13/07/2025
A gene deletion in chromosome 1 means that a small or large segment of DNA—containing one or more genes—has been completely removed or is missing from chromosome 1, which is the largest of the 23 human chromosomes.
Let’s break it down simply:
What is a gene deletion?
• A deletion means a section of genetic material is missing.
• That section could contain one or more genes—instructions the body uses to build proteins and regulate development.
What is chromosome 1?
• Chromosome 1 is the largest human chromosome, holding over 2,000 genes.
• It plays a vital role in brain development, growth, immune function, and organ formation.
What does a deletion in chromosome 1 mean?
It depends where on chromosome 1 the deletion is. Each chromosome has two arms:
• the short arm (called p)
• the long arm (called q)
For example:
– A deletion at 1p36 means part of the short arm is missing, and can cause a well-known condition called 1p36 deletion syndrome (developmental delay, hypotonia, possible seizures)
– A deletion at 1q21.1 is linked with learning differences, coordination issues, sometimes autism or congenital anomalies
How does it affect someone?
The effects depend on:
• Which genes are missing
• How large the deletion is
• Whether it’s inherited or de novo (new in the child)
Common signs can include:
• Developmental delay (motor, speech, cognition)
• Low muscle tone (hypotonia)
• Learning difficulties
• Seizures (in some types)
• Distinct facial features (in some syndromes)
• Heart, vision, or skeletal anomalies (depending on genes involved)
But every child is unique. Some are mildly affected, others more significantly.
Important to know:
• A gene deletion is not caused by something the parent did or didn’t do.
• Most deletions happen spontaneously during egg or s***m formation.
• A child with a deletion may still live a full and meaningful life—with tailored support.
• Therapies like Bowen, OT, speech therapy, and sensory integration can help regulate the nervous system and support function.