RELAX Pretty much everyone with scoliosis will also have some degree of hypokyphosis. It usually just means a lack of the normal outwards curve in the top part of your spine, so it's flatter than it should be (despite any rib hump).
The sort of hypokyphosis that is a worry is the very, very severe type where your spine actually curves forwards where it should curve back. This would mean that you have a much smaller chest cavity than you ought to, and it would restrict your lungs and possibly impact your heart etc etc.
37 years old, diagnosed with infantile idiopathic scoliosis at 6 months old with curves of 62(T) and 40(L) degrees. Casting and Milwaukee braces until surgery at 10 - ant release/pos fusion T1-T12, halo traction. Post op cast and then TLSO. Further surgery at 18 (ant release/pos fusion extended to L3 to include lumbar curve, costoplasty) and 25 (another costoplasty). Fusion extended to L4 at 33 (XLIF with 4 pedicle screws and two short rods). Pre-op curves: 76(T) and 70(L). Post-op curves: 45(T) and 35(L). Diagnosed with Ehlers-Danlos Syndrome aged 34; scoliosis almost certainly due to this rather than being idiopathic.