The smallest de novo 20q11.2 microdeletion causing intellectual disability and dysmorphic features

Area of Science:

• Genetics
• Developmental Biology
• Clinical Medicine

Background:

• 20q11.2 microdeletion is a rare chromosomal aberration associated with intellectual disability, motor delays, feeding issues, and facial dysmorphism.
• Understanding the phenotypic spectrum and genetic underpinnings of microdeletions is crucial for diagnosis and management.

Purpose of the Study:

• To report a case of 20q11.2 microdeletion in a young child.
• To characterize the clinical features and the size of the deleted region.
• To contribute to the understanding of genotype-phenotype correlations in 20q11.2 microdeletions.

Main Methods:

• Array-based comparative genomic hybridization (aCGH) was used to identify the microdeletion.
• Clinical evaluation of the patient, including developmental assessments and phenotypic description.

Main Results:

• A 2-year-and-6-month-old Japanese girl presented with intellectual disability, motor developmental delay, and distinctive facial features.
• The patient had a 1.2 Mb microdeletion at the 20q11.2 chromosomal region.
• Notably, the patient did not exhibit neonatal feeding problems, a common feature in previously reported cases.

Conclusions:

• This case represents the smallest reported 20q11.2 microdeletion, expanding the spectrum of deletions associated with this syndrome.
• The findings highlight the variability in clinical presentation, particularly the absence of feeding problems in some individuals.
• Further research is needed to fully elucidate the genetic and phenotypic landscape of 20q11.2 microdeletions.