Conditions related to loss of or underdeveloped limbs
Be sensitive with regard to any roleplaying aspects that cast dismemberment or loss of appendages as a negative part of the narrative.
Communication may be required with other children within the session to explain concepts about how single conditions do not define children as a whole, but are simply one of many aspects that any unique child inhabits.
Provide assistance where needed AND when prompted, but never assume to provide the assistance in advance. Ask questions in polite tones, with regard to whether or not assistance is desired, and accommodate the player in kind.
The loss of mobility or dexterity from complications in loss of or underdevelopment of limbs can equate to the extension of time needed per turn. Plan for this time accordingly, and balance the need for movement or note taking versus theater of the mind.
Familiarize yourself with the specific assistive technology the player may be using.