The 15q11.2 BP1-BP2 microdeletion syndrome: a review

Area of Science:

• Genetics
• Neuroscience
• Developmental Biology

Background:

• The 15q11.2 BP1-BP2 microdeletion is an increasingly recognized genetic syndrome.
• It involves four specific genes: TUBGCP5, CYFIP1, NIPA1, and NIPA2.
• Prevalence ranges from 0.57%-1.27% in patients undergoing microarray analysis, a significant increase over controls.

Purpose of the Study:

• To review and categorize the clinical features associated with the 15q11.2 BP1-BP2 microdeletion.
• To understand the spectrum of neurodevelopmental, behavioral, and physical manifestations.
• To explore the genetic mechanisms and penetrance of this microdeletion syndrome.

Main Methods:

• Review of clinical data from approximately 200 individuals with the 15q11.2 BP1-BP2 microdeletion.
• Grouping of observed clinical features into five main categories.
• Analysis of prevalence and comparison with control groups.

Main Results:

• Common features include developmental delay (73%), speech delay (67%), dysmorphic ears (46%), palatal anomalies (46%), learning difficulties (writing 60%, reading 57%), memory problems (60%), and verbal IQ ≤75 (50%).
• Behavioral issues (55%) and abnormal brain imaging (43%) were also frequently noted.
• Less common but significant findings include seizures (26%), autism spectrum disorder (27%), ADHD (35%), schizophrenia (20%), and motor delay (42%).

Conclusions:

• The 15q11.2 BP1-BP2 microdeletion is associated with a range of neurodevelopmental, behavioral, and mild dysmorphic features.
• Despite shared biological pathways, the deletion exhibits incomplete penetrance and variable expressivity.
• This highlights the complex relationship between genomic imbalances and clinical presentation.