Microdeletions at 1q21.1 can cause a number of phenotypic findings but can be challenging to diagnose.

Genes that may be affected: GJA5, GJA8, GJA8


Inheritance: autosomal dominant


Some patients are asymptomatic while others are symptomatic.


Clinical features:

(1) developmental delay including speech

(2) microcephaly

(3) mild dysmorphic facial features (frontal bossing, deep-set eyes, bulbous nose)

(4) eye abnormalities (strabismus, colobomas, microphthalmia, hypermetropia, cataracts)

(5) short stature

(6) behavioral problems (ADHD, autism)

(7) variable cardiac malformations

(8) failure to thrive

(9) variable hypotonia

(10) variable seizures

(11) variable sensorineural deafness

(12) variable malformations in brain and genitourinary tract

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