These findings reveal several cellular defects in cells carrying the PHC1 mutation and highlight the role of chromatin remodeling in the pathogenesis of PM.
Microcephalin 1 (MCPH1) gene, initially identified as an hTERT repressor, result in two autosomal recessive disorders: primary microcephaly and premature chromosome condensation syndrome.
Microcephalin (MCPH1) and Abnormal spindle-like microcephaly associated (ASPM) are genes mutated in primary microcephaly, a human neurodevelopmental disorder.
Microcephalin (MCPH1) is identified as being responsible for the neurodevelopmental disorder primary microcephaly type 1, which is characterized by a smaller-than-normal brain size and mental retardation.
We previously mapped the MCPH1 locus, for primary microcephaly, to chromosome 8p23, and here we report that a gene within this interval, encoding a BRCA1 C-terminal domain-containing protein, is mutated in MCPH1 families sharing an ancestral 8p23 haplotype.
We thus expand the clinical spectrum of ASPM mutations by showing that they can occur in patients with seizures and that the history of seizures alone should not necessarily preclude the diagnosis of primary microcephaly.
Our observation adds to the mutation spectrum of ASPM in primary microcephaly, and is to our knowledge the second example of a constitutional, reciprocal translocation responsible for a bona fide autosomal recessive phenotype.
In addition, using patient-specific induced pluripotent stem cells (iPSCs) with dysfunction of the Aspm gene from a primary microcephaly patient, we demonstrate neurogenesis defects result in defective neuronal activity in patient organoids, suggesting a new strategy to study human developmental diseases in central nerve system.