Familial 22q11.2 duplication: a three-generation family with a 3-Mb duplication and a familial 1.5-Mb duplication

We report two familial cases of 22q11.2 duplication detected using multiplex ligation-dependent probe amplification (MLPA). In the first case, eight individuals from a three-generation family were found to carry a 3-Mb 22q11.2 duplication. The individuals carrying the duplication show phenotypic variation. This phenotypic variation includes heart defect (1 in 8 individuals, 1/8), submucous cleft palate (2/8), intellectual disability (2/8), speech delay (2/8), behaviour problems (3/8) and brachydactyly (3/8). In the second case, a 1.5-Mb 22q11.2 duplication was detected in a neonate and her normal mother. The neonate presented with severe laryngomalacia causing intermittent stridor. Cranial ultrasound showed small subependymal cysts bilaterally. There was no heart defect or cleft palate, her chest X ray and renal ultrasound were normal. Review at 2 months of age revealed normal growth and development. Our findings broaden the understanding of 22q11.2 duplication syndrome and demonstrate that MLPA is sensitive for detection and sizing of 22q11.2 microduplications.