• Congenital malformations and/or dysmorphism highly suggestive of an underlying monogenic disorder where targeted genetic testing is not possible.
• Unexplained moderate/severe/profound global developmental delay or unexplained moderate/severe/profound intellectual disability, and where clinical features are highly suggestive of an underlying monogenic disorder requiring sequencing and targeted genetic testing is not possible.
• Craniofacial dysmorphism in combination with additional issues with health or development suggestive of a single genomic explanation, e.g. intellectual disability, congenital malformation, organ dysfunction.
• Syndromic overgrowth or overgrowth in combination with intellectual disability or developmental delay.
• Adults with congenital malformation and dysmorphism syndromes, however the clinical utility of testing should be made clear on the request form e.g. to inform a clinical management decision or reproductive choice.
• Fetus from a demised/non-continued pregnancy, with multiple major structural abnormalities detected on fetal ultrasound or post-mortem examination and where a monogenic malformation disorder is considered highly likely
• Unexplained epilepsy with clinical suspicion of a monogenic cause including onset under 2 years, OR clinical features suggestive of specific genetic epilepsy, for example Dravet syndrome.

Exclusion criteria
• Isolated Congenital Heart Disease and other isolated congenital malformations where the likelihood of a monogenic disorder is low are not eligible for testing under this indication.
• Isolated craniofacial dysmorphism is not an indication for testing; exceptions to this can only be made following multidisciplinary discussion with clinical genetics.

R28 microarray testing is not a requirement prior to R27 being initiated in patients with a possible monogenic cause of a syndromic paediatric disorder in whom there are no recognisable features of a specific chromosome disorder (eg 22q11 deletion syndrome).