How to display latest child or granchild page of ID 10

[macaela]

Hi
I have query to display all child page of ID 10, but I would also like to display granchildren, gran gran gran children of that page ID 10

this what I have so far
Thank you

'orderby' => 'date', 
'order' => 'DESC', 
'post_parent' => 10, 
'post_type' => 'page', 
'meta_key' => 'extra_menu', 
'meta_value' => 'portfoliomenu', 
'showposts' => $posts));