Fontaine-Farriaux syndrome: a recognizable craniosynostosis syndrome with nail, skeletal, abdominal, and central nervous system anomalies.

Craniosynostosis is an etiologically heterogeneous malformation, which may present as an isolated finding or in association with other anomalies. The concurrence of craniosynostosis together with specific central nervous system, abdominal, genital, and limb malformations defines the Fontaine-Farriaux syndrome, described so far in only two patients. We report on a stillborn who mainly presented severe intrauterine growth retardation, bilateral coronal synostosis, generalized nail hypo/aplasia more evident on the posterior side, tapered digits, mild cutaneous syndactyly, abdominal muscle hypoplasia, micropenis and bilateral cryptorchidism. Skeletal radiographs revealed universal platyspondyly and necropsy findings comprised intestinal malrotation, abnormal cortical gyral formation, periventricular heterotopia, and cerebellar hypoplasia. Comparison between the present and the two previously described patients demonstrates that our case shows a combination of features strikingly resembling the original description. Conversely, the second reported patient shows a very atypical phenotype and is, most probably, affected by a distinct clinical entity. The triad of craniosynostosis, anonychia, and abdominal muscle hypo/aplasia emerges as the most consistent core phenotype, although skeletal and brain anomalies are relevant ancillary findings. An in-depth differential diagnosis with other partially overlapping conditions is carried out.