Abstract: Objectives　To explore the clinical characteristics and prognosis of CRYAB gene related fatal infantile fattening myofibrillar myopathy. Methods　The clinical data of two cases admitted to PICU diagnosed as fatal infantile fattening myofibrillar myopathy by genetic test was retrospectively analyzed, and related literature were reviewed. Results　Two male patients presented with rigid muscles and respiratory insufficiency with onset aged at 3 and 8 months old, respectively. Cardiac ultrasound showed normal and serum creatine kinase were elevated in 2 cases. MRI showed thickening of abdominal muscle and thigh muscle, and trunk muscle stiffness was seen. Electromyogram shows muscle tetanus potential. Muscle biopsy of one case revealed myogenic damage. Gene testing in both cases identify homozygous nucleotide variation of c.3G>A in CRYAB gene. DMPK genes test were normal. Blood and urine screening showed no significant abnormalities. Conclusions　CRYAB gene related fatal infantile fattening myofibrillar myopathy is rare and mainly manifested as muscular rigidity leading to dyspnea, which is different from other neuromuscular diseases. Patients with restrictive dyspnea due to muscular rigidity of the trunk should be vigilant and undergo genetic examination and muscle biopsy.

Key words: 　CRYAB genes;　myofibromyosis;　respiratory failure;　αB-crystallin