There is no one who specializes in SA/CRS, as it is a rare condition with multiple medical types of treatment. The list of doctors typically seen for treatment of SA/CRS are:
Urologist to address bladder and kidney (sometimes a nephrologist in the case of severe kidney issues)
Orthopedist to address treatment of hips, legs, knees, and feet
Gastroenterologists to address issues of the GI track and bowels
Neurologist to address issues of the spine and spinal cord
Physical Therapist to address mobility skills and wheelchair selection
Genetisist if there are other specific conditions that may be genetic such as Curarino syndrome (genetic factors for SA/CRS specifically are unknown)
Orthotist to construct and fit leg and foot braces
Nutritionist if there are concerns related to diet