Often, birth defects occur because of variations in children's genes. Researchers are learning that those genetic differences can also influence other disorders.
A recent study compared a group of children with kidney and urinary tract defects to children without these birth defects. This study found that one in ten children with the defects had genetic variations that are linked to developmental delays.
This means that children with kidney or urinary tract defects appear more likely to have genetic disorders that could contribute to neurological or mental health conditions.
The study, led by Simone Sanna-Cherchi, MD, from the Division of Nephrology at Columbia University, looked at the genetic mutations found in children with kidney and urinary tract birth defects.
The researchers compared 522 children who had a kidney defect called renal hypodysplasia with 13,839 children in the general population who did not have it. They were specifically looking at certain types of genetic mutations or alterations in the children that were abnormal.
The researchers found that 55 of the children with kidney defects (10.5 percent) had 34 different known genetic alterations that are also linked to developmental delays or neurological or psychiatric disorders. Yet only 0.2 percent of the children in the general population had these alterations in their genes.
The researchers also found new genetic alterations in 32 of the children with kidney defects (6.1 percent) which they had not seen before – though most of these new variations were in just one child. These genetic variations could be new genetic disorders.
When the researchers looked at the children who had multiple birth defects, 22.5 percent of them also had genetic alterations, and 14.5 percent of the children with only birth defects in their urinary tract had these genetic alterations.
This means that a little over 10 percent of children born with kidney defects appear to have genetic variations that are linked to neurodevelopmental disorders.
"This changes the way we should handle these kids," said co-author and kidney specialist Ali Gharavi, MD, in a release about the study. "If a physician sees a child with a kidney malformation, that is a warning sign that the child has a genomic disorder that should be looked at immediately because of the risk of neurodevelopmental delay or mental illness later in life."
According to Dr. Sanna-Cherchi in the release, these findings may help explain behavioral differences already observed in children with these kidney or urinary tract defects.
"If you talk to clinicians, they tell you that some of these kids behave differently," Dr. Sanna-Cherchi said. "There has been a general assumption, though, that behavioral or cognitive issues in children with chronic illnesses such as kidney disease stem from the child's difficulty in coping with the illness. Our study suggests that in some cases, neurodevelopmental issues may be attributable to an underlying genomic disorder, not the kidney disease."
According to background research in the paper, about a quarter of all birth defects in the US are related to the kidneys or urinary tract. They occur in about 1 of every 200 births.
The study was published in the December issue of the American Journal of Human Genetics. The research was supported by the Italian Telethon Foundation, the American Heart Association, the American Society of Nephrology, the National Institute of Diabetes and Digestive and Kidney Diseases, the Fondazione Malattie Renali nel Bambino, the Doris Duke Charitable Foundation, the the Polish Ministry of Health, the National Institutes of Health, the Parkinson’s Disease Foundation, the British Heart Foundation, the European Community Framework 6 Network of Excellence InGenious HyperCare, the National Institute on Aging and the Wellcome Trust.