Table 2. [Timing of Achievement of Developmental Milestones in Cohen Syndrome]. - GeneReviews®

Developmental Milestone	Age at Milestone Achievement
Roll over	4-12 months	—	7 months
Sit independently	10-18 months	12 months	11 months
Walk independently	2-5 years	2.5 years	2.5 years
Speak first words	1-5 years	2.5 years	3.2 years
Speak in sentences	5-6 years	5 years	4.2 years

GeneReviews^® [Internet].

Adam MP, Feldman J, Mirzaa GM, et al., editors.

Seattle (WA): University of Washington, Seattle; 1993-2024.

GeneReviews® chapters are owned by the University of Washington. Permission is hereby granted to reproduce, distribute, and translate copies of content materials for noncommercial research purposes only, provided that (i) credit for source (http://www.genereviews.org/) and copyright (© 1993-2024 University of Washington) are included with each copy; (ii) a link to the original material is provided whenever the material is published elsewhere on the Web; and (iii) reproducers, distributors, and/or translators comply with the GeneReviews® Copyright Notice and Usage Disclaimer. No further modifications are allowed. For clarity, excerpts of GeneReviews chapters for use in lab reports and clinic notes are a permitted use.

For more information, see the GeneReviews® Copyright Notice and Usage Disclaimer.

For questions regarding permissions or whether a specified use is allowed, contact: ude.wu@tssamda.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

Developmental Milestone	Age at Milestone Achievement
Developmental Milestone	Finnish Cohort ¹	English Cohort ²	NCSD (US) Cohort ³
Roll over	4-12 months	—	7 months
Sit independently	10-18 months	12 months	11 months
Walk independently	2-5 years	2.5 years	2.5 years
Speak first words	1-5 years	2.5 years	3.2 years
Speak in sentences	5-6 years	5 years	4.2 years