Publications by authors named "Ryan Richholt"

Article Synopsis
  • Mutations in the X-linked gene that encodes methyl-CpG-binding protein 2 are known to cause classical Rett syndrome (RTT) primarily in girls, while some patients present a 'Rett-syndrome-like phenotype' (RTT-L) without the typical mutations.
  • The study reports on eight patients diagnosed with RTT-L who have mutations in genes not directly linked to classical RTT, and analyzes their genetic data along with insights from existing research to build a comprehensive network of protein interactions involving RTT and RTT-L genes.
  • Functional analysis reveals key biological processes associated with these genes, highlighting the roles of specific transcription factors and suggesting that proteins HDAC1 and CHD4 may play crucial roles in the interaction network between RTT
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Circular RNA (circRNA) are a recently discovered class of RNA characterized by a covalently-bonded back-splice junction. As circRNAs are inherently more stable than other RNA species, they may be detected extracellularly in peripheral biofluids and provide novel biomarkers. While circRNA have been identified previously in peripheral biofluids, there are few datasets for circRNA junctions from healthy controls.

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Biomarkers that predict symptom trajectories after trauma can facilitate early detection or intervention for posttraumatic stress disorder (PTSD) and may also advance our understanding of its biology. Here, we aimed to identify trajectory-based biomarkers using blood transcriptomes collected in the immediate aftermath of trauma exposure. Participants were recruited from an Emergency Department in the immediate aftermath of trauma exposure and assessed for PTSD symptoms at baseline, 1, 3, 6, and 12 months.

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We developed and analytically validated a comprehensive genomic profiling (CGP) assay, GEM ExTra, for patients with advanced solid tumors that uses Next Generation Sequencing (NGS) to characterize whole exomes employing a paired tumor-normal subtraction methodology. The assay detects single nucleotide variants (SNV), indels, focal copy number alterations (CNA), TERT promoter region, as well as tumor mutation burden (TMB) and microsatellite instability (MSI) status. Additionally, the assay incorporates whole transcriptome sequencing of the tumor sample that allows for the detection of gene fusions and select special transcripts, including AR-V7, EGFR vIII, EGFRvIV, and MET exon 14 skipping events.

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Background: Whether brain-derived neurotrophic factor (BDNF) Met carriage impacts the risk or progression of Alzheimer's disease (AD) is unknown.

Objective: To evaluate the interaction of BDNF Met and APOE4 carriage on cerebral metabolic rate for glucose (CMRgl), amyloid burden, hippocampus volume, and cognitive decline among cognitively unimpaired (CU) adults enrolled in the Arizona APOE cohort study.

Methods: 114 CU adults (mean age 56.

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Objective: Description of a new variant of the glutamine-fructose-6-phosphate transaminase 1 () gene causing congenital myasthenic syndrome (CMS) in 3 children from 2 unrelated families.

Methods: Muscle biopsies, EMG, and whole-exome sequencing were performed.

Results: All 3 patients presented with congenital hypotonia, muscle weakness, respiratory insufficiency, head lag, areflexia, and gastrointestinal dysfunction.

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Article Synopsis
  • Pelizaeus-Merzbacher-like disease (PMLD) is a genetic disorder marked by neurological issues like early-onset nystagmus, developmental delays, and spasticity, resembling another condition called Pelizaeus-Merzbacher disease (PMD).
  • A study reported a 12-year-old boy exhibiting classic PMLD symptoms and MRI results indicating severe myelination issues, linked to mutations in the SNAP29 gene.
  • The research highlights that mutations in SNAP29, previously associated with a different syndrome (CEDNIK), can also contribute to PMLD, broadening our understanding of the disease's genetic causes.
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Article Synopsis
  • * The variants disrupt DDX6's function in processing bodies, which are critical for mRNA regulation, leading to defective assembly and interactions with protein partners in cell lines.
  • * Findings suggest that DDX6 could be linked to a neurodevelopmental syndrome and should be included in the growing category of disorders associated with RNA helicases, alongside DDX3X and DHX30.
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Osteosarcoma (OS) is a rare, metastatic, human adolescent cancer that also occurs in pet dogs. To define the genomic underpinnings of canine OS, we performed multi-platform analysis of OS tumors from 59 dogs, including whole genome sequencing ( = 24) and whole exome sequencing (WES;  = 13) of primary tumors and matched normal tissue, WES ( = 10) of matched primary/metastatic/normal samples and RNA sequencing ( = 54) of primary tumors. We found that canine OS recapitulates features of human OS including low point mutation burden (median 1.

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Chromosome 1q41-q42 deletions have recently been associated with a recognizable neurodevelopmental syndrome of early childhood (OMIM 612530). Within this group, a predominant phenotype of developmental delay (DD), intellectual disability (ID), epilepsy, distinct dysmorphology, and brain anomalies on magnetic resonance imaging/computed tomography has emerged. Previous reports of patients with de novo deletions at 1q41-q42 have led to the identification of an evolving smallest region of overlap which has included several potentially causal genes including DISP1, TP53BP2, and FBXO28.

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Epileptic encephalopathies are childhood brain disorders characterized by a variety of severe epilepsy syndromes that differ by the age of onset and seizure type. Until recently, the cause of many epileptic encephalopathies was unknown. Whole exome or whole genome sequencing has led to the identification of several causal genes in individuals with epileptic encephalopathy, and the list of genes has now expanded greatly.

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: SuperAgers are adults age 80+ with episodic memory performance that is as good as that of average middle-aged adults. Understanding the biological determinants of SuperAging may have relevance to preventing age-related cognitive decline and dementia. This study aimed to identify associations between genetic variations and the SuperAging phenotype using Whole Exome Sequencing (WES).

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The resource modulation hypothesis suggests that the influence of genes on cognitive functioning increases with age. The single nucleotide polymorphism rs17070145, associated with episodic memory and working memory, has been suggested to follow such a pattern, but few studies have tested this assertion directly. The present study investigated the relationship between alleles (T carriers vs.

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Aim: To explore differential DNA methylation (DNAm) in Aicardi syndrome (AIC), a severe neurodevelopmental disorder with largely unknown etiology.

Patients & Methods: We characterized DNAm in AIC female patients and parents using the Illumina 450 K array. Differential DNAm was assessed using the local outlier factor algorithm, and results were validated via qPCR in a larger set of AIC female patients, parents and unrelated young female controls.

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Mutations disrupting presynaptic protein TBC1D24 are associated with a variable neurological phenotype, including DOORS syndrome, myoclonic epilepsy, early-infantile epileptic encephalopathy, and non-syndromic hearing loss. In this report, we describe a family segregating autosomal dominant epilepsy, and a 37-year-old Caucasian female with a severe neurological phenotype including epilepsy, Parkinsonism, psychosis, visual and auditory hallucinations, gait ataxia and intellectual disability. Whole exome sequencing revealed two missense mutations in the gene segregating within this family (c.

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Interest in circulating RNAs for monitoring and diagnosing human health has grown significantly. There are few datasets describing baseline expression levels for total cell-free circulating RNA from healthy control subjects. In this study, total extracellular RNA (exRNA) was isolated and sequenced from 183 plasma samples, 204 urine samples and 46 saliva samples from 55 male college athletes ages 18-25 years.

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Recently, mutations in the zinc finger MYND-type containing 11 (ZMYND11) gene were identified in patients with autism spectrum disorders, intellectual disability, aggression, and complex neuropsychiatric features, supporting that this gene is implicated in 10p15.3 microdeletion syndrome. We report a novel de novo variant in the ZMYND11 gene (p.

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Objective: To determine the phenotypic spectrum caused by mutations in GRIN1 encoding the NMDA receptor subunit GluN1 and to investigate their underlying functional pathophysiology.

Methods: We collected molecular and clinical data from several diagnostic and research cohorts. Functional consequences of GRIN1 mutations were investigated in Xenopus laevis oocytes.

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The proteins encoded by TELO2, TTI1, and TTI2 interact to form the TTT complex, a co-chaperone for maturation of the phosphatidylinositol 3-kinase-related protein kinases (PIKKs). Here we report six affected individuals from four families with intellectual disability (ID) and neurological and other congenital abnormalities associated with compound heterozygous variants in TELO2. Although their fibroblasts showed reduced steady-state levels of TELO2 and the other components of the TTT complex, PIKK functions were normal in cellular assays.

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Background: Stress-induced cardiomyopathy (SIC) is a poorly understood condition associated with periods of emotional and physical stress. The clinical approaches for management of SIC are supportive and reactive to patient symptoms.

Objective: To utilize next-generation exome sequencing to define genetic variation associated with, and potentially responsible for, this disease.

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A 3-year-old female patient presenting with an unknown syndrome of a neonatal progeroid appearance, lipodystrophy, pulmonary hypertension, cutis marmorata, feeding disorder and failure to thrive was investigated by whole-genome sequencing. This revealed a de novo, heterozygous, frame-shift mutation in the Caveolin1 gene (CAV1) (p.Phe160X).

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Purpose: Aicardi syndrome (AIC) is a congenital neurodevelopmental disorder characterized by infantile spasms, agenesis of the corpus callosum, and chorioretinal lacunae. Variation in phenotype and disease severity is well documented, but chorioretinal lacunae represent the most constant pathological feature. Aicardi syndrome is believed to be an X-linked-dominant disorder occurring almost exclusively in females, although 46, XY males with AIC have been described.

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