Spinal Muscular Atrophy (SMA) is a rare genetic disorder that affects 1 out of 20,000 newborns. But once the disease takes hold, the result is a life-long burden of ill health. But at the end of 2021, a medical insurance negotiation highlighted the dilemmas faced by many sufferers and their families. Here are the stories of two SMA kids - Tiezhu and Ranran.