The corpus callosum is absent or only partially formed in people with acrocallosal syndrome, a rare congenital condition. Along with this, there may be some degree of finger or toe deformities as well as malformations of the head and face. People may exhibit mental and motor retardation. The intensity of the symptoms varies from person to person, and the underlying genetic disorder's etiology is unknown.
The participation of the Acra (fingers and toes) with the corpus callosum, the substantial band of fibers connecting the cerebral hemispheres, is referred to as acrocallosal. The disease has been reported in both boys and girls, but its root cause is unknown.
History
In a 4-year-old kid with postaxial polydactyly, hallux duplication, lack of corpus callosum, macrocephaly, and mental impairment, Schinzel initially described the acrocallosal syndrome (ACS) in 1979. Schinzel and Schimid suggested the term "acrocallosal syndrome" in 1980. Since Schinzel's initial description, ACS has now been mentioned in more than 37 cases.
Acrocallosal Syndrome causes
The acrocallosal syndrome has been linked to mutations in the KIF7 gene. Features of this illness can also be brought on by mutations in the GLI3 gene. However, the signs and symptoms of Greig cephalopolysyndactyly syndrome (also brought on by GLI3 gene mutations) strongly resemble those of acrocallosal syndrome, which is frequently thought of as a severe variant of the illness.
The proteins produced from the KIF7 and GLI3 genes play critical roles in the normal shaping (patterning) of many tissues and organs before birth. The proteins are part of a chemical signaling pathway called Sonic Hedgehog signaling. This pathway is involved in cell growth, cell specialization, and the patterning of structures such as the brain and limbs.
Mutations in either the KIF7 or GLI3 gene are thought to impair Sonic Hedgehog signaling, which has wide-ranging effects on development before birth. The roles of these genes in brain and limb patterning may help explain why mutations lead to agenesis of the corpus callosum, polydactyly, and the other features of the acrocallosal syndrome.
Symptoms
The list of signs and symptoms listed below:
Mental retardation
Seizures
Enlarged head
Widely spaced eyes
Cleft lip
Cleft palate
Duplication of the big toe
Extra fingers
Extra Toes
Hypospadias
Undescended Testes
An inguinal hernia
Bipartite right clavicle
Absent corpus callosum
Congenital brain cysts
Complications of Acrocallosal Syndrome
Complications and sequelae of the Acrocallosal syndrome from the Diseases Database include:
Polydactyly
Corpus callosum hypoplasia
Learning disability
Megencephaly
Diagnosis and test
The diagnosis is usually made or confirmed at birth based upon a thorough clinical examination, identification of characteristic physical findings, and various specialized tests. Such testing may include x-ray studies; advanced imaging techniques, such as computed tomography (CT) scanning or magnetic resonance imaging (MRI); or other studies to help detect or characterize certain malformations that may be associated with the disorder (e.g., agenesis or hypoplasia of the corpus callosum, certain craniofacial abnormalities, polydactyly and syndactyly, etc.).
During CT scanning, a computer and x-rays are used to create a film showing cross-sectional images of internal structures. MRI uses a magnetic field and radio waves to create detailed cross-sectional images of certain organs and tissues.
A thorough cardiac evaluation may also be recommended to detect any heart abnormalities that may be associated with the disorder. Such evaluation may include a thorough clinical examination, during which heart and lung sounds are evaluated through use of a stethoscope, and specialized tests that enable physicians to assess the structure and function of the heart (e.g., x-ray studies, electrocardiography, echocardiography, cardiac catheterization).
Treatment and medications
The treatment of acrocallosal syndrome, Schinzel type is directed toward the specific symptoms that are apparent in each individual. Such treatment may require the coordinated efforts of a team of medical professionals, such as pediatricians; surgeons; physicians who diagnose and treat neurological disorders (neurologists); physicians who specialize in heart disease (cardiologists); physicians who diagnose and treat disorders of the skeleton, joints, muscles, and related tissues (orthopedists); eye specialists; and/or other healthcare professionals.
Specific therapies for individuals with acrocallosal syndrome, Schinzel type are symptomatic and supportive. For those with hydrocephalus, early surgery may be advised to insert a tube (shunt) to drain excess cerebrospinal fluid (CSF) away from the brain and into another part of the body where the CSF can be absorbed.
In some instances, surgery may also be recommended to help correct certain craniofacial malformations, polydactyly and syndactyly, and/or other physical abnormalities potentially associated with the disorder. In addition, for those with congenital heart defects, treatment with certain medications, surgical intervention, and/or other measures may be necessary. The surgical procedures performed will depend upon the severity and location of the anatomical abnormalities, their associated symptoms, and other factors.
Physicians may regularly monitor affected infants and children to help ensure prompt detection and early aggressive treatment of respiratory infections. In addition, in some instances, certain preventive measures may be recommended for those who may be prone to repeat respiratory infections. For affected infants who develop respiratory distress, treatment may include various supportive measures, including appropriate oxygen therapy.
Disease management may also include supportive therapies to help ensure proper caloric intake and nutrition in those with feeding difficulties. In some cases, treatment with certain anticonvulsant medications may also be recommended to help prevent, reduce, or control seizures.
Early intervention may be important to ensure that children with the disorder reach their potential. Special services that may be beneficial include special education, physical therapy, and/or other medical, social, or vocational services.
Genetic counseling will be of benefit for affected individuals and their families. Another treatment for this disorder is symptomatic and supportive.
Acrocallosal Syndrome Prevention
For improved prevention of this hereditary condition, antenatal identification of acrocallosal syndrome-Schinzel type is conceivable.
Additionally, if the patient needs a ventriculoperitoneal shunt, it is preferable to choose a line therapy of HSCR to avoid infection.
The Congenital Anomalies of the Neural Tube Defects Use of Folic Acid to Prevent Other Congenital Anomalies and Neural Tube Defects.
It is feasible to diagnose this genetic condition before conception for improved protection. Any child with polysyndactyly, the absence of the corpus Callosum, mental retardation, and hypotonia should be suspected of having acrocallosal syndrome.
Since ACLS is a milder form of anencephaly, supplementing with folic acid was indicated to prevent ACLS in future pregnancies.