The Human Phenotype Ontology in 2021 Köhler, Sebastian; Gargano, Michael; Matentzoglu, Nicolas ...
Nucleic acids research,
01/2021, Volume:
49, Issue:
D1
Journal Article
Peer reviewed
Open access
Abstract
The Human Phenotype Ontology (HPO, https://hpo.jax.org) was launched in 2008 to provide a comprehensive logical standard to describe and computationally analyze phenotypic abnormalities ...found in human disease. The HPO is now a worldwide standard for phenotype exchange. The HPO has grown steadily since its inception due to considerable contributions from clinical experts and researchers from a diverse range of disciplines. Here, we present recent major extensions of the HPO for neurology, nephrology, immunology, pulmonology, newborn screening, and other areas. For example, the seizure subontology now reflects the International League Against Epilepsy (ILAE) guidelines and these enhancements have already shown clinical validity. We present new efforts to harmonize computational definitions of phenotypic abnormalities across the HPO and multiple phenotype ontologies used for animal models of disease. These efforts will benefit software such as Exomiser by improving the accuracy and scope of cross-species phenotype matching. The computational modeling strategy used by the HPO to define disease entities and phenotypic features and distinguish between them is explained in detail.We also report on recent efforts to translate the HPO into indigenous languages. Finally, we summarize recent advances in the use of HPO in electronic health record systems.
Objective
Voltage‐gated sodium (Na+) channels underlie action potential generation and propagation and hence are central to the regulation of excitability in the nervous system. Mutations in the ...genes SCN1A, SCN2A, and SCN8A, encoding the Na+ channel pore‐forming (α) subunits Nav1.1, 1.2, and 1.6, respectively, and SCN1B, encoding the accessory subunit β1, are established causes of genetic epilepsies. SCN3A, encoding Nav1.3, is known to be highly expressed in brain, but has not previously been linked to early infantile epileptic encephalopathy. Here, we describe a cohort of 4 patients with epileptic encephalopathy and heterozygous de novo missense variants in SCN3A (p.Ile875Thr in 2 cases, p.Pro1333Leu, and p.Val1769Ala).
Methods
All patients presented with treatment‐resistant epilepsy in the first year of life, severe to profound intellectual disability, and in 2 cases (both with the variant p.Ile875Thr), diffuse polymicrogyria.
Results
Electrophysiological recordings of mutant channels revealed prominent gain of channel function, with a markedly increased amplitude of the slowly inactivating current component, and for 2 of 3 mutants (p.Ile875Thr and p.Pro1333Leu), a leftward shift in the voltage dependence of activation to more hyperpolarized potentials. Gain of function was not observed for Nav1.3 variants known or presumed to be inherited (p.Arg1642Cys and p.Lys1799Gln). The antiseizure medications phenytoin and lacosamide selectively blocked slowly inactivating over transient current in wild‐type and mutant Nav1.3 channels.
Interpretation
These findings establish SCN3A as a new gene for infantile epileptic encephalopathy and suggest a potential pharmacologic intervention. These findings also reinforce the role of Nav1.3 as an important regulator of neuronal excitability in the developing brain, while providing additional insight into mechanisms of slow inactivation of Nav1.3. Ann Neurol 2018;83:703–717
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Abstract
In biology and biomedicine, relating phenotypic outcomes with genetic variation and environmental factors remains a challenge: patient phenotypes may not match known diseases, candidate ...variants may be in genes that haven’t been characterized, research organisms may not recapitulate human or veterinary diseases, environmental factors affecting disease outcomes are unknown or undocumented, and many resources must be queried to find potentially significant phenotypic associations. The Monarch Initiative (https://monarchinitiative.org) integrates information on genes, variants, genotypes, phenotypes and diseases in a variety of species, and allows powerful ontology-based search. We develop many widely adopted ontologies that together enable sophisticated computational analysis, mechanistic discovery and diagnostics of Mendelian diseases. Our algorithms and tools are widely used to identify animal models of human disease through phenotypic similarity, for differential diagnostics and to facilitate translational research. Launched in 2015, Monarch has grown with regards to data (new organisms, more sources, better modeling); new API and standards; ontologies (new Mondo unified disease ontology, improvements to ontologies such as HPO and uPheno); user interface (a redesigned website); and community development. Monarch data, algorithms and tools are being used and extended by resources such as GA4GH and NCATS Translator, among others, to aid mechanistic discovery and diagnostics.
The developmental and epileptic encephalopathies (DEEs) are heterogeneous disorders with a strong genetic contribution, but the underlying genetic etiology remains unknown in a significant proportion ...of individuals. To explore whether statistical support for genetic etiologies can be generated on the basis of phenotypic features, we analyzed whole-exome sequencing data and phenotypic similarities by using Human Phenotype Ontology (HPO) in 314 individuals with DEEs. We identified a de novo c.508C>T (p.Arg170Trp) variant in AP2M1 in two individuals with a phenotypic similarity that was higher than expected by chance (p = 0.003) and a phenotype related to epilepsy with myoclonic-atonic seizures. We subsequently found the same de novo variant in two individuals with neurodevelopmental disorders and generalized epilepsy in a cohort of 2,310 individuals who underwent diagnostic whole-exome sequencing. AP2M1 encodes the μ-subunit of the adaptor protein complex 2 (AP-2), which is involved in clathrin-mediated endocytosis (CME) and synaptic vesicle recycling. Modeling of protein dynamics indicated that the p.Arg170Trp variant impairs the conformational activation and thermodynamic entropy of the AP-2 complex. Functional complementation of both the μ-subunit carrying the p.Arg170Trp variant in human cells and astrocytes derived from AP-2μ conditional knockout mice revealed a significant impairment of CME of transferrin. In contrast, stability, expression levels, membrane recruitment, and localization were not impaired, suggesting a functional alteration of the AP-2 complex as the underlying disease mechanism. We establish a recurrent pathogenic variant in AP2M1 as a cause of DEEs with distinct phenotypic features, and we implicate dysfunction of the early steps of endocytosis as a disease mechanism in epilepsy.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Objective
Pathogenic variants in SCN3A, encoding the voltage‐gated sodium channel subunit Nav1.3, cause severe childhood onset epilepsy and malformation of cortical development. Here, we define the ...spectrum of clinical, genetic, and neuroimaging features of SCN3A‐related neurodevelopmental disorder.
Methods
Patients were ascertained via an international collaborative network. We compared sodium channels containing wild‐type versus variant Nav1.3 subunits coexpressed with β1 and β2 subunits using whole‐cell voltage clamp electrophysiological recordings in a heterologous mammalian system (HEK‐293T cells).
Results
Of 22 patients with pathogenic SCN3A variants, most had treatment‐resistant epilepsy beginning in the first year of life (16/21, 76%; median onset, 2 weeks), with severe or profound developmental delay (15/20, 75%). Many, but not all (15/19, 79%), exhibited malformations of cortical development. Pathogenic variants clustered in transmembrane segments 4 to 6 of domains II to IV. Most pathogenic missense variants tested (10/11, 91%) displayed gain of channel function, with increased persistent current and/or a leftward shift in the voltage dependence of activation, and all variants associated with malformation of cortical development exhibited gain of channel function. One variant (p.Ile1468Arg) exhibited mixed effects, with gain and partial loss of function. Two variants demonstrated loss of channel function.
Interpretation
Our study defines SCN3A‐related neurodevelopmental disorder along a spectrum of severity, but typically including epilepsy and severe or profound developmental delay/intellectual disability. Malformations of cortical development are a characteristic feature of this unusual channelopathy syndrome, present in >75% of affected individuals. Gain of function at the channel level in developing neurons is likely an important mechanism of disease pathogenesis. ANN NEUROL 2020;88:348–362
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
OBJECTIVETo assess the rapid implementation of child neurology telehealth outpatient care with the onset of the coronavirus disease 2019 (COVID-19) pandemic in March 2020.
METHODSThis was a cohort ...study with retrospective comparison of 14,780 in-person encounters and 2,589 telehealth encounters, including 2,093 audio-video telemedicine and 496 scheduled telephone encounters, between October 1, 2019 and April 24, 2020. We compared in-person and telehealth encounters for patient demographics and diagnoses. For audio-video telemedicine encounters, we analyzed questionnaire responses addressing provider experience, follow-up plans, technical quality, need for in-person assessment, and parent/caregiver satisfaction. We performed manual reviews of encounters flagged as concerning by providers.
RESULTSThere were no differences in patient age and major ICD-10 codes before and after transition. Clinicians considered telemedicine satisfactory in 93% (1,200 of 1,286) of encounters and suggested telemedicine as a component for follow-up care in 89% (1,144 of 1,286) of encounters. Technical challenges were reported in 40% (519 of 1,314) of encounters. In-person assessment was considered warranted after 5% (65 of 1,285) of encounters. Patients/caregivers indicated interest in telemedicine for future care in 86% (187 of 217) of encounters. Participation in telemedicine encounters compared to telephone encounters was less frequent among patients in racial or ethnic minority groups.
CONCLUSIONSWe effectively converted most of our outpatient care to telehealth encounters, including mostly audio-video telemedicine encounters. Providers rated the vast majority of telemedicine encounters to be satisfactory, and only a small proportion of encounters required short-term in-person follow-up. These findings suggest that telemedicine is feasible and effective for a large proportion of child neurology care. Additional strategies are needed to ensure equitable telemedicine use.
The Human Phenotype Ontology (HPO) project, available at http://www.human-phenotype-ontology.org, provides a structured, comprehensive and well-defined set of 10,088 classes (terms) describing human ...phenotypic abnormalities and 13,326 subclass relations between the HPO classes. In addition we have developed logical definitions for 46% of all HPO classes using terms from ontologies for anatomy, cell types, function, embryology, pathology and other domains. This allows interoperability with several resources, especially those containing phenotype information on model organisms such as mouse and zebrafish. Here we describe the updated HPO database, which provides annotations of 7,278 human hereditary syndromes listed in OMIM, Orphanet and DECIPHER to classes of the HPO. Various meta-attributes such as frequency, references and negations are associated with each annotation. Several large-scale projects worldwide utilize the HPO for describing phenotype information in their datasets. We have therefore generated equivalence mappings to other phenotype vocabularies such as LDDB, Orphanet, MedDRA, UMLS and phenoDB, allowing integration of existing datasets and interoperability with multiple biomedical resources. We have created various ways to access the HPO database content using flat files, a MySQL database, and Web-based tools. All data and documentation on the HPO project can be found online.
Mitochondrial disorders causing neurodegeneration in childhood are genetically heterogeneous, and the underlying genetic etiology remains unknown in many affected individuals. We identified biallelic ...variants in PMPCB in individuals of four families including one family with two affected siblings with neurodegeneration and cerebellar atrophy. PMPCB encodes the catalytic subunit of the essential mitochondrial processing protease (MPP), which is required for maturation of the majority of mitochondrial precursor proteins. Mitochondria isolated from two fibroblast cell lines and induced pluripotent stem cells derived from one affected individual and differentiated neuroepithelial stem cells showed reduced PMPCB levels and accumulation of the processing intermediate of frataxin, a sensitive substrate for MPP dysfunction. Introduction of the identified PMPCB variants into the homologous S. cerevisiae Mas1 protein resulted in a severe growth and MPP processing defect leading to the accumulation of mitochondrial precursor proteins and early impairment of the biogenesis of iron-sulfur clusters, which are indispensable for a broad range of crucial cellular functions. Analysis of biopsy materials of an affected individual revealed changes and decreased activity in iron-sulfur cluster-containing respiratory chain complexes and dysfunction of mitochondrial and cytosolic Fe-S cluster-dependent enzymes. We conclude that biallelic mutations in PMPCB cause defects in MPP proteolytic activity leading to dysregulation of iron-sulfur cluster biogenesis and triggering a complex neurological phenotype of neurodegeneration in early childhood.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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