Automatic analysis of local nasal features in 22q11.2DS affected individuals.

The 22q11.2 deletion syndrome is a common genetic condition with an estimated prevalence between 1:2000 and 1:6000 live births in the US. The syndrome is manifested in multiple different craniofacial features. The nasal area is known to play a role in assessing the extent of dysmorphology of an individual patient. In this paper, we present a method for detecting and assessing the severity of a common nasal feature: the bulbous nasal tip. Our method locates the nose and computes four descriptors, each of which leads to a severity score. Experiments with the four severity scores and a combinations of the best two show that using all five scores gives the best prediction of bulbous nasal tip. Furthermore, the bulbous nasal tip measures outperformed the median of human experts and attains similar results to our own prior work on global descriptors [12] for prediction of 22q11.2DS.