What is a genetic syndrome?
A genetic syndrome, or genetic disorder, is a genetic problem or condition which occurs as a result of an abnormality (or more than one) in the genome. Genetic disorders can be passed down from parent to child (hereditary), or they may be a result of changes to the individual's DNA or specific mutations. Most types of genetic disorder are rare, affecting one in every several thousand, if not more. Some types of genetic disorder include Down's syndrome, cystic fibrosis, Huntington's disease, and sickle-cell anaemia. ‘Syndrome’ is defined as a disease or disorder that has numerous symptoms or identifying features. Hence, genetic syndromes will often many typical features.
Prognosis of genetic syndromes:
The prognosis of genetic syndromes varies according to each type. Certain syndromes do not have many treatment options available and will have a quick progression in symptoms. Other syndromes won’t show symptoms until later in life. Additionally, some genetic syndromes are so rare that few patients have been identified or studied, making treatment advances difficult.
Symptoms of genetic syndromes:
The symptoms vary according to each syndrome, however, they will usually have a mix of physical and neurological symptoms.
For example, the symptoms of Down’s syndrome are:
- Flat facial features
- Smaller head and ears
- Short neck
- Poor muscle tone
- Impulsive behaviour
- Short attention span
- Slow learning abilities
- Poor vision
- Hearing loss
- Heart defects
Medical tests to diagnose genetic syndromes:
Some genetic syndromes can be diagnosed before birth using prenatal tests such as an amniocentesis or CVS. Down’s syndrome is one that can be identified at this stage. Genetic syndromes may also be diagnosed on the basis of a physical examination, as some will have very specific and defined physical characteristics. Genetic testing will also be able to confirm what genetic syndrome is presented.
What are the causes of genetic syndromes?
There are different types of genetic syndrome, with the genetic cause differing slightly:
- Single gene disorders – caused by a defect in one gene (e.g. Huntington’s disease, cystic fibrosis and muscular dystrophy).
- Chromosome disorders – caused by changes in either the number or the physical structure of the chromosomes (e.g. Down’s syndrome).
- Multifactorial disorders (complex disorders) – caused by a mix of environmental factors and gene mutations (e.g. cancer, heart disease, diabetes).
Can genetic syndromes be prevented?
Whilst babies born with genetic syndromes cannot avoid their progression, treatments can help to manage symptoms. Some parents who are aware of a genetic syndrome in their family, they may choose to undergo genetic testing during pregnancy, or preimplantation genetic diagnosis if they are undergoing IVF. This means that a developing baby that tests positively for a genetic syndrome can be aborted, if appropriate. If you choose to have PGD before IVF, only the embryos that do not have the chromosomes for a genetic syndrome will be implanted.
Treatments for genetic syndromes:
Treatment differs for each type of syndrome, but will usually be a mix of special support (e.g. learning support), medications, and surgeries to correct defects (e.g. heart surgery).
Which type of specialist treats genetic syndromes?
Genetic syndromes are treated by numerous specialists, including obstetrics and gynaecologists, clinical geneticists, cardiologists, psychologists and paediatricians.