Neuropsychological and Genetic Studies of Corpus Callosum Abnormalities

Abstract

Summary and Conclusion T he corpus callosum has a major role in everyday behavior.Absence of the corpus callosum is often associated with cognitive deficits, autism, and epilepsy. In patients with agenesis of corpus callosum the cognitive and neurological consequences vary significantly from mild behavioral problems to severe neurological deficits. ACC can as isolated finding on Magnetic resonance Imaging (MRI), or it is associated with large number of brain anomalies. Callosal agenesis in humans has many causes, it can be and isolated finding in completely normal persons but it is commonly related with cortical malformations or other midline defects, and mostly caused by genetic factors, less commonly by vascular, toxic or from antenatal infection. Corpus callosum abnormalities are associated with many recognized genetic syndromes, some with known genes and many others with still unidentified genes. This study included 64 patients referred to the clinical genetics department of the human genetics and genome division at the Medical research centre of excellence. This is a cross sectional and descriptive study that included sixty-four patients with corpus callosum abnormalities. They were selected over two years of the study. The study aimed at identification of various developmental abnormalities of corpus callosum and detection of associating genetic syndromes and chromosomal aberrations among studied patients. Also the study aimed at associating the morphological abnormalities of CC to the intellectual function, behavioral and social skills of patients. In the literature the CC abnormalities are classified according to their morphology into complete agenesis of the corpus callosum ACC, Hypoplastic CC, Hypoplasia with dysplasia and dysplastic CC (Hanna et al., 2011). So we used this classification and applied it to the MRI findings of our patients. We grouped the studied cases according to the results and diagnosis into three groups. First, patients with chromosomal abnormalities and they were eight patients. Second, Patients with Syndromic corpus callosum abnormalities and they were nine patients. Third group, non-syndromic/unclassified group in which final diagnosis was not reached and they were 47 patients. In the first group of patients we had 8 patients with corpus callosum abnormalities and chromosomal aberrations. They were five males and four females. All of them were from non-consanguineous parents except one case. Psychological evaluation of this group showed 2 cases with mild mental retardation (MR), 2 cases with moderate MR and 4 cases with sever MR. The second group of patients was the patients with syndromic corpus callosum abnormalities. They were five males and four females. All of them were from consanguineous parents except one case, which is Soto’s syndrome (AD inheritance). Psychological evaluation of this group showed 4 cases with moderate MR and 5 cases with severe MR. The third group of patients, which is the major group in our series, is non-syndromic/ unclassified (idiopathic) corpus callosum abnormalities. They were 47 cases representing 73.4% of cases. They were 25 males and 22 females. Consanguinity was positive in 25 cases (53.2%). Psychological evaluation showed that 8 cases had profound MR (17%), 10 cases with severe MR (21.3%), 12 cases with moderate MR (25.5%), 11 cases with Mild MR (23.4%), 6