50 USC 2143 - Alternative forms of annuities

(a) Authority for alternative form of annuity 
The Director shall prescribe regulations under which any participant who has a life-threatening affliction or other critical medical condition may, at the time of retiring under this subchapter (other than under section 2051 of this title), elect annuity benefits under this section instead of any other benefits under this subchapter (including any survivor benefits under this subchapter) based on the service of the participant creditable under this subchapter.
(b) Basis for alternative forms of annuity 
The regulations and alternative forms of annuity shall, to the maximum extent practicable, meet the requirements prescribed in section 8343a of title 5.
(c) Lump-sum credit 
Any lump-sum credit provided pursuant to an election under subsection (a) of this section shall not preclude an individual from receiving other benefits provided under that subsection.
(d) Submission of regulations to congressional intelligence committees 
The Director shall submit the regulations prescribed under subsection (a) of this section to the congressional intelligence committees before the regulations take effect.