Glossary and further reading

Finding out more about genetics and the NHS can involve lots of jargon and technical words. We’ve pulled together a quick guide to some of these terms to help you at the start of your journey.

Term Explanation
Autosomes The set of chromosomes that are the same in males and females.
Blood test A scientific examination of a sample of blood, typically for the diagnosis of illness.
Carrier An unaffected individual that carries one copy of a gene that is linked to a recessive condition
Chromosome Structures of DNA that contain our genetic information, made up of many genes. Humans have 22 pairs of autosomes and one pair of sex chromosomes.
Chromosomal disorder A condition caused by an abnormal chromosome change in early development.
Clinical trial Research studies evaluating the effectiveness and safety of medications or medical devices by monitoring their effects on large groups of people.
Complex disorder Complex disorders (also known as multifactorial or polygenic) are those that are caused by the simultaneous effect of many different genes, often in a complex interaction with environmental and lifestyle factors such as diet.
Developmental delay When a child takes longer to reach certain developmental milestones than other children of the same age (for example, developmental milestones like rolling over, sitting up, walking and talking).
Diagnostic odyssey A term used to describe the journey from initial disease recognition or onset of symptoms to a final diagnosis.
Diagnostic test Tests used to gather clinical information for the purpose of making a diagnosis.
DNA The molecule that encodes genetic information. In the same way computers are coded in 0’s and 1’s, our code is written in DNA.
Dominant inheritance A mode of inheritance in which only one copy of a gene is needed to give the individual that gene’s characteristic.
Gene A length of DNA that codes for a certain characteristic.
Genetic counselling A service provided by trained healthcare professionals that offers information, support and advice about genetic conditions.
Genetic testing A medical test that can identify a faulty gene or chromosome that causes a genetic condition.
Genetics The study of genes, genetic variation and inheritance of genetic traits.
Genome The entire genetic material of an organism.
Genotype The gene or set of genes that gives rise to a certain characteristic.
Multifactorial disorder See complex disorder.
Non-genetic condition A condition not relating to or involving genes or chromosomes.
Polygenic disorder See complex disorder.
Predictive test Testing used to identify genetic changes linked with a condition before you show symptoms.
Rare condition A condition that affects fewer than 1 in 2,000 people.
Recessive inheritance A mode of inheritance in which two copies of a gene are needed to give the individual that gene’s characteristic.
Respite care Short-term care that is provided to allow parents/carers to have a break.
Saliva test A diagnostic technique involving laboratory analysis of saliva to identify markers of a particular condition.
Sex chromosomes The set of chromosomes that determine your sex – XX in females and XY in males.
Single gene disorder A genetic condition caused by only one gene.
Tissue test The removal of a small amount of tissue which is then analysed in a laboratory to identify a particular condition. 
X-linked inheritance A mode of inheritance in which a gene is carried on the X-chromosome, meaning that a child’s sex will determine their likelihood of inheriting the gene’s characteristic.

Having a genetic, rare or undiagnosed condition might mean having to see a number of different healthcare professionals. Here is a guide to their roles. 

Allied health professional (AHP) A term for a health professional that is not a doctor or nurse. For example, physiotherapists, occupational therapists and speech and language therapists. 
Clinical nurse manager A nurse responsible for the management of ward or a unit. 
Clinical nurse specialist A nurse who has undertaken specialist training to become an expert in one area of healthcare.
Clinical support worker (or auxiliary nurse) Assists registered nurses with patient care.
Consultant A consultant is a senior doctor who practises in one of the medical specialities. 
District Nurse A nurse that looks after patients in the community.
General Practitioner (GP) A doctor based in the community who treats patients with minor or chronic illnesses and refers those with serious conditions to a hospital.
Genetic Counsellor A health professional trained to provide support, information and advice about genetic conditions. 
Genetic Nurse A registered nurse with a special education and training in genetics.
Health Visitor A qualified and registered nurse or midwife who has chosen to gain additional training and qualifications. They mainly work in the community with children from birth to five years old and their families. 
Midwife A qualified health professional that cares for women throughout pregnancy, birth, and during the postnatal period, as well as caring for newborn babies. 
Occupational Therapist (OT) An AHP who promotes health and wellbeing through the use of particular activities as an aid to recuperation or self-management of a condition. 
Paediatrician A medical practitioner specialising in the physical, mental and social health of children from birth to young adulthood. 
Pharmacist A health professional who is an expert in medicines and their use. They advise medical and nursing staff and provide information to patients. 
Physiotherapist Helps people affected by injury, illness or disability through movement and exercise, manual therapy, education and advice. They provide advice on pain management. 
Practice nurse A nurse who works in the community, usually in a GP surgery or local health centre. 
Specialist consultant Doctors who have completed advanced education and clinical training in a specific area of medicine.
Speech and Language Therapist An AHP who addresses speech, language and communication problems. 

Many doctors and healthcare professionals have extra expertise in a particular medical speciality. 

Here is a list and explanation of a number of specialities that you may encounter.

Term Speciality
Cardiology Speciality dealing with conditions of the heart.
Clinical neurophysiology Speciality dealing with conditions of the nervous system. 
Dermatology Speciality dealing with conditions of the skin.
Endocrinology Speciality dealing with conditions of the endocrine system (hormones).
Gastroenterology Speciality dealing with conditions of the stomach and intestines.
Genetics  Speciality dealing with diagnosis and management of genetic conditions. 
Haematology Speciality dealing with conditions of the blood.
Immunology Speciality dealing with conditions of the immune system.
Nephrology Speciality dealing with conditions of the kidneys.
Neurology Speciality dealing with conditions of the nervous system.
Obstetrics and gynaecology Speciality dealing with pregnancy, childbirth and care for the mother and child in the weeks following childbirth.
Oncology Speciality dealing with prevention, diagnosis and treatment of cancers.
Ophthalmology Speciality dealing with disorders and diseases of the eye.
Orthopaedics Speciality dealing with bones and muscles.
Otorhinolaryngology Speciality dealing with conditions of the ear, nose and throat.
Paediatrics Speciality dealing with the medical care of infants, children and adolescents.
Podiatry Speciality dealing with foot, ankle and lower extremities.
Psychology Speciality dealing with the mind and behaviour.
Radiology Speciality using medical imaging techniques including x-rays and scans.
Respiratory medicine Speciality dealing with conditions of the respiratory system (breathing) and lungs. 
Rheumatology Speciality dealing with conditions that affect joints, tendons, ligaments, bones and muscles. Includes many types of arthritis.
Urology Speciality dealing with conditions of the urinary system.
Vascular Speciality dealing with the circulatory system (arteries, veins etc)  and lymphatic system.

Further reading


You may want to learn more about genetics and rare diseases. There are lots of good books to help, and we’ve listed just a few of them here.

We’ve signposted to Amazon since this is accessible across the UK, but most of these resources are available from other online retailers and local bookshops too.

See Inside Genes and DNA (an ‘open the flap’ book suitable from primary school upwards)

Extraordinary! A book for children with rare diseases (suitable from primary school upwards)

The Code of Life (a picture book suitable from secondary school upwards)

Unique Tales (a graphic magazine produced by our member charity Unique to support siblings of children with rare genetic conditions)

Genes – a very short introduction (text only and suitable from further education upwards)

Genomics – a very short introduction (text only and suitable from further education upwards)

If you have seen a great book or resource that we should consider adding to this list, please let us know by emailing [email protected].