Three-dimensional craniofacial features of Glut1 deficiency syndrome patients

Glut1 deficiency syndrome is a neurological disease due to impaired glucose transport across blood brain barrier. The disease is consequence of mutations on gene SCL2A, encoding for protein GLUT1, which is responsible for glucose facilitated diffusion from intracellular to extracellular compartment. Mutations of this gene lead to a syndrome characterised by infantile seizures, developmental and cognitive delay, movement disorders, microcephaly and hypoglicorrachia. Currently, the diagnosis of this condition is clinical and genetic, but the recognition of some craniofacial features typical of the patients, and easily observable during a routine medical evaluation, could be of great help for an early diagnosis. In order to characterise the phenotype of Glut1 deficiency syndrome (Glut1-DS) patients and improve the diagnosis of the disease, a three-dimensional assessment of soft tissue facial features was made using stereophotogrammetry. We studied 7 patients with Glut1-DS. The three- dimensional coordinates of a set of standardised landmarks, previously identified on the face and then digitized on the three-dimensional facial reconstructions, were collected and used to calculate anthropometric linear distances and angles. Z scores, obtained comparing patients with healthy reference subjects, matched for gender, age and ethnicity, were used for comparisons. Results showed that Glut1-DS patients have a set of common craniofacial features; most of the anomalies were found in the mandible. Glut1-DS patients seem to have a more anterior chin; their mandibular body is longer but the rami are shorter, with a reduced gonial angle. Data can be of great interest to improve the diagnosis of this syndrome and to allow longitudinal evaluations of facial morphology in a safe and not invasive way. Nevertheless further evaluation on a larger sample is advised.