Patients may present with these features:
- Craniosynostosis
- Skeletal muscle hypotonia
- Intellectual disability
- Dolichocephaly
- Proptosis
- Hypertelorism
- Downslanting palpebral fissures
- Myopia
- High arched and narrow palate
- Retrognathia
- Arachnodactyly
- Camptodactyly
- Scoliosis
- Cervical spine abnormality
- Pectus deformity
- Joint hypermobility
- Joint contractures
- Inguinal hernia
- Mitral valve prolapse
- Aortic dilatation
Patients with a genetic variant affecting amino acid 180 (Thr) display a milder morphological phenotype with a marfanoid habitus and no intellectual disability.