Periventricular heterotopia in common microdeletion syndromes

Area of Science:

• Neuroscience
• Genetics
• Developmental Biology

Background:

• Periventricular heterotopia (PH) is a neuronal migrational disorder.
• FLNA gene mutations cause a subset of PH cases, but most have unknown genetic causes.
• Chromosomal anomalies co-occurring with PH are often used to identify new PH-related gene loci.

Purpose of the Study:

• To investigate the role of chromosomal microdeletions in patients with periventricular heterotopia.
• To determine if PH in microdeletion syndromes is indicative of underlying monogenic loci.

Main Methods:

• High-resolution genomic microarray analysis was performed on four PH patients.
• Patients presented with three distinct microdeletion syndromes: 1p36 deletion, 22q11 deletion, and an extended 7q11.23 deletion.

Main Results:

• Three patients had conventional deletions at 1p36 and 22q11.
• One patient exhibited a larger-than-typical deletion at 7q11.23 associated with PH.
• PH is rare in these specific microdeletion syndromes, and other non-recurrent chromosomal defects were noted.

Conclusions:

• The co-occurrence of PH with chromosomal deletions suggests PH can be a manifestation of diverse chromosomal imbalances.
• PH associated with chromosomal deletions may not always indicate uncharacterized monogenic loci.
• This challenges the assumption that PH and chromosomal anomalies directly point to new Mendelian forms of PH.