Report on 3 patients with 12p duplication including GRIN2B

Area of Science:

• Genetics
• Human Genetics
• Chromosomal Abnormalities

Background:

• The short arm (p) of chromosome 12 duplication is a rare chromosomal abnormality.
• Most cases arise from parental translocations, with few pure 12p duplications reported.
• Limited data exists on inherited pure partial 12p duplications.

Observation:

• Three new patients with pure 12p duplication were identified using cytogenetics, array-CGH, and FISH.
• Patient 1: De novo inverted 12p duplication, presenting with "trisomy 12p syndrome" features.
• Patients 2 & 3: Mother and son with direct 12p12.3p13.1 duplication, showing milder phenotypes.

Findings:

• Characterization of a de novo inverted 12p duplication associated with developmental delays and craniofacial abnormalities.
• Identification of a familial direct 12p12.3p13.1 duplication with moderate developmental delays, dysmorphic features, behavioral issues, and obesity.
• Detailed genotypic and phenotypic data for three distinct 12p duplication cases.

Implications:

• This study contributes valuable genotype/phenotype correlation data for trisomy 12p.
• Highlights the phenotypic variability within 12p duplication syndromes.
• Enhances understanding of rare chromosomal abnormalities and their clinical manifestations.