Pathogenic variants in DDX3X have recently been identified to be a relatively common cause of intellectual disability in females. In this study, we describe six female probands, from five unrelated families, with five novel heterozygous variants in DDX3X, and the identification of potential germline mosaicism. Consistent features between this cohort and previously described cases include developmental delay or intellectual disability, growth disturbance and movement disorder. Common facial dysmorphism within the cohort include short palpebral fissures, micrognathia, bulbous nasal tip, protruding ears, high arched palate, thin upper vermillion and smooth philtrum. Novel clinical features identified from this cohort include facial dysmorphisms, perinatal complications, valgus feet deformity, lipoatrophy, dystonic episodes, and cutaneous mastocytosis. This case series attempts to expand the phenotype of the DDX3X syndrome; however, it remains heterogeneous. Description of further cases is required to more accurately identify the significance of novel phenotypes within this cohort.
aUniversity of Newcastle, Callaghan
bHunter Genetics, Waratah, NSW
cGenetic Health Queensland, Brisbane
dMurdoch Children’s Research Institute, Royal Children’s Hospital
eUniversity of Melbourne, Parkville
fJohn Hunter Children’s Hospital, New Lambton Heights
gEpilepsy Research Centre, Austin Health
hWalter and Elisa Hall Institute, Melbourne, Australia
iGenetic Health Service New Zealand-Northern Hub, Auckland, New Zealand
Received 1 May 2019 Accepted 16 May 2019
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Correspondence to Himanshu Goel, Clinical Geneticist, PO Box 84, Waratah, NSW 2298, Australia, Tel: +61-2-49853100; fax: +61-2-49853105; e-mail: Himanshu.Goel@health.nsw.gov.au