with the 22q11 Deletion Syndrome have reported marked variability in IQ and achievement subtest scores. Studies have begun to explore neuropsychological function in 22q11 DS however results are inconsistent and the profile incomplete. We assessed 40 children ages 5-12 with 22q11 DS. Consistent with past results, visual-spatial memory was significantly lower than verbal memory. Differentially lowered scores were found only in visual attention, working memory and motor function. Contrary with some past results quantitative, verbal ability, and visual spatial memory scores were within 1 SD from the standardization sample mean. Motor behavior, not typically discussed with regard to 22q11 DS school-age children, may be critical to incorporate in neurocognitive studies of children with 22q11 DS. Implications of these findings are considered with regard to past results. Christina Sobin Genes and Neurocognition http://works.bepress.com/christina_sobin/7 http://works.bepress.com/christina_sobin/7 Wed, 10 Oct 2007 16:36:55 PDT Christina Sobin Non-Psychiatric Precursors