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1p36 deletion syndrome

Last revised by Dr Jeremy Jones on 25 Aug 2021

1p36 deletion syndrome, or monosomy 1p36, is a chromosomal abnormality characterized most commonly by a deletion in the distal segment of the short arm of chromosome one 1.

The 1p36 deletion syndrome is present in approximately 1 in 5,000 live births. It is the most common terminal deletion syndrome 2

There is a broad spectrum of variability in the clinical presentation of monosomy 1p36. Some of the neurodevelopmental and physical abnormalities that may be present in 1p36 deletion syndrome are featured below 1,3:

Findings on antenatal ultrasound, such as ventriculomegaly, cardiac malformations, and midface hypoplasia, sometimes associated with intrauterine growth restriction (IUGR), as well as various other anomalies, should prompt suspicion for 1p36 deletion syndrome 5.

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Cases and figures

  • Case 1: Fetal hydrocephalus
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  • Case 2: Intrauterine growth restriction - symmetrical
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