Genetics

Recently, there was significant attention in the press to a review article by Andres Moreno-De-Luca and colleagues at the Genomic Medicine Institute, Geisinger Health System, and the Department of Human Genetics, Emory University. (See the full article citation below.)  The article entitled “Genetic insights into the causes and classification of the cerebral palsies” indicates that there is a growing body of evidence suggesting that more cases of cerebral palsy are caused by genetic or inherited factors than previously appreciated.  It is the authors’ opinion (It should be stressed that this is opinion, not fact.) that genetic factors may account for 70-80% of cases attributed to prenatal causes of cerebral palsy.  Furthermore, genetic factors may predispose to certain known risk factors for cerebral palsy, such as premature birth, bleeding or clotting abnormalities leading to stroke, and difficult births.  They provide an excellent summary of existing evidence that supports the role of genetics in cerebral palsy.

I asked experts at the University of Adelaide, Australia, who have conducted research on the genetic relationships to cerebral palsy, to comment on this article.

“Although the article published in Lancet Neurology by Moreno-De-Luca et al. is important and extensive, to date one cannot yet say that large numbers of CP have a genetic origin.  It would be inappropriate to suggest to families with a CP child that there are commercially available genetic tests to ascertain all the possible genetic variations that may or may not be associated with CP.  It will take much more and expensive research to ascertain the percent of CP that has genetic origins and for us to be sure which genetic variations are truly pathogenic and responsible for the CP outcome. So although there are exciting horizons for genetic research in CP we cannot yet offer clinical tests or intervention and must advocate a conservative approach.”

 

Gai  McMichael, MPhil

Research Scientist

Cerebral Palsy Research Group

Robinson Institute


Professor Alastair H MacLennan AO,

MB,ChB, MD, FRCOG, FRANZCOG,

Discipline of Obstetrics & Gynaecology,

The University of Adelaide, AUSTRALIA

 

 

Thus, we have two differing opinions on the role of genetics in cerebral palsy, given the current state of knowledge.  Both the authors of the article and the experts from Australia agree that genetics is a factor in some, perhaps many, cases of cerebral palsy.  The disagreement is in how certain we can be about the percentage of those cases at this time and whether there is sufficient knowledge about this relationship to warrant extensive and expensive genetic testing in every case, especially when there is confidence about the cause.  This may be yet another instance where technology has advanced faster than the ability of a clinician to interpret the results of very sophisticated genetic tests. It is often difficult to interpret various abnormalities that may be revealed – that is, do they have anything to do with the condition being tested for?  Until we know what such abnormalities mean, they may serve only to frighten and worry parents or individuals with cerebral palsy.  This would clearly be the case if such testing were done as part of prenatal counseling.

The Moreno-De-Luca article serves to call attention to a possibly more prominent role of genetics in cerebral palsy than previously appreciated. However, a call for universal genetics testing of all individuals with cerebral palsy may be premature at this time. Rather, individualizing such recommendations as part of a comprehensive care plan would seem sensible. Persons with or parents of children with cerebral palsy interested in a possible genetic cause should discuss this question with an expert in cerebral palsy, such as a developmental pediatrician, neurologist, or physiatrist.  Additional consultation with a genetics expert might be warranted in some cases.

 

Reference:

Moreno-De-Luca A, Ledbetter DH, Martin CL. Genetic insights into the causes and classification of the cerebral palsies. Lancet Neurology 2012:11:283-292