Table 2.

SHANK3 genetic variation in 401 individuals with Phelan-McDermid syndrome

Genetic variant	N (%)	Mosaic
22q13 deletion including SHANK3	350 (87.3%)
Terminal deletion	340 (97.1%)	11
Simple deletion	70 (20.6%)	1
Unbalanced translocation	41 (12.1%)	1
Ring chromosome 22	29 (8.5%)	2
Other rearrangementsa	6 (1.8%)	1
Unknownb	194 (57.1%)	6
Interstitial deletion	10 (2.9%)	2
SHANK3 sequence variant	51 (12.7%)
Frameshift	40 (78.4%)
Nonsense	5 (9.8%)
Splice site	2 (3.9%)
Missense	4 (7.8%)

^aOther rearrangements in chromosome 22 included 2 satellited chromosomes, 1 pseudodicentric chromosome, 1 unbalanced inversion, and 2 uncharacterized rearrangements

^bPatients with terminal deletions identified by chromosomal microarray but without a karyotype to exclude the presence of a ring chromosome were classified as unknown