Speech and language abilities of children with the familial form of 22q11.2 deletion syndrome

Abstract

The 22q11.2 Deletion Syndrome (22q11.2DS), which encompasses Shprintzen syndrome, DiGeorge and velocardiofacial syndrome, is the most common microdeletion syndrome in humans with an estimated incidence of approximately 1/4000 per live births. After Down syndrome, it is the second most common genetic syndrome associated with congenital heart malformations. The mode of inheritance of the 22q11.2DS is autosomal dominant. In approximately 72 - 94% of the cases the deletion has occurred de novo, while in 6 to 28% of patients deletion was inherited from a parent. As a part of a multidisciplinary study we examined the speech and language abilities of members of two families with inherited form of 22q11.2DS. The presence of 22q11.2 microdeletion was revealed by fluorescence in situ hybridization (FISH) and/or multiplex ligation-dependent probe amplification (MLPA). In one family we detected 1.5 Mb 22q11.2 microdeletion, while in the other family we found 3Mb microdeletion. Patients from both families showed delays in cognitive, socio-emotional, speech and language development. Furthermore, we found considerable variability in the phenotypic characteristics of 22q11.2DS and the degree of speech-language pathology not only between different families with 22q11.2 deletion, but also among members of the same family. In addition, we detected no correlation between the phenotype and the size of 22q11.2 microdeletion.