This page contains affiliate links. We may earn a commission if you purchase through them, at no extra cost to you. As an affiliate we earn from qualifying purchases via AWIN and CJ.

All Genetic Conditions A–Z

376 conditions covered. Click any condition to see its heritability verdict, inheritance pattern, and key genes.

Have a family history of one of these? Try our Family History Risk Checker →

Understanding Inheritance Patterns

Every condition below carries a heritability verdict — YES, PARTIAL, COMPLEX, or NO — describing how strongly genetics drives it. But "genetic" isn't one thing. A condition can run in families through several distinct biological mechanisms, or it can arise from a mutation that neither parent carried at all. Knowing which pattern applies to a condition changes what your own family history actually tells you about your risk, which is why we tag each condition's specific inheritance pattern alongside its verdict, not just a flat label.

Autosomal Dominant

A single altered copy of a gene, inherited from just one parent, is enough to cause the condition. A parent who carries the variant has roughly a 50% chance of passing it to each child, and the condition often appears in every generation. Several hereditary cancer syndromes in this directory, linked to genes like BRCA1 and BRCA2, follow this pattern.

Autosomal Recessive

Both copies of a gene — one inherited from each parent — must carry the altered version for the condition to appear. Parents who each carry a single copy ("carriers") are usually unaffected themselves, but have roughly a 25% chance of an affected child with each pregnancy if both are carriers.

X-Linked

The altered gene sits on the X chromosome. Because males have only one X chromosome, they are often more frequently or more severely affected than females, who carry a second X copy that can offset the variant. Inheritance risk depends on whether the mother or the father carries the altered gene.

Chromosomal

Caused by a change in the number or structure of whole chromosomes — an extra copy, a missing segment, or a rearrangement — rather than a single gene mutation. Down syndrome (trisomy 21) is the best-known example.

Inherited vs. Acquired (De Novo) Mutations

Not every genetic condition is passed down from a parent. An inherited mutation is already present in a parent's egg or sperm cell and is transmitted to a child at conception — it typically runs across generations and shows up in family history. An acquired (or de novo) mutation arises spontaneously in a single person, either very early in embryonic development or later in life within specific cells — as is the case for most cancers — and is not present in either parent's DNA. A de novo mutation can still be passed on to that person's own children, even though they didn't inherit it themselves. This is exactly why family history is a strong but imperfect signal: some conditions with a clear genetic cause show no prior pattern in the family at all.

You'll also see conditions in this directory tagged multifactorial or polygenic rather than one of the four classic patterns above. These arise from the combined, small-effect contribution of many genes interacting with lifestyle and environment — common in conditions such as type 2 diabetes or coronary artery disease — so no single inheritance rule applies cleanly. A smaller number are tagged mitochondrial (passed down through the mother's mitochondrial DNA only) or sporadic (occurring largely by chance, without a strong inherited component).

For deeper reading on how inheritance actually works, see the National Human Genome Research Institute's Talking Glossary of Genomic and Genetic Terms, the CDC's Genomics and Health overview, the NIH's Genetic and Rare Diseases Information Center (GARD), and MedlinePlus Genetics on inheriting a genetic condition.

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

R

S

T

U

V

W

X

US readers: Already know your genetic risk? HealthLabs lets you order blood biomarker tests without a doctor's referral — 4,000+ tests, no insurance needed, results in 1–3 business days.

CircleDNA — Premium DNA Test

The world's most comprehensive at-home DNA test. 500+ personalised reports across cancer risk, heart health, diet, fitness, medication response, and family planning — trusted by 500,000+ people worldwide.

  • Results delivered in 18 days
  • Includes genetic counsellor access
  • Covers 500+ health & wellness reports
Get your full genetic profile →
DNA Testing

Know for Certain — Certified DNA Results in 3–5 Days

Understanding whether a condition runs in your family sometimes means confirming biological relationships. Paternity Lab provides court-admissible and personal-use DNA tests — AABB-accredited, with 99.99% accuracy.

  • Results in 3–5 business days
  • Court-admissible legal testing available
  • Discreet home collection kit included
Order a certified DNA test →
Identity Protection

Your genetic data is the most sensitive personal information you'll ever share online. In 2023 alone, millions of DNA test users had their data exposed in breaches. SmartCredit monitors for data breaches and removes your personal information from the web — try it for $1 for 7 days.