OMIA Database

Overview

OMIA (Online Mendelian Inheritance in Animals) is a veterinary genetic disease database maintained by the University of Sydney. It catalogs inherited disorders, morphological traits, and genetic variants across 300+ animal species, with extensive data on companion animals (dogs, cats), livestock (cattle, horses, sheep), and model organisms. OMIA is the animal medicine equivalent of OMIM (Online Mendelian Inheritance in Man).

When to Use

• User searches for inherited diseases in a specific breed or species (e.g., hip dysplasia in Golden Retrievers)
• User identifies genetic basis for clinical phenotype (mutation + gene + inheritance pattern)
• User researches breed predispositions for preventive medicine or breeding programs
• User maps veterinary genetic variants to human orthologous diseases (translational oncology)
• User looks up Mendelian inheritance patterns, carrier frequencies, diagnostic tests
• Keywords: OMIA, inherited disease, genetic, Mendelian, breed predisposition, mutation, gene, carrier, MDR1

What is OMIA?

Database Contents:

• 6,000+ inherited disorders and traits across 300+ species
• 15,000+ genetic loci/genes documented
• Emphasis on companion animals (dogs, cats, rabbits) and livestock
• Cross-referenced with OMIM, GenBank, UniProt for translational research

Regulatory Scope:

• Non-profit, university-maintained (University of Sydney)
• Peer-reviewed disease/trait entries (veterinarians, geneticists)
• Continuously updated as new genetic discoveries published
• Free public access: https://www.omia.org

Typical Entry Includes:

• Disease/trait name and synonyms
• Affected species, breeds, ethnic groups
• Gene(s) involved and chromosomal location
• Mutation(s) identified
• Inheritance pattern (autosomal dominant/recessive, X-linked, multifactorial)
• Phenotype description
• Diagnostic test availability
• References (peer-reviewed publications)
• Frequency/prevalence in breed(s)

Key Veterinary Conditions in OMIA

Genetic Disease Examples (Canine):

Genetic Disease Examples (Feline):

Livestock Examples:

Accessing OMIA

Web Interface: https://www.omia.org

Search Functions:

1. By Disease Name:

   • Enter "hip dysplasia" → Returns all species with HipDys, filter by breed
   • Enter "von Willebrand" → Returns type 1, 2, 3 (multiple loci)

2. By Breed:

   • Select "Labrador Retriever" → Lists all documented inherited disorders in breed
   • Shows genetic basis, carrier testing availability, prevalence

3. By Gene:

   • Enter "MDR1" → Shows all species/breeds affected by MDR1 variants
   • Returns all conditions linked to that gene (drug sensitivities, etc.)

4. By Chromosome Location:

   • Search "canine chromosome 5" → Lists all genes/disorders mapped to that chromosome

5. By Species:

   • Select "Felis catus" → Display all inherited diseases in cats
   • Comprehensive list with prevalence in common breeds

OMIA Entry Structure

Typical OMIA Record Includes:

Title: Hip Dysplasia, Canine
Synonym: Canine Hip Dysplasia (CHD), Hip Dysplasia in Dogs

Affected Species: Canis familiaris

Genes:
  FN (Fibronectin): Complex/multifactorial
  Evidence: GWAS studies, candidate gene association

Inheritance: Multifactorial (polygenic + environmental)
  - Autosomal inheritance
  - Influenced by body size, growth rate, exercise
  - Penetrance variable

Phenotype:
  - Clinical: Hind limb lameness, pain, degenerative joint disease
  - Radiographic: Femoral head subluxation, shallow acetabulum
  - Age of onset: 6 months to 5+ years

Breed Predispositions:
  - Higher risk: German Shepherd, Golden Retriever, Labrador
  - Lower risk: Greyhound, Dachshund, small toy breeds
  - Prevalence: 5-10% in high-risk breeds (radiographic screening)

Diagnostic Tests:
  - Radiographic assessment (PennHIP, Orthopaedic Foundation for Animals)
  - Genetic testing: Not available (complex trait)
  - Parentage verification: Recommended for breeding programs

Prevention:
  - Selective breeding (screen parents radiographically)
  - Weight management
  - Exercise moderation in juvenile period
  - Environmental factors

References:
  - 15-30 peer-reviewed publications
  - Links to PubMed, GenBank accessions

Inheritance Pattern Descriptions

Autosomal Dominant:

• One mutant allele sufficient for phenotype
• Affected individual has ≥50% affected offspring (if heterozygous)
• Example: von Willebrand Disease type 1 (variability in expression)
• Carriers: Usually symptomatic (unless variably penetrant)

Autosomal Recessive:

• Two mutant alleles required for phenotype
• Affected individual: homozygous (aa)
• Carriers: heterozygous (Aa) - unaffected but can transmit
• Affected offspring from two carriers: 25% (a/a), 50% carriers (A/a), 25% normal (A/A)
• Example: MDR1 mutation in collies; colorblindness

X-Linked Recessive:

• Mutation on X chromosome
• Males (XaY) affected; females (XAXa) carriers usually unaffected
• Female carriers can have 50% affected male offspring
• Example: Hemophilia B (F9 gene)

Multifactorial (Complex Trait):

• Multiple genes + environmental factors
• No simple Mendelian inheritance
• Siblings of affected animal have increased but not predictable risk
• Example: Hip dysplasia, elbow dysplasia, most cancer predispositions
• Polygenic risk scores being developed

Mitochondrial:

• Rare; inheritance through maternal cytoplasm
• All offspring of affected mother likely affected
• Father never transmits
• Example: Some neurologic conditions

Breed Predisposition Analysis

OMIA Approach:

1. Select breed (e.g., Collie)
2. OMIA lists all documented genetic diseases
3. Prevalence/carrier frequency provided if known
4. Genetic basis explained

Collie Breed Example (Partial List):

• MDR1 mutation: ~50-70% carriers; 5-10% homozygous affected (varies by region)
• Collie Eye Anomaly: Autosomal recessive; ~15-25% carriers
• Microphthalmia: Rare; autosomal recessive
• Smooth/Rough coat: Autosomal dominant (phenotypic, not disease)

Breeding Program Integration:

• Veterinarians counsel clients on inherited disease risks
• Recommend genetic testing before breeding
• OMIA provides test recommendations (OFA, Orthopedic Foundation for Animals)
• Breeding decisions: avoid mating two carriers of recessive disease

Diagnostic Test Information

OMIA Lists:

• Where testing is available (genetic testing labs, universities, breed clubs)
• Test method (DNA sequencing, SNP panel, enzyme assay)
• Cost range (typically $50-300)
• Turnaround time (7-14 days typical)
• Interpretation (affected, carrier, clear)

Example: MDR1 Testing

• Gene: MDR1 (P-glycoprotein)
• Test Method: DNA PCR, mutation-specific assay
• Labs: VetGen, UC Davis, Mars Petcare
• Cost: ~$75-150
• Result: Wild-type/normal, heterozygous/carrier, homozygous/affected
• Clinical Use: Guide ivermectin/avermectin dosing or avoidance

Cross-Reference with OMIM (Human Diseases)

Translational Value: OMIA links veterinary genetic diseases to human orthologous conditions via OMIM IDs.

Example: Canine Hemophilia B → Human Hemophilia B

• Canine: F9 gene mutation, X-linked; bleeding disorder
• Human: Same F9 gene mutation; hemophilia B/Christmas disease
• Translational Research: Dogs with naturally occurring F9 mutations used in gene therapy trials for human hemophilia
• Phenotype Monitoring: Similar coagulation cascade, bone/joint hemorrhage complications

Oncology Example: Canine Osteosarcoma

• Canine genetic predispositions (SV40, TP53, BRCA1/BRCA2)
• Homologous to human osteosarcoma (same mutations associated)
• Translational: Canine tumors provide model for human pediatric osteosarcoma therapy

Advantage: Veterinary research informs human genomic medicine; human discoveries guide animal breeding/treatment.

OMIA-Based Clinical Workflows

Workflow 1: Preventive Genetic Screening

1. Patient: 8-month-old Labrador Retriever
2. Breed enters OMIA → retrieve predispositions
3. High-risk conditions identified:
   - Hip dysplasia (multifactorial)
   - Elbow dysplasia (multifactorial)
   - Exercise-Induced Collapse (EIC, autosomal recessive)
   - Progressive Retinal Atrophy (PRA, multiple loci)
4. Veterinarian recommends:
   - Radiographic screening (hips/elbows at 2 years)
   - Genetic testing for EIC, PRA (DNA test $50-100 each)
   - Weight management + controlled exercise until skeletal maturity
5. Client counseling: If breeding planned, genetic tests required before mating

Workflow 2: Unexplained Clinical Sign

1. Patient: 3-year-old male Collie, seizures + progressive neurologic decline
2. Differential: Search OMIA for "Collie + neurologic"
3. OMIA findings:
   - Collie Eye Anomaly (autosomal recessive) → not neurologic
   - Ceroid Lipofuscinosis (NCL, autosomal recessive) → matches (neurologic, progressive)
   - Other: Epilepsy (genetic + idiopathic)
4. Diagnostic approach: Genetic test for NCL mutation (DNA test)
5. If positive: Genetic counseling, management strategy, breeding advice

Workflow 3: Breed Club Genetic Health Program

1. Breed club curator: Compile genetic disease prevalence in breed
2. Use OMIA to identify priority conditions (high prevalence, severity)
3. Establish testing recommendations (mandatory for breeding):
   - Eye examination (CERF - Canine Eye Registration Foundation)
   - Hip/elbow radiographs (OFA)
   - Genetic tests for recessive conditions (DNA labs)
4. Breeding registry: Track genetic test results, accumulate data
5. Long-term: Monitor frequency trends, inform breeding practices

Limitations

• Ascertainment Bias: Documented disorders are often those affecting popular breeds; rare breed diseases underrepresented
• Incomplete Penetrance: Some dominant conditions show variable expression (carriers may be asymptomatic)
• Variable Prevalence: Frequency data may be outdated or based on limited studies
• Multifactorial Diseases: Hip dysplasia, cancer predispositions are difficult to model genetically; simple Mendelian predictions fail
• Species Variation: Small animal (dog/cat) data extensive; exotic/wildlife sparse
• International Variation: Prevalence data often US-centric; European breeding practices may differ

Sources

• OMIA Database: https://www.omia.org
• OMIA Advanced Search: https://www.omia.org/search
• OMIM (Human Diseases): https://www.omim.org (cross-reference)
• OFA (Orthopedic Foundation for Animals): https://www.ofa.org (screening databases)
• Canine Inherited Disorders Database: https://www.cidc.iastate.edu/ (Iowa State)
• Feline Genetics Laboratory: UC Davis School of Veterinary Medicine
• PubMed: Cross-referenced from OMIA entries

Advanced Integration

VetClaw SDK may provide OMIA query wrappers for automated breed risk stratification. Consult /sessions/charming-practical-mayer/mnt/OpenVet/vetclaw/vetclaw/sdk/ for Python/TypeScript client examples integrating OMIA breed predisposition data.