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PURPOSE: To identify genetic etiologies and genotype/phenotype associations for unsolved ocular congenital cranial dysinnervation disorders (oCCDDs). METHODS: We coupled phenotyping with exome or genome sequencing of 467 probands (550 affected and 1108 total individuals) with genetically unsolved oCCDDs, integrating analyses of pedigrees, human and animal model phenotypes, and de novo variants to identify rare candidate single nucleotide variants, insertion/deletions, and structural variants disrupting protein-coding regions. Prioritized variants were classified for pathogenicity and evaluated for genotype/phenotype correlations. RESULTS: Analyses elucidated phenotypic subgroups, identified pathogenic/likely pathogenic variant(s) in 43/467 probands (9.2%), and prioritized variants of uncertain significance in 70/467 additional probands (15.0%). These included known and novel variants in established oCCDD genes, genes associated with syndromes that sometimes include oCCDDs (e.g., MYH10, KIF21B, TGFBR2, TUBB6), genes that fit the syndromic component of the phenotype but had no prior oCCDD association (e.g., CDK13, TGFB2), genes with no reported association with oCCDDs or the syndromic phenotypes (e.g., TUBA4A, KIF5C, CTNNA1, KLB, FGF21), and genes associated with oCCDD phenocopies that had resulted in misdiagnoses. CONCLUSION: This study suggests that unsolved oCCDDs are clinically and genetically heterogeneous disorders often overlapping other Mendelian conditions and nominates many candidates for future replication and functional studies.
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Congenital fibrosis of the extraocular muscles (CFEOM) type 1 is associated with heterozygous missense variants in KIF21A, which encodes a kinesin-like motor protein. Individuals with CFEOM1 have severe paralysis of upgaze and ptosis, resulting in a pronounced chin-up head posture. There can also be limitations of horizontal eye movements. Loss of function of KIF26A, an unconventional kinesin motor protein that lacks ATP-dependent motor activity, has been recently reported to cause a spectrum of congenital brain malformations associated with defects in migration, localization, and growth of excitatory neurons. It has also been associated with megacolon resembling Hirschsprung's disease. We report the case of a boy with homozygous loss of function of KIF26A with restricted eye movements, specifically restricted upgaze and downgaze with variable nystagmus and dissociated vertical eye movements. This case represents a congenital cranial dysinnervation disorder, most similar to CFEOM, and is the first report of a congenital cranial dysinnervation disorder caused by a kinesin other than KIF21A.
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Homozigoto , Cinesinas , Humanos , Masculino , Cinesinas/genética , Movimentos Oculares/fisiologia , Transtornos da Motilidade Ocular/genética , Transtornos da Motilidade Ocular/diagnóstico , Transtornos da Motilidade Ocular/fisiopatologia , Músculos Oculomotores/anormalidades , Músculos Oculomotores/fisiopatologia , Músculos Oculomotores/inervação , Transtornos Congênitos de Denervação Craniana , OftalmoplegiaRESUMO
Purpose: To determine whether development of neuromuscular junctions (NMJs) differs between extraocular muscles (EOMs) and other skeletal muscles. Methods: Mouse EOMs, diaphragm, and tibialis anterior (TA) were collected at postnatal day (P)0, P3, P7, P10, P14, and P21, and 12 weeks. Whole muscles were stained with α-bungarotoxin, anti-neurofilament antibody, and slow or fast myosin heavy chain antibody, and imaged with a confocal microscope. Images were quantified using Imaris software. Results: NMJs in the EOMs show a unique pattern of morphological development compared to diaphragm and TA. At P0, diaphragm and TA NMJs were oval plaques; EOM single NMJs were long, thin rods. NMJs in the three muscle types progress to mature morphology at different rates. At all ages, EOM single NMJs were larger, especially relative to myofiber size. The inferior oblique and inferior rectus muscles show delayed single NMJ development compared to other EOMs. NMJs on multiply-innervated fibers in the EOMs vary widely in size, and there were no consistent differences between muscles or over time. Incoming motor nerves formed complex branching patterns, dividing first into superficial and deep branches, each of which branched extensively over the full width of the muscle. Motor axons that innervate multiply-innervated fibers entered the muscle with the axons that innervate singly-innervated fibers, then extended both proximally and distally. EOM NMJs had more subsynaptic nuclei than skeletal muscle NMJs throughout development. Conclusions: EOMs show a unique pattern of NMJ development and have more subsynaptic nuclei than other muscles, which may contribute to the exquisite control of eye movements.
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Microscopia Confocal , Músculo Esquelético , Junção Neuromuscular , Músculos Oculomotores , Animais , Músculos Oculomotores/inervação , Músculos Oculomotores/crescimento & desenvolvimento , Camundongos , Camundongos Endogâmicos C57BL , Cadeias Pesadas de Miosina/metabolismo , Animais Recém-Nascidos , FemininoRESUMO
Purpose: To identify genetic etiologies and genotype/phenotype associations for unsolved ocular congenital cranial dysinnervation disorders (oCCDDs). Methods: We coupled phenotyping with exome or genome sequencing of 467 pedigrees with genetically unsolved oCCDDs, integrating analyses of pedigrees, human and animal model phenotypes, and de novo variants to identify rare candidate single nucleotide variants, insertion/deletions, and structural variants disrupting protein-coding regions. Prioritized variants were classified for pathogenicity and evaluated for genotype/phenotype correlations. Results: Analyses elucidated phenotypic subgroups, identified pathogenic/likely pathogenic variant(s) in 43/467 probands (9.2%), and prioritized variants of uncertain significance in 70/467 additional probands (15.0%). These included known and novel variants in established oCCDD genes, genes associated with syndromes that sometimes include oCCDDs (e.g., MYH10, KIF21B, TGFBR2, TUBB6), genes that fit the syndromic component of the phenotype but had no prior oCCDD association (e.g., CDK13, TGFB2), genes with no reported association with oCCDDs or the syndromic phenotypes (e.g., TUBA4A, KIF5C, CTNNA1, KLB, FGF21), and genes associated with oCCDD phenocopies that had resulted in misdiagnoses. Conclusion: This study suggests that unsolved oCCDDs are clinically and genetically heterogeneous disorders often overlapping other Mendelian conditions and nominates many candidates for future replication and functional studies.
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Importance: Greater understanding of the association between strabismus and mental health conditions across sociodemographic backgrounds may inform strategies to improve mental well-being in this population. Objective: To describe the association of strabismus with mental health conditions in a diverse cohort of US adults. Design, Setting, and Participants: This cross-sectional study used data from the National Institutes of Health's All of Us Research Program, an ongoing program launched in 2015. The study included 3646 adults (aged ≥18 years) with strabismus and 3646 propensity score-matched controls. Statistical analysis was conducted from September 12, 2023, to January 29, 2024. Main Outcomes and Measures: Adults with strabismus were propensity score matched on age, gender, race and ethnicity, income, educational level, and insurance status in a 1:1 ratio with adults without strabismus. The prevalences of anxiety, depression, substance use and addiction, bipolar disorder, and schizophrenia spectrum disorder among adults with strabismus were compared with controls. Logistic regression was used to evaluate the association of mental health conditions with sociodemographic factors in each group. Results: This study included 3646 adults with strabismus (median age, 67 years [IQR, 53-76 years]; 2017 women [55%]) and 3646 propensity score-matched controls (median age, 67 years [IQR, 53-76 years]; 2017 women [55%]). Individuals with strabismus had higher prevalences of anxiety (1153 [32%] vs 519 [14%]; difference, 17%; 95% CI, 15%-19%; P < .001), depression (1189 [33%] vs 514 [14%]; difference, 19%; 95% CI, 17%-20%; P < .001), substance use and addiction (116 [3%] vs 51 [1%]; difference, 2%; 95% CI, 1%-3%; P < .001), bipolar disorder (253 [7%] vs 101 [3%]; difference, 4%; 95% CI, 3%-5%; P < .001), and schizophrenia spectrum disorder (103 [3%] vs 36 [1%]; difference, 2%; 95% CI, 1%-3%; P < .001) compared with individuals without strabismus. Among adults with strabismus, higher odds of mental health conditions were associated with younger age (odds ratio [OR], 1.11 per 10-year decrease; 95% CI, 1.06-1.16 per 10-year decrease), female gender (OR, 1.62; 95% CI, 1.41-1.85), Black or African American race and ethnicity (OR, 1.22; 95% CI, 1.01-1.48), low income (OR, 3.06; 95% CI, 2.56-3.67), and high school education or less (OR, 1.58; 95% CI, 1.34-1.85). Conclusions and Relevance: In a diverse and nationwide cohort, adults with strabismus were more likely to have mental health conditions compared with adults without strabismus. Further investigation into the risk factors for poor mental health among adults with strabismus across sociodemographic backgrounds may offer novel opportunities for interventions to improve mental well-being in this population.
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Saúde Mental , Estrabismo , Humanos , Masculino , Feminino , Estrabismo/epidemiologia , Estrabismo/psicologia , Estudos Transversais , Pessoa de Meia-Idade , Estados Unidos/epidemiologia , Adulto , Prevalência , Idoso , Transtornos Mentais/epidemiologia , Adulto Jovem , Pontuação de Propensão , AdolescenteRESUMO
Importance: Strabismus is a common ocular disorder of childhood. There is a clear genetic component to strabismus, but it is not known if esotropia and exotropia share genetic risk factors. Objective: To determine whether genetic duplications associated with esotropia are also associated with exotropia. Design, Setting, and Participants: This was a cross-sectional study conducted from November 2005 to December 2023. Individuals with constant or intermittent exotropia of any magnitude or a history of surgery for exotropia were recruited from pediatric ophthalmic practices. Data were analyzed from March to December 2023. Exposure: Genetic duplication. Main Outcomes and Measures: Presence of genetic duplications at 2p11.2, 4p15.2, and 10q11.22 assessed by digital droplet polymerase chain reaction. Orthoptic measurements and history of strabismus surgery were performed. Results: A total of 234 individuals (mean [SD] age, 19.5 [19.0] years; 127 female [54.3%]) were included in this study. The chromosome 2 duplication was present in 1.7% of patients with exotropia (4 of 234; P = .40), a similar proportion to the 1.4% of patients with esotropia (23 of 1614) in whom it was previously reported and higher than the 0.1% of controls (4 of 3922) previously reported (difference, 1.6%; 95% CI, 0%-3.3%; P < .001). The chromosome 4 duplication was present in 3.0% of patients with exotropia (7 of 234; P = .10), a similar proportion to the 1.7% of patients with esotropia (27 of 1614) and higher than the 0.2% of controls (6 of 3922) in whom it was previously reported (difference, 2.8%; 95% CI, 0.6%-5.0%; P < .001). The chromosome 10 duplication was present in 6.0% of patients with exotropia (14 of 234; P = .08), a similar proportion to the 4% of patients with esotropia (64 of 1614) and higher than the 0.4% of controls (18 of 3922) in whom it was previously reported (difference, 5.6%; 95% CI, 2.5%-8.6%; P < .001). Individuals with a duplication had higher mean (SD) magnitude of deviation (31 [13] vs 22 [14] prism diopters [PD]; difference, 9 PD; 95% CI, 1-16 PD; P = .03), were more likely to have constant (vs intermittent) exotropia (70% vs 29%; difference, 41%; 95% CI, 20.8%-61.2%; P < .001), and had a higher rate of exotropia surgery than those without a duplication (58% vs 34%; difference, 24%; 95% CI, 3%-44%; P = .02). Conclusions and Relevance: In this cross-sectional study, results suggest that the genetic duplications on chromosomes 2, 4, and 10 were risk factors for exotropia as well as esotropia. These findings support the possibility that esotropia and exotropia have shared genetic risk factors. Whether esotropia or exotropia develops in the presence of these duplications may be influenced by other shared or independent genetic variants or by environmental factors.
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Esotropia , Exotropia , Estrabismo , Humanos , Criança , Feminino , Adulto Jovem , Adulto , Esotropia/genética , Esotropia/cirurgia , Exotropia/genética , Estudos Transversais , Variações do Número de Cópias de DNA , Músculos Oculomotores/cirurgia , Genótipo , FenótipoRESUMO
Hereditary congenital facial paresis type 1 (HCFP1) is an autosomal dominant disorder of absent or limited facial movement that maps to chromosome 3q21-q22 and is hypothesized to result from facial branchial motor neuron (FBMN) maldevelopment. In the present study, we report that HCFP1 results from heterozygous duplications within a neuron-specific GATA2 regulatory region that includes two enhancers and one silencer, and from noncoding single-nucleotide variants (SNVs) within the silencer. Some SNVs impair binding of NR2F1 to the silencer in vitro and in vivo and attenuate in vivo enhancer reporter expression in FBMNs. Gata2 and its effector Gata3 are essential for inner-ear efferent neuron (IEE) but not FBMN development. A humanized HCFP1 mouse model extends Gata2 expression, favors the formation of IEEs over FBMNs and is rescued by conditional loss of Gata3. These findings highlight the importance of temporal gene regulation in development and of noncoding variation in rare mendelian disease.
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Paralisia Facial , Animais , Camundongos , Paralisia Facial/genética , Paralisia Facial/congênito , Paralisia Facial/metabolismo , Fator de Transcrição GATA2/genética , Fator de Transcrição GATA2/metabolismo , Neurônios Motores/metabolismo , Neurogênese , Neurônios EferentesRESUMO
Strabismus, or misalignment of the eyes, is the most common ocular disorder in the pediatric population, affecting approximately 2%-4% of children. Strabismus leads to the disruption of binocular vision, amblyopia, social and occupational discrimination, and decreased quality of life. Although it has been recognized since ancient times that strabismus runs in families, its inheritance patterns are complex, and its precise genetic mechanisms have not yet been defined. Family, population, and twin studies all support a role of genetics in the development of strabismus. There are multiple forms of strabismus, and it is not known if they have shared genetic mechanisms or are distinct genetic disorders, which complicates studies of strabismus. Studies assuming that strabismus is a Mendelian disorder have found areas of linkage and candidate genes in particular families, but no definitive causal genes. Genome-wide association studies searching for common variation that contributes to strabismus risk have identified two risk loci and three copy number variants in white populations. Causative genes have been identified in congenital cranial dysinnervation disorders, syndromes in which eye movement is limited or paralyzed. The causative genes lead to either improper differentiation of cranial motor neurons or abnormal axon guidance. This article reviews the evidence for a genetic contribution to strabismus and the recent advances that have been made in the genetics of comitant strabismus, the most common form of strabismus.
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Purpose: To determine if extraocular muscles (EOMs) from mice with nystagmus show abnormalities in myofiber composition and innervation, as seen in EOMs from human nystagmus patients, and to determine when in development those changes occur. Methods: Balb/c albino mice were crossed to pigmented mice to generate heterozygous mice, which were mated to create experimental litters containing albinos and wild-type controls. Orbits were harvested from adult animals (12 weeks old); on postnatal day (P)0, P10, P14, and P21; and from 6-week-old animals. EOM sections were collected from the intraorbital portion of the muscles. Sections were immunostained for slow and fast myosin and for neuromuscular junctions (NMJs). The proportion of each myofiber subtype and the density and size of NMJs were quantified. Initial innervation patterns were assessed using whole-mount immunostaining of embryonic day (E)13.5 embryos expressing IslMN:GFP. Results: Adult albino EOMs display an increased proportion of slow myofibers, larger slow myofibers, and a decreased density of NMJs-similar to human nystagmus patients. The percentage of NMJs on slow myofibers is also lower in albino animals. The initial innervation pattern of the incoming ocular motor neurons is normal in E13.5 albino embryos. Differences in the proportion of slow and fast myofiber subtypes are present as early as P14, and a lower percentage of NMJs on slow myofibers is present by P21. There is a lower density of NMJs on albino EOMs as early as P10, prior to eye opening. Conclusions: Changes in NMJ development observed before eye opening indicate that nystagmus is not solely secondary to poor vision.
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Nistagmo Patológico , Músculos Oculomotores , Adulto , Animais , Modelos Animais de Doenças , Olho , Humanos , Camundongos , Neurônios Motores , Junção Neuromuscular , Músculos Oculomotores/inervaçãoRESUMO
Heterozygous loss of function mutations in TWIST1 cause Saethre-Chotzen syndrome, which is characterized by craniosynostosis, facial asymmetry, ptosis, strabismus, and distinctive ear appearance. Individuals with syndromic craniosynostosis have high rates of strabismus and ptosis, but the underlying pathology is unknown. Some individuals with syndromic craniosynostosis have been noted to have absence of individual extraocular muscles or abnormal insertions of the extraocular muscles on the globe. Using conditional knock-out alleles for Twist1 in cranial mesenchyme, we test the hypothesis that Twist1 is required for extraocular muscle organization and position, attachment to the globe, and/or innervation by the cranial nerves. We examined the extraocular muscles in conditional Twist1 knock-out animals using Twist2-cre and Pdgfrb-cre drivers. Both are expressed in cranial mesoderm and neural crest. Conditional inactivation of Twist1 using these drivers leads to disorganized extraocular muscles that cannot be reliably identified as specific muscles. Tendons do not form normally at the insertion and origin of these dysplastic muscles. Knock-out of Twist1 expression in tendon precursors, using scleraxis-cre, however, does not alter EOM organization. Furthermore, developing motor neurons, which do not express Twist1, display abnormal axonal trajectories in the orbit in the presence of dysplastic extraocular muscles. Strabismus in individuals with TWIST1 mutations may therefore be caused by abnormalities in extraocular muscle development and secondary abnormalities in innervation and tendon formation.
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Acrocefalossindactilia , Craniossinostoses , Estrabismo , Proteína 1 Relacionada a Twist , Acrocefalossindactilia/complicações , Acrocefalossindactilia/genética , Animais , Craniossinostoses/genética , Camundongos , Crista Neural , Músculos Oculomotores , Estrabismo/complicações , Proteína 1 Relacionada a Twist/genéticaRESUMO
PURPOSE: Identify demographic and clinical characteristics at the first presentation associated with later having surgery for intermittent exotropia (IXT). METHODS: Retrospective cohort study of 228 children with IXT and 5+ years of follow-up. Demographic and clinical data were extracted from medical records. A total 97 participants who underwent surgery during follow-up were compared to 131 participants who did not. Best subset regression was used to identify first visit variables associated with later having strabismus surgery. Surgery was then regressed on the selected variables using logistic models. RESULTS: Age and control were the only first visit variables significantly associated with having surgery for IXT. Notably, neither angle of deviation nor stereopsis were associated with later surgery. In an adjusted logistic model, each one-month increase in age at presentation was associated with a 1% decrease in the odds of having surgery (OR = 0.991, 95% CI: 0.982-0.999, P = .04). Children with poor control at initial visit had almost five times greater odds of having surgery than those with good control (OR = 4.95, 95% CI: 2.31-10.98, P < .0001). CONCLUSIONS: Age and control of IXT are important factors at presentation associated with future surgical intervention for IXT. The magnitude of deviation and stereopsis was not significantly associated with future surgical treatment for IXT.
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Exotropia , Criança , Doença Crônica , Percepção de Profundidade , Exotropia/cirurgia , Humanos , Músculos Oculomotores/cirurgia , Estudos RetrospectivosRESUMO
Microtubules are formed from heterodimers of alpha- and beta-tubulin, each of which has multiple isoforms encoded by separate genes. Pathogenic missense variants in multiple different tubulin isoforms cause brain malformations. Missense mutations in TUBB3, which encodes the neuron-specific beta-tubulin isotype, can cause congenital fibrosis of the extraocular muscles type 3 (CFEOM3) and/or malformations of cortical development, with distinct genotype-phenotype correlations. Here, we report fourteen individuals from thirteen unrelated families, each of whom harbors the identical NM_006086.4 (TUBB3):c.785G>A (p.Arg262His) variant resulting in a phenotype we refer to as the TUBB3 R262H syndrome. The affected individuals present at birth with ptosis, ophthalmoplegia, exotropia, facial weakness, facial dysmorphisms, and, in most cases, distal congenital joint contractures, and subsequently develop intellectual disabilities, gait disorders with proximal joint contractures, Kallmann syndrome (hypogonadotropic hypogonadism and anosmia), and a progressive peripheral neuropathy during the first decade of life. Subsets may also have vocal cord paralysis, auditory dysfunction, cyclic vomiting, and/or tachycardia at rest. All fourteen subjects share a recognizable set of brain malformations, including hypoplasia of the corpus callosum and anterior commissure, basal ganglia malformations, absent olfactory bulbs and sulci, and subtle cerebellar malformations. While similar, individuals with the TUBB3 R262H syndrome can be distinguished from individuals with the TUBB3 E410K syndrome by the presence of congenital and acquired joint contractures, an earlier onset peripheral neuropathy, impaired gait, and basal ganglia malformations.
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Paralisia Facial/genética , Fibrose/genética , Mutação , Oftalmoplegia/genética , Doenças do Sistema Nervoso Periférico/genética , Tubulina (Proteína)/genética , Anormalidades Múltiplas/genética , Adolescente , Adulto , Substituição de Aminoácidos , Arginina , Criança , Pré-Escolar , Paralisia Facial/diagnóstico , Paralisia Facial/fisiopatologia , Feminino , Fibrose/diagnóstico , Fibrose/fisiopatologia , Histidina , Humanos , Lactente , Masculino , Oftalmoplegia/diagnóstico , Oftalmoplegia/fisiopatologia , Doenças do Sistema Nervoso Periférico/diagnóstico , Doenças do Sistema Nervoso Periférico/fisiopatologia , Síndrome , Adulto JovemRESUMO
Abnormalities in cranial motor nerve development cause paralytic strabismus syndromes, collectively referred to as congenital cranial dysinnervation disorders, in which patients cannot fully move their eyes. These disorders can arise through one of two mechanisms: (a) defective motor neuron specification, usually by loss of a transcription factor necessary for brainstem patterning, or (b) axon growth and guidance abnormalities of the oculomotor, trochlear, and abducens nerves. This review focuses on our current understanding of axon guidance mechanisms in the cranial motor nerves and how disease-causing mutations disrupt axon targeting. Abnormalities of axon growth and guidance are often limited to a single nerve or subdivision, even when the causative gene is ubiquitously expressed. Additionally, when one nerve is absent, its normal target muscles attract other motor neurons. Study of these disorders highlights the complexities of axon guidance and how each population of neurons uses a unique but overlapping set of axon guidance pathways.
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Doenças dos Nervos Cranianos , Estrabismo , Axônios , Doenças dos Nervos Cranianos/metabolismo , Movimentos Oculares , Humanos , Neurônios Motores/metabolismoRESUMO
Variants in multiple tubulin genes have been implicated in neurodevelopmental disorders, including malformations of cortical development (MCD) and congenital fibrosis of the extraocular muscles (CFEOM). Distinct missense variants in the beta-tubulin encoding genes TUBB3 and TUBB2B cause MCD, CFEOM, or both, suggesting substitution-specific mechanisms. Variants in the alpha tubulin-encoding gene TUBA1A have been associated with MCD, but not with CFEOM. Using exome sequencing (ES) and genome sequencing (GS), we identified 3 unrelated probands with CFEOM who harbored novel heterozygous TUBA1A missense variants c.1216C>G, p.(His406Asp); c.467G>A, p.(Arg156His); and c.1193T>G, p.(Met398Arg). MRI revealed small oculomotor-innervated muscles and asymmetrical caudate heads and lateral ventricles with or without corpus callosal thinning. Two of the three probands had MCD. Mutated amino acid residues localize either to the longitudinal interface at which α and ß tubulins heterodimerize (Met398, His406) or to the lateral interface at which tubulin protofilaments interact (Arg156), and His406 interacts with the motor domain of kinesin-1. This series of individuals supports TUBA1A variants as a cause of CFEOM and expands our knowledge of tubulinopathies.
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Fibrose/genética , Malformações do Desenvolvimento Cortical/genética , Oftalmoplegia/genética , Tubulina (Proteína)/genética , Adolescente , Sítios de Ligação , Criança , Feminino , Fibrose/patologia , Heterozigoto , Humanos , Cinesinas/metabolismo , Masculino , Malformações do Desenvolvimento Cortical/patologia , Mutação de Sentido Incorreto , Oftalmoplegia/patologia , Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismoRESUMO
Purpose: To determine whether rare copy number variants (CNVs) increase risk for comitant esotropia. Methods: CNVs were identified in 1614 Caucasian individuals with comitant esotropia and 3922 Caucasian controls from Illumina SNP genotyping using two Hidden Markov model (HMM) algorithms, PennCNV and QuantiSNP, which call CNVs based on logR ratio and B allele frequency. Deletions and duplications greater than 10 kb were included. Common CNVs were excluded. Association testing was performed with 1 million permutations in PLINK. Significant CNVs were confirmed with digital droplet polymerase chain reaction (ddPCR). Whole genome sequencing was performed to determine insertion location and breakpoints. Results: Esotropia patients have similar rates and proportions of CNVs compared with controls but greater total length and average size of both deletions and duplications. Three recurrent rare duplications significantly (P = 1 × 10-6) increase the risk of esotropia: chromosome 2p11.2 (hg19, 2:87428677-87965359), spanning one long noncoding RNA (lncRNA) and two microRNAs (OR 14.16; 95% confidence interval [CI] 5.4-38.1); chromosome 4p15.2 (hg19, 4:25554332-25577184), spanning one lncRNA (OR 11.1; 95% CI 4.6-25.2); chromosome 10q11.22 (hg19, 10:47049547-47703870) spanning seven protein-coding genes, one lncRNA, and four pseudogenes (OR 8.96; 95% CI 5.4-14.9). Overall, 114 cases (7%) and only 28 controls (0.7%) had one of the three rare duplications. No case nor control had more than one of these three duplications. Conclusions: Rare CNVs are a source of genetic variation that contribute to the genetic risk for comitant esotropia, which is likely polygenic. Future research into the functional consequences of these recurrent duplications may shed light on the pathophysiology of esotropia.
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Variações do Número de Cópias de DNA/genética , Esotropia/genética , Predisposição Genética para Doença/genética , Estudos de Casos e Controles , Feminino , Duplicação Gênica/genética , Frequência do Gene/genética , Técnicas de Genotipagem , Humanos , Lactente , Masculino , Cadeias de Markov , Reação em Cadeia da Polimerase , Fatores de RiscoRESUMO
Intraocular injury by epinephrine auto-injector has been rarely reported. Toxic risk to the intraocular structures is suspected, but the evidence is inconclusive. We present the case of a 2-year-old girl who sustained an injury to her right eye by inadvertent epinephrine injection. Cataract surgery was performed to treat an increasingly opaque lens, and an intraocular lens was implanted. The visual outcome was good, with no retinal damage.
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Traumatismos Oculares , Extração de Catarata , Pré-Escolar , Epinefrina , Feminino , Humanos , Cristalino , Lentes IntraocularesRESUMO
Oculomotor neurons (CN3s) and trochlear neurons (CN4s) exhibit remarkable resistance to degenerative motor neuron diseases such as amyotrophic lateral sclerosis (ALS) when compared to spinal motor neurons (SMNs). The ability to isolate and culture primary mouse CN3s, CN4s, and SMNs would provide an approach to study mechanisms underlying this selective vulnerability. To date, most protocols use heterogeneous cell cultures, which can confound the interpretation of experimental outcomes. To minimize the problems associated with mixed-cell populations, pure cultures are indispensable. Here, the first protocol describes in detail how to efficiently purify and cultivate CN3s/CN4s alongside SMNs counterparts from the same embryos using embryonic day 11.5 (E11.5) IslMN:GFP transgenic mouse embryos. The protocol provides details on the tissue dissection and dissociation, FACS-based cell isolation, and in vitro cultivation of cells from CN3/CN4 and SMN nuclei. This protocol adds a novel in vitro CN3/CN4 culture system to existing protocols and simultaneously provides a pure species- and age-matched SMN culture for comparison. Analyses focusing on the morphological, cellular, molecular, and electrophysiological characteristics of motor neurons are feasible in this culture system. This protocol will enable research into the mechanisms that define motor neuron development, selective vulnerability, and disease.
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Embrião de Mamíferos/citologia , Proteínas de Fluorescência Verde/metabolismo , Proteínas com Homeodomínio LIM/fisiologia , Neurônios Motores/citologia , Nervo Oculomotor/citologia , Medula Espinal/citologia , Fatores de Transcrição/fisiologia , Nervo Troclear/citologia , Animais , Técnicas de Cultura de Células , Núcleo Celular/metabolismo , Embrião de Mamíferos/metabolismo , Camundongos , Camundongos Transgênicos , Neurônios Motores/metabolismo , Nervo Oculomotor/metabolismo , Medula Espinal/metabolismo , Nervo Troclear/metabolismoRESUMO
The somatotopic motor-neuron projections onto their cognate target muscles are essential for coordinated movement, but how that occurs for facial motor circuits, which have critical roles in respiratory and interactive behaviors, is poorly understood. We report extensive molecular heterogeneity in developing facial motor neurons in the mouse and identify markers of subnuclei and the motor pools innervating specific facial muscles. Facial subnuclei differentiate during migration to the ventral hindbrain, where neurons with progressively later birth dates-and evolutionarily more recent functions-settle in more-lateral positions. One subpopulation marker, ETV1, determines both positional and target muscle identity for neurons of the dorsolateral (DL) subnucleus. In Etv1 mutants, many markers of DL differentiation are lost, and individual motor pools project indifferently to their own and neighboring muscle targets. The resulting aberrant activation patterns are reminiscent of the facial synkinesis observed in humans after facial nerve injury.
Assuntos
Proteínas de Ligação a DNA/metabolismo , Músculos Faciais/embriologia , Músculos Faciais/inervação , Neurônios Motores/fisiologia , Fatores de Transcrição/metabolismo , Animais , Movimento Celular , Feminino , Fatores de Transcrição Forkhead/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Masculino , Camundongos Mutantes , Mutação/genética , Proteínas Repressoras/metabolismo , Transcrição GênicaRESUMO
Accurate eye movements are crucial for vision, but the development of the ocular motor system, especially the molecular pathways controlling axon guidance, has not been fully elucidated. This is partly due to technical limitations of traditional axon guidance assays. To identify additional axon guidance cues influencing the oculomotor nerve, an ex vivo slice assay to image the oculomotor nerve in real-time as it grows towards the eye was developed. E10.5 IslMN-GFP embryos are used to generate ex vivo slices by embedding them in agarose, slicing on a vibratome, then growing them in a microscope stage-top incubator with time-lapse photomicroscopy for 24-72 h. Control slices recapitulate the in vivo timing of outgrowth of axons from the nucleus to the orbit. Small molecule inhibitors or recombinant proteins can be added to the culture media to assess the role of different axon guidance pathways. This method has the advantages of maintaining more of the local microenvironment through which axons traverse, not axotomizing the growing axons, and assessing the axons at multiple points along their trajectory. It can also identify effects on specific subsets of axons. For example, inhibition of CXCR4 causes axons still within the midbrain to grow dorsally rather than ventrally, but axons that have already exited ventrally are not affected.
Assuntos
Músculos Oculomotores/metabolismo , Nervo Oculomotor/crescimento & desenvolvimento , Técnicas de Cultura de Órgãos/métodos , Imagem com Lapso de Tempo/métodos , Animais , Axônios , Axotomia , Meios de Cultura , Movimentos Oculares , Feminino , Proteínas de Fluorescência Verde , Camundongos , Camundongos Transgênicos , Músculos Oculomotores/embriologia , Músculos Oculomotores/inervação , Nervo Oculomotor/embriologia , Órbita/crescimento & desenvolvimento , Órbita/inervação , Gravidez , Receptores CXCR4/antagonistas & inibidoresRESUMO
Oculomotor synkinesis is the involuntary movement of the eyes or eyelids with a voluntary attempt at a different movement. The chemokine receptor CXCR4 and its ligand CXCL12 regulate oculomotor nerve development; mice with loss of either molecule have oculomotor synkinesis. In a consanguineous family with congenital ptosis and elevation of the ptotic eyelid with ipsilateral abduction, we identified a co-segregating homozygous missense variant (c.772G>A) in ACKR3, which encodes an atypical chemokine receptor that binds CXCL12 and functions as a scavenger receptor, regulating levels of CXCL12 available for CXCR4 signaling. The mutant protein (p.V258M) is expressed and traffics to the cell surface but has a lower binding affinity for CXCL12. Mice with loss of Ackr3 have variable phenotypes that include misrouting of the oculomotor and abducens nerves. All embryos show oculomotor nerve misrouting, ranging from complete misprojection in the midbrain, to aberrant peripheral branching, to a thin nerve, which aberrantly innervates the lateral rectus (as seen in Duane syndrome). The abducens nerve phenotype ranges from complete absence, to aberrant projections within the orbit, to a normal trajectory. Loss of ACKR3 in the midbrain leads to downregulation of CXCR4 protein, consistent with reports that excess CXCL12 causes ligand-induced degradation of CXCR4. Correspondingly, excess CXCL12 applied to ex vivo oculomotor slices causes axon misrouting, similar to inhibition of CXCR4. Thus, ACKR3, through its regulation of CXCL12 levels, is an important regulator of axon guidance in the oculomotor system; complete loss causes oculomotor synkinesis in mice, while reduced function causes oculomotor synkinesis in humans.