Complete trisomy 9 is relatively rare compared to the mosaic form.


Clinical features:

(1) growth retardation

(2) developmental delay

(3) hydrocephalus

(4) subarachnoid cysts

(5) Dandy-Walker malformation of the fourth ventricle

(6) cranial malformations (microcephaly, dolicocephaly, prominent occiput, etc)

(7) wide fontanels

(8) micro-ophthalmia or anophthalmia

(9) deep-set eyes

(10) up-slanting and small palpebral fissures

(11) flat, broad bulbous nose

(12) low-set and malrotated ears

(13) micrognathia

(14) cleft lip and/or palate

(15) short and/or webbed neck

(16) cardiac malformations (ASD, VSD, bicsupid pulmonic valve, persistent left superior vena cava, etc)

(17) shortening of long bones

(18) dislocated joints

(19) hypoplastic pelvic bones

(20) abnormals ribs and/or clavicles

(21) small and/or deformed hands and feet

(22) abnormal genitalia

(23) abnormal urinary tract (hydronephrosis, hypoplasia or aplasis, double collecting system, etc)


Affected neonates usually have only a short survival after birth.


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