Yongguo Yu is what the Chinese refer to as a "sea turtle," a professional who has received his education or pursued a career abroad, only to put any skills acquired to use upon return to his native country. After three years using microarrays in the department of laboratory medicine at Boston Children's Hospital, Yu brought his fondness for the technology with him when he decided to join Shanghai Children's Medical Center a year ago.
While Yu has used arrays to identify the causes of developmental delay in 700 patients since introducing testing on the Affymetrix CytoScan HD platform, he said there is room for improvement when it comes to using chromosomal microarrays in China. In particular, he believes that Chinese cytogeneticists could share data more often, and that a custom array optimized for the Chinese population might be a better fit for diagnosing the causes of local patients.
BioArray News interviewed Yu at a workshop for chromosomal microarray users in Hangzhou, China, earlier this month. Below is an edited transcript of that conversation.
What are your responsibilities in your position at the hospital?
Mainly, I am a genetics doctor. I am trying to explain the developmental delay of patients and discover the reason for it and prescribe some treatment.
When did you start using microarray technology in the lab?
I just came back to China a year ago. I was at Harvard Medical School, and also at Boston Children's Hospital for three years. And so I have been using the CytoScan HD array for [several] years. At Boston Children's Hospital, I used it for about 300 cases.
Why did you decide to use CytoScan?
I think different array platforms have their advantages and shortcomings. I chose Affy because of its higher density and [higher] sensitivity for detecting regions of loss of heterozygosity. Also, I had used Affy in Boston too, so I was familiar with it.
In the US, the array is just another tool. It's a mature technology. But in China it is a new technology. I think arrays will replace G-banded karyotyping. When I came back I set up the lab and I did 100 normal children samples and compared Affy, Agilent, and Illumina. And I decided to choose the Affy platform. I think that the array improved the analysis.
Were your fellow researchers aware of the technology? What did they think about using the technology?
They partly did not know this technology as it is very new and very expensive. And they were unaware of its advantages.
Did you seek assistance from Affymetrix in setting up the facility?
No, I set it up by myself. In our hospital, I see the patient and I order the test, and our molecular lab produces the data. Also, they will interpret the data and produce a report that can be used for consulting with a patient.
There have been some issues with findings of unclear significance and how to relay that information back to patients. What have you decided to do?
This is very challenging. We rely on different strategies. And we have many data resources. We have our own database and we also can use Boston Children's Hospital's database of 10,000 cases. If we discover a new CNV, I can just ask Boston Children's Hospital, and see if it is de novo or pathogenic or not or inherited. We have many resources to care for these patients and interpret their CNVs.
How would you characterize cooperation between other geneticists using chromosomal microarrays in China?
I think that in China, geneticists tend to work on their own rather than with each other. But I would like to see more of us work together and more data sharing.
Patients currently pay for these tests out of pocket, but is there any sign that the state could reimburse these tests?
No. It is very complex. It is government politics. So the patients have to pay for these tests themselves. But many people in Shanghai now have the resources to pay for them.
What do the people who pay for these tests expect from the technology?
If there is a child that is affected, they want to know what is the cause, and what treatment can be used. However, most developmental delays cannot be treated. Only a few cases can be treated. But these findings can also be used to prevent the birth of similarly affected children. I don't do prenatal testing, but it can give an indication of where to look in the genome so that second children will not suffer from the same abnormality.
So if someone comes in with a child with an abnormality and you determine what the cause of that abnormality might be, could you refer the case to a prenatal geneticist?
Yes, that's right, perhaps to another hospital.
Do you know to what extent arrays are being used in prenatal testing?
Not frequently. It is a new technology.
How could the product you use be improved?
We are working on a custom design focused on Chinese patients. We hope this custom array will come out in maybe half a year, because the probes need to be confirmed. The availability of such an array will allow the patient to be able to feel comfortable with the results. Cost is also big issue. The cost is still too high. I know that at Boston Children's Hospital, the cost of a test was $1,700.
There is an idea that most geneticists using traditional karyotyping will move to an array platform. Do you think that will happen?
Not completely, because FISH has its advantages. For example, an array can find a very low-sized copy number change and FISH still needs to be used to confirm it. But more labs will use arrays, because the cost of FISH is also expensive, and because FISH only detects a few regions of copy number change, but arrays detect a whole genome. In China FISH is very expensive. So I think that arrays are better. You can get more information for the same price.