Aicardi syndrome is a rare hereditary disease that is manifested by the absence of the corpus callosum, epileptic seizures and changes in the fundus of the eye. In addition, patients have a delay in mental and physical development and a violation of the structure of the facial bones of the skull.
History
In the 60s of the twentieth century, the French neuropathologist Jean Aicardi described a dozen cases of this pathology. There are earlier references to them in the medical literature, but then they were considered to be manifestations of congenital infection. Seven years after the first publication, the medical community introduced a new nosological entity - Aicardi syndrome.
But research on the disease continued, the number of symptoms expanded, and even new offshoots emerged. For example, Aicardi-Gother syndrome, which is manifested by encephalopathy with calcification of the basal ganglia and leukodystrophy.
Prevalence
Since its official recognition, Aicardi syndrome has been encountered by neurologists about half a thousand times. Most patients lived in Japan and other Asian countries. According to Swiss researchers, the incidence of the disease is 15cases per 100,000 children. Unfortunately, statistics are likely to give underestimated numbers, as most patients remain unexamined.
The disease develops in girls. And doctors suggest that this is the cause of most cases of psychophysiological retardation and infantile spasms.
Genetics
Aicardi syndrome is a sex-linked disease, the defective gene is located on the X chromosome. Three cases have been reported in which boys with Klinefelter's syndrome had similar symptoms. For male children with a normal XY genotype, this disease is fatal.
All cases of this disease are the result of sporadic mutations. That is, before that, no cases of Aicardi syndrome were found in the proband's family. Passing the defective gene from mother to daughter is unlikely. The risk that a second child will be born with this pathology is very small and amounts to less than one percent.
If we apply the laws of Mendel, then the following options are possible for spouses who already have one offspring with this disease:
- stillborn boy;
- he althy girl (33%);
- he althy boy (33%);
- sick girl (33%).
The causes of the disease are currently unknown, research is ongoing.
Pathology
Scientists and doctors resort to different methods to establish Aicardi syndrome. Photo of the brain by magneticresonant tomography is one of the most common, but it is possible to see the whole picture only at autopsy. During the study of the brain, multiple anomalies in the development of the neural tube can be detected:
- complete or partial absence of the corpus callosum;
- changing the position of the cerebral cortex;
- abnormal positions of convolutions;
- cysts with serous contents.
Research under a microscope reveals abnormalities in the cellular structure of the affected areas. There are also characteristic changes in the fundus, such as thinning of tissues, a decrease in the number of vessels and pigment, but at the same time, the growth of cones and rods.
Clinic
What do children with Aicardi syndrome look like? The symptoms are initially quite non-specific, because babies are born at term, through the natural birth canal and look he althy. Up to three months, newborns develop without clinical manifestations, then epileptic seizures appear. They are presented in the form of retropulsive symmetrical serial tonic-clonic convulsions of the extremities. In the overwhelming majority of cases, infantile spasms of the flexor muscles also join this. In rare cases, the onset of the disease occurs in the first month of life. Epileptic seizures are not stopped by medication.
In the neurological status of such children, there is a decrease in the size of the skull, a decrease in muscle tone, but at the same time one-sided disinhibition of reflexes or, conversely, paresis and paralysis. In addition, half of the patients have anomalies in the development of the skeleton:vertebral agenesis or absence of ribs. This leads to pronounced scoliotic changes in posture.
Diagnosis
Currently, there are no reliable tests that will help identify Aicardi syndrome. Genetic diagnosis at the prenatal stage is not possible, since the gene responsible for the development of this disease has not yet been identified.
A neurologist may order tests that will look for specific symptoms. These include:
- inspection;
- ophthalmoscopy;
- electroencephalography;
- magnetic resonance imaging;
- X-ray of the spine.
This allows you to detect the absence of the corpus callosum and the violation of the symmetry of the cerebral hemispheres, the presence of cysts.
