LAUSR

Greig cephalopolysyndactyly syndrome (GCPS). GCPS is a rare autosomal dominant genetic condition characterised by polydactyly, cutaneous syndactyly, macrocephaly, possibly associated with frontal bossing, and ocular hypertelorism. Polydactyly is usually pre-axial, that is involving the first ray, or mixed (pre and post-axial, the latter involving the fifth ray). This patient had a distinctive limb malformation with a post-axial involvement of both hands and a pre-axial involvement of both feet, known as crossed polydactyly and already described in GCPS. In GCPS, various neurological manifestations may infrequently appear, including seizures, developmental delay, and intellectual disability (incidence rate of <10% altogether), while hypoplastic or absent corpus callosum is described in around 20% of patients. In our patient, neurological development was age-appropriate, and the corpus callosum was identified by neonatal cerebral ultrasound. GCPS is caused by pathogenic heterozygous mutations or deletions involving GLI3, a key gene for limb development, located on chromosome 7p14.1. In this case, whole exome sequencing was performed to confirm the clinical hypothesis of GCPS: the Fig. 1 (a) Scattered vesicles, erosions, eschars, haemorrhagic crusts, pitted scars and oedema. (b) Close-up to vesicle, pitted scars and eschars. (c) Histopathology showing epidermis with vacuolar degeneration of the basal layer associated with an intraepidermal vesicle. Dermis with a dense lymphocytic infiltrate around the adnexa and blood vessels (haematoxylin and eosin, 20). (d) Positive in situ hybridization technique for Epstein–Barr virus. Case Images