Genetic studies in paediatrics
When is genetic testing in children necessary?
How can we help you?
Non-obligation guidance
What are they and what are they for?
Genetic studies in paediatrics are a set of tests performed to analyse a child's DNA in order to identify possible genetic alterations or mutations that may be the cause of a disease or medical condition.
Types of genetic diseases
Genetic diseases can be of different types depending on their origin:
- Monogenic diseases: caused by changes in the DNA sequence called mutations or pathogenic variants.
- Chromosomal syndromes: caused by chromosomal alterations (numerical or structural).
- Genetic imprinting diseases: alterations in gene expression due to DNA marks that are not sequence changes.
Incidence
Genetic diseases are a very heterogeneous group and their incidence varies considerably, being relatively high. About 1-3% of newborns are born with some type of genetic disorder.
Diagnostic tests.
The diagnosis of a genetic disease is made by means of different tests, such as:
- Karyotyping: analysis of the chromosomes.
- Array-CGH: analysis of the DNA amount in each chromosome
- MLPA - analysis of the DNA amount of specific genes
- Gene panels: analysis of a group of genes related to a specific disease
- Genetic study: analysis of the most frequent mutations or of the entire gene (e.g. CFTR gene responsible for cystic fibrosis).
- Genetic study of Fragile X syndrome: analysis of the number of repetitions of the CGG triplet of the FMR1 gene, located on the X chromosome.
- Clinical exome: Analysis of disease-associated genes.
- Whole exome: analysis of all genes (coding regions only).
- Whole genome: analysis of all DNA (coding and non-coding regions).
How does genetic testing help the medical specialist?
The genetic study is useful to confirm or rule out the diagnosis of a genetic disease, to predict the course of the disease and to propose specific treatment options for the patient. In addition, if inherited from parents, it allows genetic counselling to be offered to the family in order to:
- Identify other family members who may be at risk.
- Assess the couple's risk in case of reproductive desire.
- Offer different reproductive options (prenatal diagnosis, pre-implantation diagnosis or gamete donation).
In which cases is it indicated?
- Clinical suspicion of chromosomal alteration (example: Turner Syndrome)
- Clinical suspicion of a specific genetic disease (e.g. Charcot-Marie-Tooth, Deafness, Osteogenesis imperfecta...).
- Family history of genetic diseases
- Developmental delay
- Intellectual disability
- Autism Spectrum Disorders (ASD)
- Congenital malformations
- Epilepsy
- Kidney disease
- Heart disease
- Childhood cancer
- Imprinting diseases (e.g. Beckwith-Wiedemann, Prader-Willi or Angelman syndrome)
What would be the appropriate diagnostic test?
|
Clinical suspicion of chromosomal alteration |
Karyotype, Array-CGH |
|
Clinical suspicion of a specific genetic disease |
Disease-related gene panel (or study of a specific gene) |
|
Family history of genetic disease |
Disease-related gene panel (or study of a specific gene) |
|
Developmental delay |
Karyotype, Array-CGH, Fragile X study, Clinical exome, Whole exome |
|
Intellectual disability |
Karyotype, Array-CGH, Fragile X study, Clinical exome, Whole exome |
|
Autism spectrum disorders |
Karyotype, Array-CGH, Fragile X study, Gene pane, Clinical exome, Whole exome |
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Congenital malformations |
Karyotype, Array-CGH, Clinical exome, Whole exome |
|
Epilepsy |
Gene panel, Clinical exome, Whole exome |
|
Renal diseases |
Gene panel, Clinical exome, Whole exome |
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Heart diseases |
Gene panel, Clinical exome, Whole exome |
|
Childhood cancer |
Gene panel, Clinical exome, Whole exome |
|
Imprinting disease |
Specific molecular test |
Author: Ruth Morales