Illnesses You Inherit From Your Mother

Health Conditions That Can Run Down Your Mother's Side

When several relatives on the same side of a family develop similar conditions, genetics may be one part of the explanation. But inherited risk and actually developing a disease are two very different things.

Breast And Ovarian Cancer Risk Can Run In Families

Certain inherited variants, including harmful changes in BRCA1 and BRCA2, can substantially increase the risk of breast and ovarian cancer.

These variants aren't exclusively inherited from mothers — either parent can pass them on.

However, a mother's family history can provide important clues. Multiple relatives with breast or ovarian cancer, cancers occurring unusually young, male breast cancer, or certain combinations of cancers can be reasons to discuss family history with a healthcare professional.

Genetic counselling can help determine whether testing may be appropriate.

Type 2 Diabetes Can Have A Family Connection

If your mother has type 2 diabetes, your own risk may be higher — but that doesn't mean you've directly "inherited diabetes."

Many genetic variants can influence susceptibility, while weight, physical activity, age and other environmental and lifestyle factors also matter.

That's why two people with similar family histories can have very different outcomes.

Knowing that diabetes appears repeatedly in your family can still be useful because it gives you and your healthcare provider more information when assessing your overall risk.

Some Heart Problems Can Be Inherited

High blood pressure and common forms of cardiovascular disease are influenced by a mixture of genetics, lifestyle and environment.

But some specific heart conditions have much stronger genetic components.

Inherited cardiomyopathies and certain heart-rhythm disorders, for example, can occur within families.

Again, these aren't necessarily "from your mother." They may be inherited from either side.

A family history of unexplained sudden death, inherited heart disease or serious heart problems at unusually young ages deserves particular attention.

The DNA You Really Do Inherit From Your Mother

There's one fascinating genetic exception that makes maternal inheritance particularly unusual.

Almost all of your mitochondrial DNA normally comes from your mother.

Mitochondrial Conditions Follow A Different Pattern

Mitochondria are tiny structures inside cells that help produce energy.

They contain their own DNA, known as mitochondrial DNA or mtDNA.

Unlike most of your DNA, mtDNA is generally inherited through the egg. That means mitochondrial genetic variants are typically passed from a mother to her children.

Some harmful mitochondrial DNA variants can cause mitochondrial diseases affecting organs and tissues with high energy requirements.

Symptoms and severity can vary considerably depending on the particular condition.

Both Sons And Daughters Can Be Affected

A mother carrying a disease-causing mitochondrial DNA variant can pass it to sons and daughters.

But there is an unusual twist.

A man with a mitochondrial DNA condition generally doesn't pass his mitochondrial DNA to his children.

A woman potentially can.

This makes mitochondrial inheritance very different from the inheritance patterns most people learn about at school.

The Same Condition Can Affect Relatives Differently

Mitochondrial genetics can become complicated.

Different cells can contain different proportions of altered and unaffected mitochondrial DNA, a phenomenon known as heteroplasmy.

That can help explain why people within the same family may experience very different symptoms or severity.

If a mitochondrial condition is suspected within a family, specialist genetic assessment is much more useful than trying to predict someone's risk from a family tree alone.

Conditions Mothers Can Carry Without Realising

Some genetic conditions follow an X-linked inheritance pattern.

This can create situations where a mother has few or no symptoms but carries a genetic variant that can affect her children.

Red-Green Colour Vision Deficiency Can Run This Way

The common inherited forms of red-green colour vision deficiency are usually X-linked.

Because males generally have one X chromosome, inheriting an affected version of the relevant gene can result in colour vision deficiency.

Females generally have two X chromosomes, so an unaffected copy can sometimes compensate for an affected one.

This is why red-green colour vision deficiency is considerably more common in males.

A mother can therefore carry a relevant variant without necessarily having the same degree of colour vision difficulty herself.

Haemophilia Has A Famous Inheritance Pattern

Haemophilia A and haemophilia B are commonly X-linked inherited bleeding disorders.

A woman carrying a disease-causing variant can pass the affected X chromosome to her children.

Sons who inherit it may develop haemophilia, while daughters who inherit it may be carriers and can sometimes have bleeding symptoms themselves.

Not every case is inherited — new genetic changes can also occur.

Genetic testing and specialist assessment are needed to determine an individual's actual status.

Duchenne Muscular Dystrophy Can Also Be X-Linked

Duchenne muscular dystrophy is another well-known X-linked genetic condition.

It primarily affects boys and causes progressive muscle weakness.

A mother carrying a disease-causing DMD variant can pass it to her children, although some cases arise from a new genetic variant rather than being inherited from a parent.

Female carriers can also sometimes experience health effects themselves, including muscle or heart problems, so "carrier" doesn't necessarily mean completely unaffected.

Family History From Your Mother You Shouldn't Ignore

The most useful lesson isn't to assume that particular illnesses automatically come from your mother.

It's to know your family history on both sides.

Look For Patterns Rather Than One Relative

One relative developing a common illness late in life doesn't necessarily indicate a strong inherited syndrome.

Patterns can be more informative.

Examples worth mentioning to a healthcare professional can include multiple relatives developing the same or related cancers, unusually early heart disease, unexplained sudden deaths, known genetic disorders, or illnesses repeatedly appearing across generations.

Write down which relatives were affected and, if possible, approximately how old they were when diagnosed.

Your Father's Family History Matters Just As Much

This is the part people sometimes misunderstand.

Most of your genes aren't divided into "mum's diseases" and "dad's diseases."

For the majority of inherited conditions and genetic risk factors, relevant variants can come from either parent.

A harmful BRCA variant inherited from your father, for example, still matters.

So don't ignore half of your family tree simply because a condition is commonly discussed in relation to women.

Inherited Risk Doesn't Mean You're Destined To Get It

Genes can influence risk without determining your future.

Some genetic variants have powerful effects, while others only slightly alter the likelihood of developing a condition. Lifestyle, environment, age and chance can also play important roles.

If your family has a striking pattern of a particular disease, don't try to diagnose your genetic risk yourself.

Discuss the history with a healthcare professional or genetic counsellor.

Because the most important thing to understand about an illness that "runs in the family" is this:

Inheriting a genetic risk is not necessarily the same as inheriting the disease.