The 17q12 recurrent deletion syndrome is characterized by variable combinations of the three following findings: structural or functional abnormalities of the kidney and urinary tract, maturity-onset diabetes of the young type 5 (MODY5), and neurodevelopmental or neuropsychiatric disorders (e.g., developmental delay, intellectual disability, autism spectrum disorder, schizophrenia, anxiety, and bipolar disorder). Using a method of data analysis that avoids ascertainment bias, the authors determined that multicystic kidneys and other structural and functional kidney anomalies occur in 85% to 90% of affected individuals, MODY5 in approximately 40%, and some degree of developmental delay or learning disability in approximately 50%. MODY5 is most often diagnosed before age 25 years (range: age 10-50 years).

Primary ciliary dyskinesia-5 (CILD5) is an autosomal recessive disorder characterized by early onset of a progressive decline in lung function due to an inability to clear mucus and particles from the airways. Affected individuals have recurrent infections of the sinuses, ears, airways, and lungs. Sperm motility is also decreased. Individuals with CILD5 do not have situs inversus (summary by Olbrich et al., 2012). For a general phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia, see CILD1 (244400).

Axial spondylometaphyseal dysplasia (SMDAX) is characterized by postnatal growth failure, including rhizomelic short stature in early childhood that evolves into short trunk in late childhood, and thoracic hypoplasia that may cause mild to moderate respiratory problems in the neonatal period and later susceptibility to airway infection. Impaired visual acuity comes to medical attention in early life and vision rapidly deteriorates. Retinal changes are diagnosed as retinitis pigmentosa or pigmentary retinal degeneration on funduscopic examination and as cone-rod dystrophy on electroretinogram. Radiologic hallmarks include short ribs with flared and cupped anterior ends, mild spondylar dysplasia, lacy iliac crests, and metaphyseal irregularities essentially confined to the proximal femora (summary by Suzuki et al., 2011).

CATSPER-related male infertility results from abnormalities in sperm and can be either CATSPER-related nonsyndromic male infertility (NSMI) or the deafness-infertility syndrome (DIS) when associated with non-progressive prelingual sensorineural hearing loss. Males with NSMI have infertility while females have no symptoms. Males with DIS have both infertility and hearing loss, while females have only hearing loss. Routine semen analysis typically identifies abnormalities in sperm number, morphology, and motility. Otologic examination and audiologic assessment can identify hearing loss.

Primary ciliary dyskinesia is a disorder characterized by chronic respiratory tract infections, abnormally positioned internal organs, and the inability to have children (infertility). The signs and symptoms of this condition are caused by abnormal cilia and flagella. Cilia are microscopic, finger-like projections that stick out from the surface of cells. They are found in the linings of the airway, the reproductive system, and other organs and tissues. Flagella are tail-like structures, similar to cilia, that propel sperm cells forward.\n\nIn the respiratory tract, cilia move back and forth in a coordinated way to move mucus towards the throat. This movement of mucus helps to eliminate fluid, bacteria, and particles from the lungs. Most babies with primary ciliary dyskinesia experience breathing problems at birth, which suggests that cilia play an important role in clearing fetal fluid from the lungs. Beginning in early childhood, affected individuals develop frequent respiratory tract infections. Without properly functioning cilia in the airway, bacteria remain in the respiratory tract and cause infection. People with primary ciliary dyskinesia also have year-round nasal congestion and a chronic cough. Chronic respiratory tract infections can result in a condition called bronchiectasis, which damages the passages, called bronchi, leading from the windpipe to the lungs and can cause life-threatening breathing problems.\n\nSome individuals with primary ciliary dyskinesia have abnormally placed organs within their chest and abdomen. These abnormalities arise early in embryonic development when the differences between the left and right sides of the body are established. About 50 percent of people with primary ciliary dyskinesia have a mirror-image reversal of their internal organs (situs inversus totalis). For example, in these individuals the heart is on the right side of the body instead of on the left. Situs inversus totalis does not cause any apparent health problems. When someone with primary ciliary dyskinesia has situs inversus totalis, they are often said to have Kartagener syndrome.\n\nApproximately 12 percent of people with primary ciliary dyskinesia have a condition known as heterotaxy syndrome or situs ambiguus, which is characterized by abnormalities of the heart, liver, intestines, or spleen. These organs may be structurally abnormal or improperly positioned. In addition, affected individuals may lack a spleen (asplenia) or have multiple spleens (polysplenia). Heterotaxy syndrome results from problems establishing the left and right sides of the body during embryonic development. The severity of heterotaxy varies widely among affected individuals.\n\nPrimary ciliary dyskinesia can also lead to infertility. Vigorous movements of the flagella are necessary to propel the sperm cells forward to the female egg cell. Because their sperm do not move properly, males with primary ciliary dyskinesia are usually unable to father children. Infertility occurs in some affected females and is likely due to abnormal cilia in the fallopian tubes.\n\nAnother feature of primary ciliary dyskinesia is recurrent ear infections (otitis media), especially in young children. Otitis media can lead to permanent hearing loss if untreated. The ear infections are likely related to abnormal cilia within the inner ear.\n\nRarely, individuals with primary ciliary dyskinesia have an accumulation of fluid in the brain (hydrocephalus), likely due to abnormal cilia in the brain.

Rarely, individuals with primary ciliary dyskinesia have an accumulation of fluid in the brain (hydrocephalus), likely due to abnormal cilia in the brain.\n\nAnother feature of primary ciliary dyskinesia is recurrent ear infections (otitis media), especially in young children. Otitis media can lead to permanent hearing loss if untreated. The ear infections are likely related to abnormal cilia within the inner ear.\n\nPrimary ciliary dyskinesia can also lead to infertility. Vigorous movements of the flagella are necessary to propel the sperm cells forward to the female egg cell. Because their sperm do not move properly, males with primary ciliary dyskinesia are usually unable to father children. Infertility occurs in some affected females and is likely due to abnormal cilia in the fallopian tubes.\n\nApproximately 12 percent of people with primary ciliary dyskinesia have a condition known as heterotaxy syndrome or situs ambiguus, which is characterized by abnormalities of the heart, liver, intestines, or spleen. These organs may be structurally abnormal or improperly positioned. In addition, affected individuals may lack a spleen (asplenia) or have multiple spleens (polysplenia). Heterotaxy syndrome results from problems establishing the left and right sides of the body during embryonic development. The severity of heterotaxy varies widely among affected individuals.\n\nSome individuals with primary ciliary dyskinesia have abnormally placed organs within their chest and abdomen. These abnormalities arise early in embryonic development when the differences between the left and right sides of the body are established. About 50 percent of people with primary ciliary dyskinesia have a mirror-image reversal of their internal organs (situs inversus totalis). For example, in these individuals the heart is on the right side of the body instead of on the left. Situs inversus totalis does not cause any apparent health problems. When someone with primary ciliary dyskinesia has situs inversus totalis, they are often said to have Kartagener syndrome.\n\nIn the respiratory tract, cilia move back and forth in a coordinated way to move mucus towards the throat. This movement of mucus helps to eliminate fluid, bacteria, and particles from the lungs. Most babies with primary ciliary dyskinesia experience breathing problems at birth, which suggests that cilia play an important role in clearing fetal fluid from the lungs. Beginning in early childhood, affected individuals develop frequent respiratory tract infections. Without properly functioning cilia in the airway, bacteria remain in the respiratory tract and cause infection. People with primary ciliary dyskinesia also have year-round nasal congestion and a chronic cough. Chronic respiratory tract infections can result in a condition called bronchiectasis, which damages the passages, called bronchi, leading from the windpipe to the lungs and can cause life-threatening breathing problems.\n\nPrimary ciliary dyskinesia is a disorder characterized by chronic respiratory tract infections, abnormally positioned internal organs, and the inability to have children (infertility). The signs and symptoms of this condition are caused by abnormal cilia and flagella. Cilia are microscopic, finger-like projections that stick out from the surface of cells. They are found in the linings of the airway, the reproductive system, and other organs and tissues. Flagella are tail-like structures, similar to cilia, that propel sperm cells forward.

CATSPER-related male infertility results from abnormalities in sperm and can be either CATSPER-related nonsyndromic male infertility (NSMI) or the deafness-infertility syndrome (DIS) when associated with non-progressive prelingual sensorineural hearing loss. Males with NSMI have infertility while females have no symptoms. Males with DIS have both infertility and hearing loss, while females have only hearing loss. Routine semen analysis typically identifies abnormalities in sperm number, morphology, and motility. Otologic examination and audiologic assessment can identify hearing loss.

Primary ciliary dyskinesia-14 (CILD14) is an autosomal recessive disorder characterized by recurrent respiratory infections associated with defects in ciliary inner dynein arms and axonemal disorganization (Merveille et al., 2011). For a general phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia, see CILD1 (244400).

Spermatogenic failure-10 (SPGF10) is associated with a defective annulus, a ring structure that demarcates the midpiece and the principal piece of the sperm tail. The firm attachment of the annulus to the flagellar membrane suggests that it may supply mechanical support and prevent displacement of the caudal mitochondrial helix (summary by Kuo et al., 2012). For a discussion of phenotypic and genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Any azoospermia in which the cause of the disease is a mutation in the KLHL10 gene.

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.

Spermatogenic failure-16 (SPGF16) is characterized by acephalic spermatozoa causing male infertility. Semen from affected men consistently shows nearly 100% abnormally shaped spermatozoa, mostly made up of headless tails, with a small proportion of intact spermatozoa with an abnormal head-tail junction, as well as a few tailless heads. Ultrastructurally, the anomaly involves absence of the implantation fossa and basal plate between the sperm head and the tail (summary by Zhu et al., 2016). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-18 (SPGF18) is a form of male infertility caused by multiple morphologic abnormalities of the sperm flagella (Ben Khelifa et al., 2014). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-19 (SPGF19) is characterized by multiple morphologic abnormalities of the flagella (MMAF), including absent, short, coiled, bent, and irregular-caliber flagella (Tang et al., 2017). For a general phenotypic description and a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-21 (SPGF21) is characterized by acephalic spermatozoa causing male infertility (Li et al., 2017). For a general phenotypic description and a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Y chromosome infertility is characterized by azoospermia (absence of sperm), severe oligozoospermia (<1 x 106 sperm/mL semen), moderate oligozoospermia (1-5 x 106 sperm/mL semen), or mild oligozoospermia (5-20 x 106 sperm/mL semen). Males with Y chromosome infertility usually have no obvious symptoms, although physical examination may reveal small testes.

Spermatogenic failure-24 (SPGF24) is characterized by multiple morphologic abnormalities of the flagella (MMAF), including absent, short, coiled, bent, and irregular-caliber flagella. Malformations of the sperm head have also been observed. In addition, patients exhibit very low sperm concentrations and total sperm counts per ejaculate (Dong et al., 2018). For a general phenotypic description and a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-27 (SPGF27) is characterized by infertility due to multiple morphologic abnormalities of the sperm flagella (MMAF), a phenotype also designated as 'dysplasia of the fibrous sheath,' 'short tails,' or 'stump tails.' Spermatozoa in the ejaculate exhibit short, irregular, coiled, or absent flagella. Ultrastructural analysis shows loss of the central pair of microtubules, loss of the inner dynein arms, and peripheral doublet disorganization (Lores et al., 2018). For a discussion of the phenotypic and genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

In spermatogenic failure-3 (SPGF3), primary infertility is associated with nonobstructive asthenozoospermia (Dirami et al., 2013). For a discussion of phenotypic and genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Retinitis pigmentosa-82 with or without situs inversus (RP82) is an autosomal recessive form of retinal degeneration characterized by initial loss of rod photoreceptors, resulting in impaired night vision followed by progressive visual field constriction as both rod and cone photoreceptors die. Some affected individuals have situs inversus (Davidson et al., 2013; Audo et al., 2017). Male patients with infertility due to reduced or absent sperm motility have been reported; female fertility appears to be unaffected (Moye et al., 2019).

Spermatogenic failure-33 (SPGF33) is characterized by multiple morphologic abnormalities of the flagella (MMAF), resulting in immotile spermatozoa and infertility. Short and irregular-caliber flagella are primarily observed, as well as absent and coiled flagella, and abnormalities of the acrosome, head, and base are also present (Kherraf et al., 2018). For a general phenotypic description and a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-34 (SPGF34) is characterized by multiple morphologic abnormalities of the flagella (MMAF), resulting in immotile spermatozoa and infertility. Irregular-caliber, short, and coiled flagella are primarily observed, as well as absent flagella, and abnormalities of the axoneme are also present (Martinez et al., 2018). For a general phenotypic description and a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-37 (SPGF37) is characterized by primary male infertility with asthenoteratozoospermia. Spermatozoa exhibit severely reduced motility due to multiple morphologic abnormalities of the flagella (MMAF), primarily consisting of short or absent flagella. Neck defects at the head-tail junction are frequently seen (Liu et al., 2019). For a general description and a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-38 (SPGF38) is characterized by primary infertility and asthenoteratozoospermia due to multiple morphologic abnormalities of the flagella (MMAF). Spermatozoa show total sperm motility below 10% and exhibit morphologic anomalies including short, absent, coiled, bent, or irregular-caliber flagella (Coutton et al., 2019). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-39 (SPGF39) is characterized by infertility due to asthenozoospermia. In some patients, spermatozoa exhibit multiple morphologic anomalies of the sperm flagellum (MMAF), including short, absent, irregularly shaped, and coiled flagella. Abnormalities of the sperm head and midpiece have also been observed, and ultrastructural analysis shows a lack of the outer dynein arms (ODAs) in sperm cells. In other patients, sperm do not exhibit MMAF, and ultrastructural analysis shows that many flagella lack 1 or more of microtubule doublets (MTDs) 4 to 7 at the principal piece or end piece; however, ODAs are present at the remaining MTDs (Whitfield et al., 2019; Zhang et al., 2020). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-42 (SPGF42) is characterized by infertility and spermatozoa with almost no progressive motility due to multiple morphologic abnormalities of the flagella (MMAF), including short, absent, coiled, irregular-caliber, and/or bent flagella. Some spermatozoa also show abnormalities of the head, acrosome, midpiece, or endpiece (Lores et al., 2019; Liu et al., 2019). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

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).

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).

Spermatogenic failure-45 (SPGF45) is characterized by male infertility due to severe teratozoospermia. Sperm in affected men exhibit multiple morphologic abnormalities of the flagella (MMAF), including flagella that are short, absent, coiled, angulated, and/or of irregular caliber; some sperm also show abnormalities of the head. Ultrastructural analysis shows severe disruption of the axonemal complex and mitochondrial sheath (Li et al., 2019). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-46 (SPGF46) is characterized by male infertility due to asthenoteratozoospermia. Sperm of affected men exhibit multiple morphologic abnormalities of the flagella (MMAF), including flagella that are absent, short, coiled, angulated, and/or of irregular caliber. Ultrastructural analysis shows disorganization of axonemal and periaxonemal structures (Liu et al., 2020). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-49 (SPGF49) is characterized by male infertility due to multiple morphologic abnormalities of the sperm flagella (MMAF), primarily coiled and short flagella, with markedly reduced or no progressive motility (He et al., 2020). For a discussion of genetic heterogeneity of spermatogenic failure, see 258150.

X-linked spermatogenic failure-3 (SPGFX3) is characterized by male infertility due to multiple morphologic abnormalities of the flagella (MMAF). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-51 (SPGF51) is characterized by male infertility due to severe asthenoteratozoospermia. Patients exhibit multiple morphologic abnormalities of the flagella (MMAF), including absent, short, bent, coiled, and irregular-caliber tails, resulting in severely reduced to absent motility. Abnormalities of the sperm head, base, and acrosome have also been observed (Martinez et al., 2020). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-54 (SPGF54) is characterized by male infertility due to oligoteratoasthenozoospermia, with markedly reduced sperm counts and severely reduced or absent sperm motility (Arafat et al., 2021). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-55 (SPGF55) is characterized by male infertility due to asthenozoospermia, with severely reduced sperm motility (Xu et al., 2018). For a general phenotypic description and discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Primary ciliary dyskinesia-46 (CILD46) is characterized by recurrent sinus and respiratory infections, with reduced pulmonary function and uncoordinated beating of respiratory cilia. No situs abnormalities have been observed (Edelbusch et al., 2017). For a general phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia, see CILD1 (244400).

Spermatogenic failure-56 (SPGF56) is characterized by male infertility due to multiple morphologic abnormalities of the flagella (MMAF), resulting in severely reduced sperm motility (Tu et al., 2021). For a general phenotypic description and discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-65 (SPGF65) is characterized by male infertility due to asthenoteratozoospermia. Progressive sperm motility is severely reduced or absent, and patients exhibit multiple morphologic abnormalities of the flagella (MMAF), including coiled, irregular-caliber, short, and absent flagella. Abnormalities of the flagellar midpiece are also present (Tan et al., 2022). For a general phenotypic description and discussion of genetic heterogeneity of SPGF, see SPGF1 (258150).

Spermatogenic failure-70 (SPGF70) is characterized by male infertility due to azoospermia or sperm immotility and necrozoospermia (Yildirim et al., 2018). Hypospermatogenesis and meiotic arrest have also been observed (Kherraf et al., 2022). For a general phenotypic description and discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-76 (SPGF76) is characterized by male infertility due to oligoasthenoteratozoospermia. Multiple morphologic abnormalities of the flagella (MMAF) have been observed, including short, absent, and irregular caliber flagella. Ultrastructural anomalies include disordered outer dense fibers and abnormal 9+2 microtubular structures (Cong et al., 2022). For a general phenotypic description and discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

Spermatogenic failure-79 (SPGF79) is characterized by male infertility due to an abnormal acrosome reaction and impaired membrane potential after capacitation. Some patients exhibit asthenoteratozoospermia, with defective acrosome formation and mitochondrial sheath assembly, and reduced progressive motility (Lv et al., 2022; Liu et al., 2022). For a general phenotypic description and discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

X-linked spermatogenic failure-5 (SPGFX5) is characterized by male infertility due to asthenoteratozoospermia. Patient sperm shows reduced or absent progressive motility, and multiple morphologic abnormalities of the flagella (MMAF) are observed, including short, coiled, irregular caliber, absent, and/or angulated flagella. Pregnancy may be achieved by intracytoplasmic sperm injection (ICSI) (Liu et al., 2023). For a general phenotypic description and discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

X-linked spermatogenic failure-6 (SPGFX6) is characterized by male infertility due to asthenoteratozoospermia. Patient spermatozoa show reduced progressive motility, and multiple morphologic abnormalities of the flagella (MMAF) are observed, primarily short and coiled flagella. Pregnancy can be achieved by intracytoplasmic sperm injection (ICSI) (Liu et al., 2021). For a general phenotypic description and discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

X-linked spermatogenic failure-7 (SPGFX7) is characterized by male infertility due to significantly reduced sperm concentration and progressive motility, with abnormalities of the head and flagella. Patient sperm show insufficient individualization, excessive residual cytoplasm, and defects in acrosome development (Zhang et al., 2023). For a discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).

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).

Primary ciliary dyskinesia-50 (CILD50) is characterized by chronic sinusitis and bronchitis as well as male infertility. Patient sperm have markedly reduced progressive motility, and multiple morphologic abnormalities of the flagella (MMAF) have been observed. Ultrastructurally, patients exhibit defects or loss of the inner dynein arms of the sperm flagella (Wei et al., 2021; Gao et al., 2022). For a general phenotypic description and discussion of genetic heterogeneity of primary ciliary dyskinesia, see CILD1 (244400).

Spermatogenic failure-84 (SPGF84) is characterized by male infertility due to multiple morphologic abnormalities of the sperm flagella (MMAF), including irregular-caliber, bent, coiled, absent, or short tails, resulting in severely reduced motility. Some patients also have a reduced sperm count (Liu et al., 2021; Hu et al., 2023). For a general phenotypic description and discussion of genetic heterogeneity of SPGF, see SPGF1 (258150).

Primary ciliary dyskinesia-51 (CILD51) is characterized by male infertility due to multiple morphologic abnormalities of the sperm flagella (MMAF), resulting in severely reduced progressive motility. Some men also have a low sperm count. In addition, affected individuals experience chronic rhinosinusitis and bronchitis, and recurrent upper and lower respiratory infections, and some exhibit dextrocardia and/or situs inversus (Guo et al., 2021). For a discussion of genetic heterogeneity of primary ciliary dyskinesia, see CILD1 (244400).

Spermatogenic failure-91 (SPGF91) is characterized by male infertility due to teratozoospermia. Patient sperm show defects of the head, including a misshapen rounded head and detachment of the acrosome, and the sperm fail to attach to the zona pellucida of the egg. Pregnancy can be achieved using intracytoplasmic sperm injection (ICSI) (Oud et al., 2020; Fan et al., 2022). For a general phenotypic description and discussion of genetic heterogeneity of spermatogenic failure, see SPGF1 (258150).