Koolen et al reported clinical findings associated with the 17q21.31 microdeletion syndrome. The authors are from multiple institutions in Europe and North America.

The syndrome is associated with a 500 to 650 kb deletion at 17q21.31.


Clinical features:

(1) developmental delay

(2) hypotonia

(3) facial dysmorphism (see below)

(4) friendly behavior/personality

(5) epilepsy

(6) cardiac malformations

(7) genitourinary tract malformations


Facial features:

(1) long face

(2) tubular or pear-shaped nose

(3) bulbous nasal tip

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