Estimate penetrance f = affected carriers / total carriers with nonpenetrance, plus a severe/moderate/mild expressivity breakdown among affected carriers. Derived from Wright, Griffiths, OMIM, StatPearls. Educational use only.
Execution
Run this tool
Fill in the form, run the tool, and review the result in one place.
Samples
Examples that match this tool
Related
Continue with connected tools and hubs
Result
Ready for a run
Run the tool to preview files, text, structured data, or streamed output here.
Tool usage guide
Learn when to use this tool, what it supports, and how real users apply it.
Key facts
Category
Education
Input types
number
Output type
json
Sample coverage
4
API ready
Yes
Overview
Calculate gene penetrance from affected and total genotype carrier counts, then summarize severe, moderate, and mild expressivity among affected carriers. The results are provided for educational use only.
When to use
Estimate complete or incomplete penetrance in a genetics exercise or study dataset.
Compare phenotype severity among carriers who express a trait.
Demonstrate the difference between penetrance and variable expressivity.
How it works
1Enter the total number of genotype carriers and the number who show the phenotype.
2Enter the affected carriers classified as severe and mild; moderate cases are calculated as the remaining affected carriers.
3The calculator divides affected carriers by total carriers to find penetrance and calculates nonpenetrance as 1 minus penetrance.
4It returns the penetrance, nonpenetrance, and expressivity proportions in JSON, rounded to the selected number of decimal places.
Use cases
Calculate penetrance and nonpenetrance from observed carrier counts.
Summarize severe, moderate, and mild phenotype expression in an affected group.
Create worked examples for Mendelian genetics and genotype-phenotype lessons.
Examples
1. Incomplete penetrance in 40 carriers
Genetics student
Background
A class dataset contains 40 genotype carriers, of whom 32 show the phenotype. Among the affected carriers, 8 have severe expression and 12 have mild expression.
Problem
Calculate penetrance, nonpenetrance, and the severity distribution among affected carriers.
How to use
Enter 40 total carriers, 32 affected carriers, 8 severe cases, 12 mild cases, and 4 decimal places.
Total carriers: 40; affected carriers: 32; severe cases: 8; mild cases: 12; decimal places: 4.
Outcome
Penetrance is 80% and nonpenetrance is 20%. Expressivity among affected carriers is 25% severe, 37.5% moderate, and 37.5% mild.
2. Complete penetrance with variable expressivity
Biology instructor
Background
An instructional example includes 50 genotype carriers, and all 50 show the phenotype. Five affected carriers are severe and 30 are mild.
Problem
Show that complete penetrance can occur alongside different levels of phenotype severity.
How to use
FAQ
What is gene penetrance?
Penetrance is the proportion of genotype carriers who show the associated phenotype.
How is nonpenetrance calculated?
Nonpenetrance equals 1 minus penetrance, or unaffected carriers divided by total carriers.
How are moderate expression cases determined?
Moderate cases are the affected carriers remaining after severe and mild cases are subtracted.
What is the difference between penetrance and expressivity?
Penetrance indicates whether a phenotype appears, while expressivity describes its severity among affected carriers.
Can this calculator provide medical or genetic counseling?
No. It is an educational calculator and does not replace clinical assessment or genetic counseling.