Abstract

Kosaki overgrowth syndrome (KOGS) is a rare (27 cases reported by 2017) syndrome caused by mutations in the PDGFRB gene.

History

This condition was first described in Japan in 2011 by Watanabe et al. These authors thought the condition was the Shprintzen-Goldberg syndrome but the patient lacked a mutation in the SKI gene. A second case was described by Takenouchi "et al" in 2015. These authors recognised that this condition was novel and on performing a whole genome sequecing found mutations in the PDGFRB gene. A further 24 cases were reported in 2017 by Gawliński "et al".

Genetics

No inheritance pattern has been described as these mutations appear to have arisen "de novo". This syndrome is due to mutations in a single copy of the PDGFRB gene.

Clinical features

The features of this syndrome affect the face, skin, brain and the body.

Face:

- downslanting palpebral fissures

- pointed chin

- prominent forehead

- proptosis

- thin upper lip

- wide nasal bridge

Skin:

- fragile

- hyperelastic

Brain:

- Low IQ

- Periventricular white matter lesions

Body:

The height, lower-segment, hand, and foot length are all greater than usual.