22q11.2 Deletion Syndrome: A Report of Two Cases

Abstract

Introduction: The 22q11 deletion syndrome was first described in 1965 by Dr. Angelo DiGeorge. It is the most common chromosomal microdeletion with a prevalence of 1 in 3,000 to 6,000 live births and approximately 1 in 1,000 fetuses. It is the syndrome most commonly associated with congenital heart defects. Its clinical presentation is variable and affects various systems.

Objective: To describe two cases of DiGeorge syndrome.

Methods: Two pediatric cases with microdeletions on 22q11.2, both females. The first is a 12-year-old with a history of seizures, moderate global developmental delay, weight of 52 kg, height of 149 cm, head circumference of 54 cm, dysmorphic features, and a small ostium secundum atrial septal defect on echocardiogram. The second is an 11-year-old with an unknown medical history, height of 134 cm, weight of 30 kg, head circumference of 52 cm, dysmorphic features, transilluminable submucous palate, joint hypermobility, developmental and behavioral delay, asymptomatic hypocalcemia, and vitamin D deficiency.

Results: The first case had a normal karyotype 46 XX [25], and genomic hybridization revealed a microdeletion on the long arm of chromosome 22, band 11.21 (arr22q11.21[1864050-21463730]x1) with a loss of 2.54 Mb. The second case also had a normal karyotype 46 XX [25] and genomic hybridization revealed a microdeletion on the long arm of chromosome 22, band 11.21 with a loss of 3 Mb (arr22q11.21[18648855-21,800,471]x1).

Discussion and Conclusion: 22q11.2 deletion syndrome has a heterogeneous phenotype; however, there are key characteristics associated with the deletion that allow for its identification, as seen in our cases.