Characteristic	Range of occurrence (%)
Brachycephaly	63 to 98
Oblique palpebral fissures	70 to 98
Gap between first and second toes	44 to 97
Loose skin on nape of neck	17 to 94
Hyperflexibility	47 to 92
Ear abnormalities (set low, folded, stenotic meatus)	28 to 91
Protruding tongue secondary to small, narrow palate	32 to 89
Flat nasal bridge	57 to 87
Muscular hypotonia	21 to 85
Epicanthal folds	28 to 79
Brushfield spots (ring of iris speckles)	35 to 78
Short fifth finger	51 to 77
In-curved fifth finger	43 to 77
Short broad hands	38 to 75
High arched palate	59 to 74
Single palmar crease	42 to 64
Congenital cardiac defect (about one half are complete atrioventricular canal defects)*	40 to 50
Transient myelodysplasia of the newborn*	About 10
Duodenal atresia*	5 to 8