Takenouchi-Kosaki Syndrome

Clinical Characteristics
Ocular Features: 

The ocular phenotype consists of mild ptosis, synophrys, exotropia, and eversion of the lower eyelids.  One of two reported patients was described as having bilateral retinal dysplasia and a falciform retinal detachment in one eye.  Visual acuity is significantly impaired.

Systemic Features: 

Affected individuals may be of normal birth weight but skeletal growth is subnormal and there is general developmental delay.  Congenial cardiac anomalies such as persistent ductus arteriosus may be present.  Lymphedema has been noted at one year of age and probably persists throughout life.  Protein-losing enteropathy secondary to intestinal lymphangiectasia was present in one individual.  The same patient had pericardial effusion, hydrothorax, and ascites.  Intellectual disability may be severe although there is no evidence of progression.  Neurosensory hearing loss has been described in one patient.

Thrombocytopenia is a consistent finding and has been described as early as one year of age.  Platelet numbers as low as 52,000/microL have been recorded and appear larger than normal. 


Both unrelated female patients reported have heterozygous missense mutations in the CDC42 gene (1p36). 

Treatment Options: 

No treatment has been reported.

Article Title: 


Takenouchi T, Kosaki R, Niizuma T, Hata K, Kosaki K. Macrothrombocytopenia and developmental delay with a de novo CDC42 mutation: Yet another locus for thrombocytopenia and developmental delay. Am J Med Genet A. 2015 Nov;167A(11):2822-5. 

PubMedID: 26386261