Combined immunodeficiency in a 3-year-old boy with 16p11.2 and 20p12.2-11.2 chromosomal duplications

Area of Science:

• Human Genetics
• Immunology
• Pediatrics

Background:

• Genetic microduplications can lead to complex phenotypes.
• Chromosomal abnormalities, particularly on chromosomes 16p11.2 and 20p, are associated with developmental disorders.

Observation:

• A 3-year-old boy presented with congenital cardiac defects, distinct facial features, and combined T-, B-, and NK cell immunodeficiency.
• He was found to have paternally inherited microduplications: 212.85 kb at 16p11.2 and 7.8 Mb at 20p12.2-11.23.

Findings:

• The 7.8 Mb 20p12.2-11.23 microduplication exhibits novel breakpoints, distinct from previously reported cases of partial trisomy 20p.
• This finding helps to refine the critical region associated with trisomy 20p syndrome.

Implications:

• This case highlights the phenotypic variability associated with microduplications and their impact on multiple organ systems.
• The novel breakpoints contribute to a better understanding of the genetic architecture of trisomy 20p syndrome and associated developmental abnormalities.