MedGen

Sialidosis is an autosomal recessive disorder characterized by the progressive lysosomal storage of sialylated glycopeptides and oligosaccharides caused by a deficiency of the enzyme neuraminidase. Common to the sialidoses is the accumulation and/or excretion of sialic acid (N-acetylneuraminic acid) covalently linked ('bound') to a variety of oligosaccharides and/or glycoproteins (summary by Lowden and O'Brien, 1979). The sialidoses are distinct from the sialurias in which there is storage and excretion of 'free' sialic acid, rather than 'bound' sialic acid; neuraminidase activity in sialuria is normal or elevated. Salla disease (604369) is a form of 'free' sialic acid disease. Classification Lowden and O'Brien (1979) provided a logical nosology of neuraminidase deficiency into sialidosis type I and type II. Type I is the milder form, also known as the 'normosomatic' type or the cherry red spot-myoclonus syndrome. Sialidosis type II is the more severe form with an earlier onset, and is also known as the 'dysmorphic' type. Type II has been subdivided into juvenile and infantile forms. Other terms for sialidosis type II are mucolipidosis I and lipomucopolysaccharidosis. [from OMIM]

Spermatogenic failure-43 (SPGF43) is characterized by infertility and spermatozoa lacking progressive motility due to multiple morphologic abnormalities of the flagella (MMAF), including short, absent, coiled, irregular-caliber, and/or bent flagella. Most flagella lack the central pair (9+0 configuration) on ultrastructural analysis (Liu et al., 2019; Sha et al., 2019; Liu et al., 2020). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150). [from OMIM]

Spermatogenic failure-44 (SPGF44) is characterized by male infertility due to headless sperm in the ejaculate (Sha et al., 2020). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150). [from OMIM]

Spermatogenic failure-83 (SPGF83) is characterized by male infertility due to asthenozoospermia. Patient sperm are immotile, and exhibit an asymmetric fibrous sheath of the flagella (Wu et al., 2023). Patients with reduced sperm motility due to morphologic abnormalities of the flagella (asthenoteratozoospermia) and patients with reduced sperm counts as well as flagellar defects and reduced or absent motility (oligoasthenoteratozoospermia) have been observed (Sha et al., 2022; Zhang et al., 2024). For a general phenotypic description and discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150). [from OMIM]

Spermatogenic failure-26 (SPGF26) is characterized by acephalic spermatozoa due to breakage that occurs in the midpiece of the sperm (Sha et al., 2018). For a general phenotypic description and discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150). [from OMIM]

Primary ciliary dyskinesia-49 (CILD49) without situs inversus is an autosomal recessive disorder characterized by the onset of recurrent respiratory infections, chronic cough, and bronchiectasis in early childhood due to defective ciliary clearance. Affected males also show infertility due to defective flagellar morphology and function. Nasal nitric oxide (NO) levels are normal and situs abnormalities are not observed (Sha et al., 2020; Biebach et al., 2022). For a discussion of genetic heterogeneity of primary ciliary dyskinesia, see CILD1 (244400). [from OMIM]

Spermatogenic failure-89 (SPGF89) is characterized by male infertility due to severely reduced progressive motility of sperm (Sha et al., 2023). For a general phenotypic description and discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150). [from OMIM]