Hypohidrotic ectodermal dysplasia (HED) is characterized by hypotrichosis (sparseness of scalp and body hair), hypohidrosis (reduced ability to sweat), and hypodontia (congenital absence of teeth). The cardinal features of classic HED become obvious during childhood. The scalp hair is thin, lightly pigmented, and slow growing. Sweating, although present, is greatly deficient, leading to episodes of hyperthermia until the affected individual or family acquires experience with environmental modifications to control temperature. Only a few abnormally formed teeth erupt, at a later-than-average age. Physical growth and psychomotor development are otherwise within normal limits. Mild HED is characterized by mild manifestations of any or all the characteristic features.

Hypohidrotic ectodermal dysplasia (HED) is characterized by hypotrichosis (sparseness of scalp and body hair), hypohidrosis (reduced ability to sweat), and hypodontia (congenital absence of teeth). The cardinal features of classic HED become obvious during childhood. The scalp hair is thin, lightly pigmented, and slow growing. Sweating, although present, is greatly deficient, leading to episodes of hyperthermia until the affected individual or family acquires experience with environmental modifications to control temperature. Only a few abnormally formed teeth erupt, at a later-than-average age. Physical growth and psychomotor development are otherwise within normal limits. Mild HED is characterized by mild manifestations of any or all the characteristic features.

Primary ciliary dyskinesia-18 (CILD18) is an autosomal recessive disorder characterized by early infantile onset of recurrent sinopulmonary infections due to ciliary dysfunction and impaired airway clearance. Males are infertile and about half of patients have situs inversus. Electron microscopy of cilia shows a defect of the outer and inner dynein arms and impaired ciliary function (summary by Horani et al., 2012).

Primary ciliary dyskinesia-19 (CILD19) is an autosomal recessive ciliopathy characterized by chronic sinopulmonary infections, asthenospermia, and immotile cilia. Respiratory epithelial cells and sperm flagella of affected individuals lack both the inner and outer dynein arms. About 50% of patients have situs inversus (summary by Kott et al., 2012). For a phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia, see 244400.

Primary ciliary dyskinesia-22 (CILD22) is an autosomal recessive disorder caused by defective structure and function of cilia or flagella. Ciliary dysfunction causes respiratory distress in term neonates, impaired mucociliary clearance, chronic cough, sinusitis, bronchiectasis, and male infertility. Defective motility of embryonic nodal cilia leads to situs abnormalities in about 50% of patients. CILD22 is characterized by defects of the inner and outer dynein arms (summary by Zariwala et al., 2013). For a phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia, see CILD1 (244400).

Primary ciliary dyskinesia-26 is an autosomal recessive disorder caused by defective ciliary movement. Affected individuals have neonatal respiratory distress, recurrent upper and lower airway disease, and bronchiectasis. About half of patients show laterality defects, including situs inversus totalis. Respiratory cilia from patients show defects in the inner and outer dynein arms (summary by Austin-Tse et al., 2013). For a general phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia, see 244400.

Primary ciliary dyskinesia-27 is an autosomal recessive disorder caused by defective ciliary movement. Affected individuals have neonatal respiratory distress, recurrent upper and lower airway disease, and bronchiectasis. Respiratory cilia from patients show defects in the inner dynein arms and nexin links. Situs inversus has not been reported in these patients (summary by Austin-Tse et al., 2013). For a general phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia, see 244400.

Primary ciliary dyskinesia-28 (CILD28) is an autosomal recessive disorder caused by defective ciliary movement. Affected individuals have recurrent upper and lower airway disease, bronchiectasis, and decreased fertility. About half of patients show laterality defects, including situs inversus. Respiratory cilia from patients show defects in both the inner and outer dynein arms (summary by Knowles et al., 2013). For a general phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia, see CILD1 (244400).

Primary ciliary dyskinesia-38 is an autosomal recessive disorder characterized by chronic airway disease and recurrent sinopulmonary infections beginning in infancy and caused by defective ciliary function. Affected individuals often have neonatal respiratory distress and may later have infertility. About half of patients have laterality defects due to ciliary dysfunction in early embryonic development (summary by Fassad et al., 2018 and Hoben et al., 2018). For a general phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia, see CILD1 (244400).

DEGCAGS syndrome is an autosomal recessive syndromic neurodevelopmental disorder characterized by global developmental delay, coarse and dysmorphic facial features, and poor growth and feeding apparent from infancy. Affected individuals have variable systemic manifestations often with significant structural defects of the cardiovascular, genitourinary, gastrointestinal, and/or skeletal systems. Additional features may include sensorineural hearing loss, hypotonia, anemia or pancytopenia, and immunodeficiency with recurrent infections. Death in childhood may occur (summary by Bertoli-Avella et al., 2021).