It’s a boy! Now where’s that genetic testing kit? 

February 28th, 2018



In a big step forward for early diagnostic use, US company Sema4 has begun offering a newborn genetic screening kit that analyses 166 genes for 193 disorders and 38 common pediatric diseases. Sema4 is a “health information company founded on the idea that more information, deeper analysis, and increased engagement will improve the diagnosis, treatment, and prevention of disease.” To coincide with Rare Disease Day (28 February, 2018) we discuss the implications of the test, not only for parents discovering their new baby carries an unexpected disease, but for national newborn screening programs (or the lack of) and the future of biochemical testing. 

The genetic test, which analyses saliva instead of blood, is called Natalis and can be ordered directly by parents with authorisation from a physician. It costs US$649, which includes a post-result counselling session. It is approved only if the child has not shown any symptoms (i.e., is ‘asymptomatic’). Sema4 say, “This test only screens for conditions that may be treated with medication, dietary modification, or other therapies.”  

It’s seen as a high-level addition to any standard newborn screening program already in place. In the US, for example, states offer a diagnostic screening test for around 34-50 conditions while in the UK, the NHS offers the heel prick test to all new babies which looks for fewer conditions, including sickle cell anaemia, cystic fibrosis, congenital hypothyroidism and maple syrup urine disease. The Netherlands tests for 17 conditions, in France it’s five, Denmark tests for 13, Germany 12,1 and Italy has recently expanded its testing from three to 40 diseases. 

This new diagnostic service raises plenty of questions: 

  • The test is done at home and even though the procedure is simple – a cheek swab taken from the baby and preferably both parents – is it something parents should undertake by themselves?
  • The baby must be asymptomatic of any known disease. How does a parent know if a new baby is asymptomatic without a physician’s opinion? 
  • Will there be adequate follow-up, apart from the counselling session, to ensure that a child receives the correct care once a condition is diagnosed, or will parents have to navigate the next steps by themselves?  
  • If it only diagnoses conditions where medical treatment is available, how will parents react if they get an all clear and then find out the baby has a condition for which there is no current treatment? 
  • Are kits like this a valid option in countries without a national newborn screening program (or a very limited one)? Could the availability of such a diagnostic test be seen as a ‘get-out clause’ to avoid developing a comprehensive national newborn screening program, leaving the option to test with wealthy parents only? 
  • Does this signal the end for biochemical testing and herald a new age of genetic newborn screening? If so, would a national health service ever be able to find a cost-effective way to test for the range of conditions offered by Natalis? Or is a pharma partnership to subsidize genetic testing the likely route?  

The manufacturer believes that early detection of treatable conditions is better for the patient and for the healthcare services, as prevention or management of a condition could be a better option, physically and financially, than long-term pharmaceutical or hospital therapy. While many questions remain to be addressed, as proponents of high quality and timely diagnostic testing throughout the patient journey, Diaceutics are encouraged to see such new developments in the diagnostic space.   

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3872591/ 

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