Sequencing technology is increasingly demonstrating the impact of genomic copy number variation (CNV) on phenotypes. Opposing variation in growth, head size, cognition and behaviour is known to result from deletions and reciprocal duplications of some genomic regions. We propose normative inversion of face shape, opposing difference from a matched norm, as a basis for investigating the effects of gene dosage on craniofacial development. We use dense surface modelling techniques to match any face (or part of a face) to a facial norm of unaffected individuals of matched age, sex and ethnicity and then we reverse the individual's face shape differences from the matched norm to produce the normative inversion. We demonstrate for five genomic regions, 4p16.3, 7q11.23, 11p15, 16p13.3 and 17p11.2, that such inversion for individuals with a duplication or (epi)-mutation produces facial forms remarkably similar to those associated with a deletion or opposite (epi-)mutation of the same region, and vice versa. The ability to visualise and quantify face shape effects of gene dosage is of major benefit for determining whether a CNV is the cause of the phenotype of an individual and for predicting reciprocal consequences. It enables face shape to be used as a relatively simple and inexpensive functional analysis of the gene(s) involved.

Original publication




Journal article


Hum Genet

Publication Date





1117 - 1125


Adolescent, Adult, African Continental Ancestry Group, Case-Control Studies, Child, Child, Preschool, Chromosome Disorders, Chromosomes, Human, Pair 11, Chromosomes, Human, Pair 16, Chromosomes, Human, Pair 17, Chromosomes, Human, Pair 4, Chromosomes, Human, Pair 7, DNA Copy Number Variations, European Continental Ancestry Group, Face, Female, Gene Dosage, Gene Duplication, Humans, Imaging, Three-Dimensional, Male, Phenotype, Sequence Deletion