Pilot study for subgroup classification for autism spectrum disorder based on dysmorphology and physical measurements in Chinese children

Abstract

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder

affecting individuals along a continuum of severity in communication, social

interaction and behaviour. The impact of ASD significantly varies amongst

individuals, and the cause of ASD can originate broadly between genetic and

environmental factors.

Previous ASD researches indicate that early identification combined with a

targeted treatment plan involving behavioural interventions and multidisciplinary

therapies can provide substantial improvement for ASD patients. Currently there

is no cure for ASD, and the clinical variability and uncertainty of the disorder still

remains. Hence, the search to unravel heterogeneity within ASD by subgroup

classification may provide clinicians with a better understanding of ASD and to

work towards a more definitive course of action.

In this study, a norm of physical measurements including height, weight, head

circumference, ear length, outer and inner canthi, interpupillary distance, philtrum,

hand and foot length was collected from 658 Typical Developing (TD) Chinese

children aged 1 to 7 years (mean age of 4.19 years). The norm collected was

compared against 80 ASD Chinese children aged 1 to 12 years (mean age of 4.36

years). We then further attempted to find subgroups within ASD based on

identifying physical abnormalities; individuals were classified as

(non)dysmorphic with the Autism Dysmorphology Measure (ADM) from physical

examinations of 12 body regions.

Our results show that there were significant differences between ASD and TD

children for measurements in: head circumference (p=0.009), outer (p=0.021) and

inner (p=0.021) canthus, philtrum length (p=0.003), right (p=0.023) and left

(p=0.20) foot length. Within the 80 ASD patients, 37(46%) were classified as

dysmorphic (p=0.00).

This study attempts to identify subgroups within ASD based on physical

measurements and dysmorphology examinations. The information from this

study seeks to benefit ASD community by identifying possible subtypes of ASD

in Chinese population; in seek for a more definitive diagnosis, referral and

treatment plan.