Microdeletion at 9q34.3 is associated with Kleefstra Syndrome.

Chromosome defect: 9q34.3

Gene affected: EHMT1 (Euchromatin Histone Methyl Transferase 1)


Clinical features:

(1) intellectual disability with autistic-like features

(2) childhood hypotonia

(3) facial features (hypertelorism, epicanthal folds, broad nasal bridge, anteverted nares, short neck)

(4) expressive speech delay with little speech development

(5) variable cardiac malformations with or without pulmonary hypertension

(6) variable genitourinary malformations

(7) severe respiratory infections

(8) seizures

(9) psychiatric disorders

(10) extreme apathy or catatonic-like features after puberty

(11) variable microcephaly

(12) obstructive sleep apnea

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