An extremely rare autosomal recessive gastroenterological disorder reported in three families so far characterized by meconium ileus without any further stigmata of cystic fibrosis including pulmonary or pancreatic manifestations. Two of the reported patients developed chronic diarrhea in infancy. Homozygous mutations in the GUCY2C gene (12p12) leading to marked reduction or absence of enzymatic activity of guanylate cyclase 2C were found in the affected patients. The disease was reported to show partial penetrance.

Primary ciliary dyskinesia-44 (CILD44) is an autosomal recessive disorder characterized by recurrent sinopulmonary infections resulting from defective mucociliary clearance. Affected individuals have onset of symptoms in infancy or early childhood, and the repetitive nature of the disorder results in bronchiectasis. Although respiratory epithelial cell motile cilia are shorter than normal and overall ciliary motion is decreased, nasal nitric oxide, radial ciliary structure, and ciliary beat frequency are normal. In addition, patients do not have situs inversus (summary by Chivukula et al., 2020). For a phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia, see CILD1 (244400).