Table 1.

Genomic sister-disorders of human growth, development, cognition and behavior, with descriptions of their genetic bases

Syndrome name or description	Primary genomic alteration and genes implicated
Smith–Magenis	Hemizygous deletion of region at 17p11.2 including RAI1 gene; RAI1 mutations (Gropman et al. 2007)
Potocki–Lupski	Duplication of Smith–Magenis region (Potocki et al. 2007)
VCFS region deletion	Deletion of ∼30 genes at 22q11.2, effects from COMT, DGCR2, GNB1L, TBX1, UFD1L, other genes (Gothelf 2007; Meechan et al. 2007)
VCFS region duplication	Duplication of 22q11.2 region (Mukaddes and Herguner 2007)
Williams-syndrome region deletion	Hemizygous deletion of over 25 genes at 7q11.23; effects from CYLN2, GTF2I, GTF2IRD1, LIMK1, other genes (Tassabehji 2003; Gray et al. 2006; Edelmann et al. 2007; Young et al. 2008)
Williams-syndrome region duplication	Duplication of 7q11.23 region (Berg et al. 2007)
Klinefelter	One or more excess X chromosomes; Increased expression of PAR1, PAR2 genes and other non X-inactivated genes (DeLisi et al. 2005; Vawter et al. 2007)
Turner	All or part of X chromosome lost (Sybert and McCauley 2004); haploinsufficiency of PAR1, PAR2 genes and other non X-inactivated genes (Lynn and Davies 2007); neurocognitive phenotype maps to Xp22.3 (Zinn et al. 2007)