Familial hypercholesterolaemia is an inherited condition in which variants in certain genes affect the liver’s ability to process low-density lipoprotein cholesterol, which can lead to premature atherosclerotic cardiovascular diseases.

Huntington disease is a progressive neurodegenerative condition that causes motor, cognitive and psychiatric decline. It is inherited, and affected individuals have a 1 in 2 (50%) chance of passing it on to their children.

Hereditary haemochromatosis is characterised by an excess of iron in particular organs in the body. It affects both sexes equally, though women often present later than men. It is caused by pathogenic variants in the HFE gene.

Alpha-1 antitrypsin deficiency is an inherited condition that can increase an individual’s chance of developing lung and liver diseases.

When an individual has been diagnosed with monogenic diabetes, genomic testing should be offered to their first-degree relatives. Genomic counselling is required prior to testing for any family members who are not known to have diabetes.

Around 5%–10% of cancers are caused by pathogenic variants in a cancer susceptibility gene. The inheritance of multiple lower-risk variants also increases cancer risk. Identifying individuals who are at increased risk can enable targeted screening, prevention and early diagnosis.

Alpha-1 antitrypsin deficiency is a genetic condition that can predispose an individual to lung and liver diseases.

Developmental delay is a failure to achieve developmental milestones when compared to similar-aged peers. Up to 40% of cases may be related to genetic factors, most commonly chromosomal anomalies and fragile X syndrome.

A patient with early onset diabetes and an affected parent may have an underlying genetic condition known as maturity-onset diabetes of the young, which can have implications for their diabetes management.

If diabetes is diagnosed in an individual under 25 years of age who has a parent or child with diabetes, this could be caused by a change in a single gene (monogenic) such as HNF1A maturity-onset diabetes of the young.