Timothy Buie - Academia.edu (original) (raw)
Papers by Timothy Buie
Pediatrics, 2015
Autism spectrum disorders (ASDs) are neurodevelopmental disorders characterized by impaired socia... more Autism spectrum disorders (ASDs) are neurodevelopmental disorders characterized by impaired social communication skills and isolated areas of interest. The current prevalence of these disorders is estimated to be 1 in 68, 2 and recent estimates of the risk of recurrence in families with at least 1 child diagnosed with ASD are 10% to 19%. Advances have been made in identifying genetic variants that can account for biological vulnerability to ASD, 6,7 although recent studies examining patterns of heredity implicate environmental factors and potential gene-by-environment interactions. 8 Although the exact etiology remains unknown in most families, some researchers suggest that the pathogenesis of the disorder begins during prenatal life. 9,10 It is likely that ASD is heterogeneous in its etiology as well as in its clinical presentation. 11
Pediatrics, 2015
This article reviews current evidence for autism spectrum disorder (ASD) screening based on peer-... more This article reviews current evidence for autism spectrum disorder (ASD) screening based on peer-reviewed articles published to December 2013. Screening provides a standardized process to ensure that children are systematically monitored for early signs of ASD to promote earlier diagnosis. The current review indicates that screening in children aged 18 to 24 months can assist in early detection, consistent with current American Academy of Pediatrics' recommendations. We identify ASD-specific and broadband screening tools that have been ev-aluated in large community samples which show particular promise in terms of accurate classification and clinical utility. We also suggest strategies to help overcome challenges to implementing ASD screening in community practice, as well as priorities for future research.
Pediatrics, 2015
This article reviews current evidence for autism spectrum disorder (ASD) interventions for childr... more This article reviews current evidence for autism spectrum disorder (ASD) interventions for children aged <3 years, based on peer-reviewed articles published up to December 2013. Several groups have adapted treatments initially designed for older, preschool-aged children with ASD, integrating best practice in behavioral teaching methods into a developmental framework based on current scientific understanding of how infants and toddlers learn. The central role of parents has been emphasized, and interventions are designed to incorporate learning opportunities into everyday activities, capitalize on "teachable moments," and facilitate the generalization of skills beyond the familiar home setting. Our review identified several comprehensive and targeted treatment models with evidence of clear benefits. Although some trials were limited to 8- to 12-week outcome data, enhanced outcomes associated with some interventions were evaluated over periods as long as 2 years. Based on...
The American Journal of Gastroenterology, 2003
Disorders of the mitochondrial electron transport chain enzymes of oxidative phosphorylation (OXP... more Disorders of the mitochondrial electron transport chain enzymes of oxidative phosphorylation (OXPHOS) have neurologic, musculoskeletal, ophthalmologic, cardiac, and GI manifestations. Many adult and pediatric patients with disorders of OXPHOS have abnormalities in intestinal motility. The purpose of this study was to describe pediatric patients who initially presented with signs of GI dysmotility and were later evaluated and found to have a disorder of OXPHOS. Data were collected on six patients, including initial GI and neurologic symptoms, histology of skeletal muscle biopsies, mitochondrial DNA mutational analysis, OXPHOS enzyme assay, upper GI barium imaging, technetium-99M liquid gastric emptying scan, upper GI endoscopy, esophageal manometry, and antroduodenal manometry. All six children presented with symptoms of GI dysmotility within 2 wk of life. Patients later developed symptoms of neurologic disorders. All patients had abnormalities in OXPHOS enzyme analysis. Muscle histology showed nonspecific changes with no ragged red fibers. Sequencing of the mitochondrial DNA showed no recognized mutations. No patient had any evidence of intestinal obstruction or malrotation by upper GI barium imaging. Four patients had delayed gastric emptying. Three patients had endoscopic and histologic evidence of esophagitis. All six had demonstrable neuropathic abnormalities by antroduodenal manometry, including the following: nonpropagated antral bursts, absent migrating motor complexes, postprandial antral hypomotility, retrograde migrating motor complexes, and tonic contractions with the migrating motor complex. Abnormalities in GI motility may be an early presenting sign of disorders of OXPHOS in children.
PLoS ONE, 2011
Gastrointestinal disturbances are commonly reported in children with autism, complicate clinical ... more Gastrointestinal disturbances are commonly reported in children with autism, complicate clinical management, and may contribute to behavioral impairment. Reports of deficiencies in disaccharidase enzymatic activity and of beneficial responses to probiotic and dietary therapies led us to survey gene expression and the mucoepithelial microbiota in intestinal biopsies from children with autism and gastrointestinal disease and children with gastrointestinal disease alone. Ileal transcripts encoding disaccharidases and hexose transporters were deficient in children with autism, indicating impairment of the primary pathway for carbohydrate digestion and transport in enterocytes. Deficient expression of these enzymes and transporters was associated with expression of the intestinal transcription factor, CDX2. Metagenomic analysis of intestinal bacteria revealed compositional dysbiosis manifest as decreases in Bacteroidetes, increases in the ratio of Firmicutes to Bacteroidetes, and increases in Betaproteobacteria. Expression levels of disaccharidases and transporters were associated with the abundance of affected bacterial phylotypes. These results indicate a relationship between human intestinal gene expression and bacterial community structure and may provide insights into the pathophysiology of gastrointestinal disturbances in children with autism.
PEDIATRICS, 2010
Children with autism spectrum disorders (ASDs) can benefit from adaptation of general pediatric g... more Children with autism spectrum disorders (ASDs) can benefit from adaptation of general pediatric guidelines for the diagnostic evaluation of abdominal pain, chronic constipation, and gastroesophageal reflux disease. These guidelines help health care providers determine when gastrointestinal symptoms are self-limited and when evaluation beyond a thorough medical history and physical examination should be considered. Children with ASDs who have gastrointestinal disorders may present with behavioral manifestations. Diagnostic and treatment recommendations for the general pediatric population are useful to consider until the development of evidence-based guidelines specifically for patients with ASDs. Pediatrics 2010;125:S19-S29
PEDIATRICS, 2010
Autism spectrum disorders (ASDs) are common and clinically heterogeneous neurodevelopmental disor... more Autism spectrum disorders (ASDs) are common and clinically heterogeneous neurodevelopmental disorders. Gastrointestinal disorders and associated symptoms are commonly reported in individuals with ASDs, but key issues such as the prevalence and best treatment of these conditions are incompletely understood. A central difficulty in recognizing and characterizing gastrointestinal dysfunction with ASDs is the communication difficulties experienced by many affected individuals. A multidisciplinary panel reviewed the medical literature with the aim of generating evidence-based recommendations for diagnostic evaluation and management of gastrointestinal problems in this patient population. The panel concluded that evidence-based recommendations are not yet available. The consensus expert opinion of the panel was that individuals with ASDs deserve the same thoroughness and standard of care in the diagnostic workup and treatment of gastrointestinal concerns as should occur for patients without ASDs. Care providers should be aware that problem behavior in patients with ASDs may be the primary or sole symptom of the underlying medical condition, including some gastrointestinal disorders. For these patients, integration of behavioral and medical care may be most beneficial. Priorities for future research are identified to advance our understanding and management of gastrointestinal disorders in persons with ASDs. Pediatrics 2010;125:S1-S18
PEDIATRICS, 2009
In addition to the core behavioral symptoms of autism spectrum disorder, many patients present wi... more In addition to the core behavioral symptoms of autism spectrum disorder, many patients present with complex medical conditions including gastrointestinal dysfunction. A functional variant in the promoter of the gene encoding the MET receptor tyrosine kinase is associated with autism spectrum disorder, and MET protein expression is decreased in the temporal cortex of subjects with autism spectrum disorder. MET is a pleiotropic receptor that functions in both brain development and gastrointestinal repair. On the basis of these functions, we hypothesized that association of the autism spectrum disorder-associated MET promoter variant may be enriched in a subset of individuals with co-occurring autism spectrum disorder and gastrointestinal conditions. Subjects were 918 individuals from 214 Autism Genetics Resource Exchange families with a complete medical history including gastrointestinal condition report. Genotypes at the autism spectrum disorder-associated MET promoter variant rs1858830 were determined. Family-based association test and chi(2) analyses were used to determine the association of MET rs1858830 alleles with autism spectrum disorder and the presence of gastrointestinal conditions. In the entire 214-family sample, the MET rs1858830 C allele was associated with both autism spectrum disorder and gastrointestinal conditions. Stratification by the presence of gastrointestinal conditions revealed that the MET C allele was associated with both autism spectrum disorder and gastrointestinal conditions in 118 families containing at least 1 child with co-occurring autism spectrum disorder and gastrointestinal conditions. In contrast, there was no association of the MET polymorphism with autism spectrum disorder in the 96 families lacking a child with co-occurring autism spectrum disorder and gastrointestinal conditions. chi(2) analyses of MET rs1858830 genotypes indicated over-representation of the C allele in individuals with co-occurring autism spectrum disorder and gastrointestinal conditions compared with non-autism spectrum disorder siblings, parents, and unrelated controls. These results suggest that disrupted MET signaling may contribute to increased risk for autism spectrum disorder that includes familial gastrointestinal dysfunction.
Gastroenterology, 2009
Gastroenterology, Volume 136, Issue 5, Pages A-676, May 2009, Authors:Shira Benor; George H. Russ... more Gastroenterology, Volume 136, Issue 5, Pages A-676, May 2009, Authors:Shira Benor; George H. Russell; Lauren A. Drake; Michael Silver; Timothy M. Buie; Stephen C. Hardy; Esther J. Israel; Gary J. Russell; Mark A. Salvatore; Qian Yuan; Garrett C. Zella; Harland S. Winter. ...
Behavioural Brain Research, 2013
Earlier identification and diagnosis of autism spectrum disorders (ASDs) can improve opportunitie... more Earlier identification and diagnosis of autism spectrum disorders (ASDs) can improve opportunities for children to benefit from intervention and lessen the burden on concerned parents. This review summarizes current knowledge about early signs of autism. Convergent data from both retrospective studies and prospective studies of high-risk infants indicate that ASD symptoms emerge in the first two years of life, affecting multiple developmental domains, mapping onto symptom dimensions consistent with current diagnostic frameworks including social-communication, and repetitive interests/behaviors but also extending to motor delays and atypical regulation of attention and emotion. Recent findings have shed new light on patterns of symptom onset and progression, and promise to inform early detection and diagnosis. Further attention to effective application of new findings and related challenges in building health system capacity to ensure timely access to specialized assessment and interventions is needed to fully realize the promise of improved outcomes resulting from this research.
PLoS ONE, 2008
Background: The presence of measles virus (MV) RNA in bowel tissue from children with autism spec... more Background: The presence of measles virus (MV) RNA in bowel tissue from children with autism spectrum disorders (ASD) and gastrointestinal (GI) disturbances was reported in 1998. Subsequent investigations found no associations between MV exposure and ASD but did not test for the presence of MV RNA in bowel or focus on children with ASD and GI disturbances. Failure to replicate the original study design may contribute to continued public concern with respect to the safety of the measles, mumps, and rubella (MMR) vaccine.
Pediatrics, 2015
Autism spectrum disorders (ASDs) are neurodevelopmental disorders characterized by impaired socia... more Autism spectrum disorders (ASDs) are neurodevelopmental disorders characterized by impaired social communication skills and isolated areas of interest. The current prevalence of these disorders is estimated to be 1 in 68, 2 and recent estimates of the risk of recurrence in families with at least 1 child diagnosed with ASD are 10% to 19%. Advances have been made in identifying genetic variants that can account for biological vulnerability to ASD, 6,7 although recent studies examining patterns of heredity implicate environmental factors and potential gene-by-environment interactions. 8 Although the exact etiology remains unknown in most families, some researchers suggest that the pathogenesis of the disorder begins during prenatal life. 9,10 It is likely that ASD is heterogeneous in its etiology as well as in its clinical presentation. 11
Pediatrics, 2015
This article reviews current evidence for autism spectrum disorder (ASD) screening based on peer-... more This article reviews current evidence for autism spectrum disorder (ASD) screening based on peer-reviewed articles published to December 2013. Screening provides a standardized process to ensure that children are systematically monitored for early signs of ASD to promote earlier diagnosis. The current review indicates that screening in children aged 18 to 24 months can assist in early detection, consistent with current American Academy of Pediatrics' recommendations. We identify ASD-specific and broadband screening tools that have been ev-aluated in large community samples which show particular promise in terms of accurate classification and clinical utility. We also suggest strategies to help overcome challenges to implementing ASD screening in community practice, as well as priorities for future research.
Pediatrics, 2015
This article reviews current evidence for autism spectrum disorder (ASD) interventions for childr... more This article reviews current evidence for autism spectrum disorder (ASD) interventions for children aged <3 years, based on peer-reviewed articles published up to December 2013. Several groups have adapted treatments initially designed for older, preschool-aged children with ASD, integrating best practice in behavioral teaching methods into a developmental framework based on current scientific understanding of how infants and toddlers learn. The central role of parents has been emphasized, and interventions are designed to incorporate learning opportunities into everyday activities, capitalize on "teachable moments," and facilitate the generalization of skills beyond the familiar home setting. Our review identified several comprehensive and targeted treatment models with evidence of clear benefits. Although some trials were limited to 8- to 12-week outcome data, enhanced outcomes associated with some interventions were evaluated over periods as long as 2 years. Based on...
The American Journal of Gastroenterology, 2003
Disorders of the mitochondrial electron transport chain enzymes of oxidative phosphorylation (OXP... more Disorders of the mitochondrial electron transport chain enzymes of oxidative phosphorylation (OXPHOS) have neurologic, musculoskeletal, ophthalmologic, cardiac, and GI manifestations. Many adult and pediatric patients with disorders of OXPHOS have abnormalities in intestinal motility. The purpose of this study was to describe pediatric patients who initially presented with signs of GI dysmotility and were later evaluated and found to have a disorder of OXPHOS. Data were collected on six patients, including initial GI and neurologic symptoms, histology of skeletal muscle biopsies, mitochondrial DNA mutational analysis, OXPHOS enzyme assay, upper GI barium imaging, technetium-99M liquid gastric emptying scan, upper GI endoscopy, esophageal manometry, and antroduodenal manometry. All six children presented with symptoms of GI dysmotility within 2 wk of life. Patients later developed symptoms of neurologic disorders. All patients had abnormalities in OXPHOS enzyme analysis. Muscle histology showed nonspecific changes with no ragged red fibers. Sequencing of the mitochondrial DNA showed no recognized mutations. No patient had any evidence of intestinal obstruction or malrotation by upper GI barium imaging. Four patients had delayed gastric emptying. Three patients had endoscopic and histologic evidence of esophagitis. All six had demonstrable neuropathic abnormalities by antroduodenal manometry, including the following: nonpropagated antral bursts, absent migrating motor complexes, postprandial antral hypomotility, retrograde migrating motor complexes, and tonic contractions with the migrating motor complex. Abnormalities in GI motility may be an early presenting sign of disorders of OXPHOS in children.
PLoS ONE, 2011
Gastrointestinal disturbances are commonly reported in children with autism, complicate clinical ... more Gastrointestinal disturbances are commonly reported in children with autism, complicate clinical management, and may contribute to behavioral impairment. Reports of deficiencies in disaccharidase enzymatic activity and of beneficial responses to probiotic and dietary therapies led us to survey gene expression and the mucoepithelial microbiota in intestinal biopsies from children with autism and gastrointestinal disease and children with gastrointestinal disease alone. Ileal transcripts encoding disaccharidases and hexose transporters were deficient in children with autism, indicating impairment of the primary pathway for carbohydrate digestion and transport in enterocytes. Deficient expression of these enzymes and transporters was associated with expression of the intestinal transcription factor, CDX2. Metagenomic analysis of intestinal bacteria revealed compositional dysbiosis manifest as decreases in Bacteroidetes, increases in the ratio of Firmicutes to Bacteroidetes, and increases in Betaproteobacteria. Expression levels of disaccharidases and transporters were associated with the abundance of affected bacterial phylotypes. These results indicate a relationship between human intestinal gene expression and bacterial community structure and may provide insights into the pathophysiology of gastrointestinal disturbances in children with autism.
PEDIATRICS, 2010
Children with autism spectrum disorders (ASDs) can benefit from adaptation of general pediatric g... more Children with autism spectrum disorders (ASDs) can benefit from adaptation of general pediatric guidelines for the diagnostic evaluation of abdominal pain, chronic constipation, and gastroesophageal reflux disease. These guidelines help health care providers determine when gastrointestinal symptoms are self-limited and when evaluation beyond a thorough medical history and physical examination should be considered. Children with ASDs who have gastrointestinal disorders may present with behavioral manifestations. Diagnostic and treatment recommendations for the general pediatric population are useful to consider until the development of evidence-based guidelines specifically for patients with ASDs. Pediatrics 2010;125:S19-S29
PEDIATRICS, 2010
Autism spectrum disorders (ASDs) are common and clinically heterogeneous neurodevelopmental disor... more Autism spectrum disorders (ASDs) are common and clinically heterogeneous neurodevelopmental disorders. Gastrointestinal disorders and associated symptoms are commonly reported in individuals with ASDs, but key issues such as the prevalence and best treatment of these conditions are incompletely understood. A central difficulty in recognizing and characterizing gastrointestinal dysfunction with ASDs is the communication difficulties experienced by many affected individuals. A multidisciplinary panel reviewed the medical literature with the aim of generating evidence-based recommendations for diagnostic evaluation and management of gastrointestinal problems in this patient population. The panel concluded that evidence-based recommendations are not yet available. The consensus expert opinion of the panel was that individuals with ASDs deserve the same thoroughness and standard of care in the diagnostic workup and treatment of gastrointestinal concerns as should occur for patients without ASDs. Care providers should be aware that problem behavior in patients with ASDs may be the primary or sole symptom of the underlying medical condition, including some gastrointestinal disorders. For these patients, integration of behavioral and medical care may be most beneficial. Priorities for future research are identified to advance our understanding and management of gastrointestinal disorders in persons with ASDs. Pediatrics 2010;125:S1-S18
PEDIATRICS, 2009
In addition to the core behavioral symptoms of autism spectrum disorder, many patients present wi... more In addition to the core behavioral symptoms of autism spectrum disorder, many patients present with complex medical conditions including gastrointestinal dysfunction. A functional variant in the promoter of the gene encoding the MET receptor tyrosine kinase is associated with autism spectrum disorder, and MET protein expression is decreased in the temporal cortex of subjects with autism spectrum disorder. MET is a pleiotropic receptor that functions in both brain development and gastrointestinal repair. On the basis of these functions, we hypothesized that association of the autism spectrum disorder-associated MET promoter variant may be enriched in a subset of individuals with co-occurring autism spectrum disorder and gastrointestinal conditions. Subjects were 918 individuals from 214 Autism Genetics Resource Exchange families with a complete medical history including gastrointestinal condition report. Genotypes at the autism spectrum disorder-associated MET promoter variant rs1858830 were determined. Family-based association test and chi(2) analyses were used to determine the association of MET rs1858830 alleles with autism spectrum disorder and the presence of gastrointestinal conditions. In the entire 214-family sample, the MET rs1858830 C allele was associated with both autism spectrum disorder and gastrointestinal conditions. Stratification by the presence of gastrointestinal conditions revealed that the MET C allele was associated with both autism spectrum disorder and gastrointestinal conditions in 118 families containing at least 1 child with co-occurring autism spectrum disorder and gastrointestinal conditions. In contrast, there was no association of the MET polymorphism with autism spectrum disorder in the 96 families lacking a child with co-occurring autism spectrum disorder and gastrointestinal conditions. chi(2) analyses of MET rs1858830 genotypes indicated over-representation of the C allele in individuals with co-occurring autism spectrum disorder and gastrointestinal conditions compared with non-autism spectrum disorder siblings, parents, and unrelated controls. These results suggest that disrupted MET signaling may contribute to increased risk for autism spectrum disorder that includes familial gastrointestinal dysfunction.
Gastroenterology, 2009
Gastroenterology, Volume 136, Issue 5, Pages A-676, May 2009, Authors:Shira Benor; George H. Russ... more Gastroenterology, Volume 136, Issue 5, Pages A-676, May 2009, Authors:Shira Benor; George H. Russell; Lauren A. Drake; Michael Silver; Timothy M. Buie; Stephen C. Hardy; Esther J. Israel; Gary J. Russell; Mark A. Salvatore; Qian Yuan; Garrett C. Zella; Harland S. Winter. ...
Behavioural Brain Research, 2013
Earlier identification and diagnosis of autism spectrum disorders (ASDs) can improve opportunitie... more Earlier identification and diagnosis of autism spectrum disorders (ASDs) can improve opportunities for children to benefit from intervention and lessen the burden on concerned parents. This review summarizes current knowledge about early signs of autism. Convergent data from both retrospective studies and prospective studies of high-risk infants indicate that ASD symptoms emerge in the first two years of life, affecting multiple developmental domains, mapping onto symptom dimensions consistent with current diagnostic frameworks including social-communication, and repetitive interests/behaviors but also extending to motor delays and atypical regulation of attention and emotion. Recent findings have shed new light on patterns of symptom onset and progression, and promise to inform early detection and diagnosis. Further attention to effective application of new findings and related challenges in building health system capacity to ensure timely access to specialized assessment and interventions is needed to fully realize the promise of improved outcomes resulting from this research.
PLoS ONE, 2008
Background: The presence of measles virus (MV) RNA in bowel tissue from children with autism spec... more Background: The presence of measles virus (MV) RNA in bowel tissue from children with autism spectrum disorders (ASD) and gastrointestinal (GI) disturbances was reported in 1998. Subsequent investigations found no associations between MV exposure and ASD but did not test for the presence of MV RNA in bowel or focus on children with ASD and GI disturbances. Failure to replicate the original study design may contribute to continued public concern with respect to the safety of the measles, mumps, and rubella (MMR) vaccine.