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[Familial agenesis of the corpus callosum: a new form]
M Castro-Gago1, A Rodriguez-Nuñez, J Eiris
1Departamento de Pediatria, Hospital General de Galicia, Clinico Universitario, Santiago de Compostela, España.
Insights
This study describes a familial form of agenesis of the corpus callosum (ACC) with severe developmental defects. The findings suggest a potential new autosomal recessive genetic disorder causing ACC and associated neurological abnormalities.
Area of Science:
- Neuroscience
- Genetics
- Developmental Biology
Background:
- Agenesis of the corpus callosum (ACC) is a congenital disorder often linked with other brain malformations.
- Familial cases of ACC are rare, and their genetic basis is not fully understood.
Observation:
- Three siblings presented with severe developmental retardation, microcephaly, hypotonia, seizures, optic atrophy, and abnormal EEG/imaging findings.
- Case 1: 6-year-old girl with IQ 15, died at 12. Case 2: 15-month-old sister, IQ 20, died at 10. Case 3: Infant brother, diagnosed at birth, hypotonic at 5 months, seizures at 18 months.
Findings:
- All siblings exhibited agenesis of the corpus callosum, grey matter heterotopias, and brain atrophy on CT/MRI scans.
- The clinical presentation and inheritance pattern in these siblings differ from previously reported cases of ACC.
- The observed pattern suggests a distinct genetic etiology for this form of ACC.
Implications:
- These cases may represent a novel autosomal recessive syndrome causing agenesis of the corpus callosum.
- Further research is needed to identify the specific gene mutation responsible for this condition.
- Understanding this new form of ACC can aid in diagnosis, genetic counseling, and potential therapeutic strategies.
Abstract:
BACKGROUND. Agenesis of the corpus callosum is generally associated with other developmental defects of the cerebrum. Some familial cases have been reported. CASES REPORTS Case n. 1. A 6 year-old girl was examined because of developmental retardation, first noted at the age of 3 months. There was no consanguinity but 2 girls, cousins of the father, died at 17 and 18 years with the same clinical presentation. Our patient had seizures at 4 years. At examination, she had microcephaly, dilated unreactive pupils, and generalized hypotonia. Her IQ was 15. Funduscopic examination showed optic atrophy and visual evoked potentials were abnormal. The EEG showed spike-wave discharges and the CT scan showed agenesis of the corpus callosum plus heterotopias of the grey matter and brain atrophy. The child died at 12 years of age. Case n. 2. At 15 month-old girl, sister of case n. 1, had shown developmental retardation since the age of 4 months. She had microcephaly, dilated unreactive pupils, generalized hypotonia. Her IQ was 20. She also had optic atrophy, abnormal visual evoked potentials and a hypsarrhythmic pattern on EEG. The CT scan showed agenesis of corpus callosum plus heterotopias of the grey matter and brain atrophy. She died at the age of 10 years. Case n. 3. This boy, brother of cases 1 and 2, was examined on the first day of life. He had microcephaly and some spike-wave discharges on EEG. The CT scan and MRI showed agenesis of the corpus callosum. He had generalized hypotonia at 5 months with an IQ of 30; he suffered from seizures at 18 months. CONCLUSIONS. This agenesis of the corpus callosum seems to have an autosomal recessive inheritance. The associated developmental defects are different from those previously reported, suggesting that these cases represent a new form of corpus callosum lack.