Cystic fibrosis (CF) is a multisystem disease affecting epithelia of the respiratory tract, exocrine pancreas, intestine, hepatobiliary system, and exocrine sweat glands. Morbidities include recurrent sinusitis and bronchitis, progressive obstructive pulmonary disease with bronchiectasis, exocrine pancreatic deficiency and malnutrition, pancreatitis, gastrointestinal manifestations (meconium ileus, rectal prolapse, distal intestinal obstructive syndrome), liver disease, diabetes, male infertility due to hypoplasia or aplasia of the vas deferens, and reduced fertility or infertility in some women. Pulmonary disease is the major cause of morbidity and mortality in CF.

Autosomal recessive myopathy with rigid spine and distal joint contractures (MRRSDC) is characterized by onset of slowly progressive muscle weakness in the first or second decades of life. There is initial involvement of the proximal lower limbs, followed by distal upper and lower limb muscle weakness and atrophy. Other features include joint contractures, rigid spine, and restricted pulmonary function; some patients may have mild cardiac involvement (summary by Kayman-Kurekci et al., 2014).