A very rare, autosomal recessive, complex, polymalformative disease characterized by corpus callosum agenesis or hypoplasia, craniofacial dysmorphism, duplication of the hallux, postaxial polydactyly, and severe mental retardation.
Hallux Duplication, Postaxial Polydactyly, and Absence of Corpus Callosum; Acrocallosal Syndrome.
Described in 1979 by Albert Schinzel, an Austrian cytogeneticist, in Zurich.
A rare condition reported in Austria, Switzerland, and Turkey.
Autosomal recessive (consanguinity frequent).
Mutations in KIF7 located on 15q26.1, a key component of the Sonic hedgehog pathway.
This medical condition is identified by an association of mental retardation, peculiar facies, absence of the corpus callosum, and polydactyly.
Global syndrome constitutes a complex polymalformative disease characterized by macrocephaly, large anterior fontanel, epicanthal folds, prominent occiput, and bulging forehead. Agenesis of corpus callosum, seizures, hyperreflexia, and anencephaly occurs in some cases. Facial deformations can include low-set posteriorly rotated ears, down-slanting palpebral fissures, exotropia, protruding eyeballs, hypertelorism, broad and short nose, anteverted nostrils, short upper lip, and high-arched cleft palate. Skeletal deformations are also observed: postaxial polydactyly of the fingers and toes, bifid terminal phalanges of the thumbs, duplicated halluces, and tapered fingers. Umbilical and inguinal hernia, light curly hair, hypospadias, hypogonadism, and cardiac defects can occur.
Precautions before anesthesia
The airway must be carefully evaluated (clinical, radiography) because of craniofacial anomalies. Cardiac function (clinical, chest radiograph, echocardiography); neurological function (clinical, EEG, CT, MRI) must be obtained. One must ensure that the seizure therapy is optimal (history, clinical, biology).
Direct laryngoscopy and tracheal intubation may be difficult and may require fiberoptic intubation because of malformations. The availability of a laryngeal mask airway is recommended.
Prophylactic antibiotics must be considered in presence of cardiac defect. Avoid cardiodepressive drugs. Antiepileptic treatment should be continued on day of surgery; consider interaction between antiepileptic and anesthetic drugs.
et al: Spectrum of the acrocallosal syndrome. Am J Med Genet
et al: Novel KIF7 mutations extend the phenotypic spectrum of acrocallosal syndrome. J Med Genet
A: Postaxial polydactyly, hallux duplication, absence of the corpus callosum, macrencephaly and severe mental retardation: A new syndrome. Helv Paediatr Acta