Fetuses with a specific, rare chromosome aberration have a 20 percent risk of developmental or other brain disorders, new research shows. The work could lead to personalized diagnostics and counseling for pregnant women.
Fetuses with this new balanced chromosomal aberration have a higher risk of developing brain diseases such as autism and mental retardation than previously thought American Journal of Human Genetics .
"We identified all people who diagnosed such chromosomal aberration as fetuses in Denmark, and we can see that they have more commonly developed a disease," says study co-author Iben Bache, adjunct professor in the Department of Cell and Molecular Medicine at the University of Copenhagen, Faculty of Health and Medical Sciences and Physician in the Department of Clinical Genetics at Rigshospitalet
"We did not know which analyzes to discriminate are the fetuses that will be healthy by those who eventually have disorders
"The previous study, which found a risk of 6-9 percent, mainly referred to congenital malformations and did not include neurocognitive disorders such as autism and mental retardation, which often occurred later.
" The extent of the overall risk is therefore unknown to us, "says Bache, 1
The study is the largest systematic review of these rare chromosome aberrations in fetuses and will also evaluate the methods These chromosomal abnormalities are diagnosed by chorionic villus sampling or amniocentesis using classical chromosome analysis, which microscopically studies the genetic material, a method that has been used for the last 40 years and is still the method used in most pregnancies worldwide
Another method, the so-called chromosomal microarray, is increasingly replacing the method in Danish hospitals: the chromosomal microarray tests exclusively for the loss and gain of the genetic material and can therefore account for the rare, balanced aberrations i n discover the new study. In contrast, the study shows that modern genome sequencing is in most cases not only able to detect these balanced chromosomal aberrations, but also whether genes have been damaged.
The researchers carefully examined the Danish health records to find all de novo balanced chromosomal aberrations since 1975. Each time they found a person with the abnormality, they produced a control group of five individuals with normal chromosomes, more or less simultaneously were born to a mother of the same age. 196590000] The researchers then visited the majority of individuals to conduct a health examination and collect blood samples for advanced genetic analysis. By comparing the group's health data with the chromosome aberrations and the control group, the researchers found that they were two to three times more likely to develop a neurocognitive disorder in the chromosome aberration group.
Discovery continues to make assumptions about birth defects  In addition, the researchers found that the new genome sequencing techniques are much better than any other technique to assess the health effects of balanced chromosomal aberration. This is the conclusion of almost identical assessments made by two independent research groups, including a group from Harvard Medical School.
"We did not know which analyzes would be used to differentiate the healthy fetuses from those that would later develop disorders." Our study shows that we can actually discriminate in a number of cases with the new sequencing technologies, "says Bache. "This can severely affect the diagnosis and counseling of pregnant women who have fetuses with this specific type of chromosome aberration in the future."
The observation of brains in infancy may indicate future diseases
The funding came from the Lundbeck Foundation through the Danish National Research Foundation. The study was a collaboration between researchers from the University of Copenhagen who are conducting basic research, all clinical gene departments in Denmark, and the Department of Epidemiological Research at the Statens Serum Institute.
Source: University of Copenhagen