Craniofacial dyssynostosis (CD) is a very rare syndrome caused by premature fusion of certain cranial sutures. It has been reported in the surgical literature as Mercedes Benz syndrome; named as such because of the characteristic appearance of the fused sutures on three-dimensional CT imaging. The condition is characterized by a dolicocephalic skull, protruding forehead, small, bulging or flat occiput, macrocephaly, maxillary hypoplasia, mental retardation, seizures, and a short stature. Certain other features may also be noticed in the condition, including severe global developmental delay, epilepsy, and oculomotor dyspraxia. Brain MRI may reveal agenesis of the septum lucidum and posterior portion of the corpus callosum, thinning of the gray matter, and gray matter heterotopia in cerebral hemispheres. Early diagnosis of the condition is important, as mental retardation may occur without early surgical intervention. In the case of timely surgical correction, normal development is seen.
Only a handful of patients have so far been reported with this condition. Two of the earliest patients reported were sisters, and some others were from consanguineous families, suggesting an autosomal recessive inheritance for the condition. Although the gene defect involved in the pathogenesis of the condition is not known, some researchers have suggested a higher allele frequency of the defect among the Spanish.
Al-Torki et al. (1998) reported the first Arab patient affected with craniofacial dyssynostosis. The boy was born at term to normal non-consanguineous parents, who had five healthy daughters. Fetal US at 28-weeks gestation had shown a large head and large anterior fontanel/sutures. At 3.5 years of age, the boy's height was at the 75th, weight at 3rd, and OFC at 90th centile. By this time, examination revealed the following: developmental delay, an abnormal facial appearance, seizures, agenesis of corpus callosum, dolichocephalic skull, prominent occiput and a metopic suture, frontal bossing, broad nasal bridge, hypertelorism, shallow supraorbital ridges, down-slanting palpebral fissures, midfacial hypoplasia, low-set posteriorly angulated ears, long philtrum, a down-turned mouth, hypotonia, and a right cryptorchidism. Brain CT scan had revealed a subdural hygroma at the age of 3-months, which was shown to reduce in size with time. Al-Torki et al. (1998) diagnosed the condition as craniofacial dyssynostosis, in spite of the presence of normal stature. They considered the relatively higher frequency of this condition among Spanish people and commented on the historical relationship between the Arabs and Spaniards during the Middle Ages.