Current use of chromosomal microarray by Australian paediatricians and implications for the implementation of next generation sequencing

Aim: Chromosomal microarray (CMA) is an important diagnostic test for children with multiple congenital anomalies or certain developmental behavioural problems suggestive of an underlying genetic diagnosis. However, there are medical and ethical complexities to its use and few Australian policies to guide practice. We aimed to describe the current practice of Australian paediatricians in relation to CMA testing. We hypothesised that there are knowledge gaps in their use of CMA.

Methods: Online survey completed between September 2015 and January 2016 by paediatricians in secondary care settings. Participants were members of the Australian Paediatric Research Network. One hundred and sixty five (43%) of 383 active members responded. Our main outcome measures comprised: (i) the indications for which paediatricians request CMA; (ii) their approach to consent; (iii) their interpretation of results; and (iv) their understanding of the impact on patient management.

Results: A significant proportion of paediatricians (21-52%) did not regularly use CMA for conditions with established evidence of diagnostic yield. Paediatricians under-estimated the potential for CMA findings to alter patient management. There was wide variability in paediatricians' approach to consent, and low use of consent forms and fact sheets. Paediatricians reported difficulties interpreting CMA results, with high rates of referral to clinical genetics services.

Conclusions: The reported practice of Australian paediatricians is not consistent with international standards on CMA. Australian practice could be improved by a standardised approach to ordering CMA, consenting patients and interpreting results. We provide resources for CMA ordering and make recommendations about preparation for next generation sequencing.