MedGen

Primary ciliary dyskinesia is a genetically heterogeneous autosomal recessive disorder resulting from loss of function of different parts of the primary ciliary apparatus, most often dynein arms. Kartagener (pronounced KART-agayner) syndrome is characterized by the combination of primary ciliary dyskinesia and situs inversus (270100), and occurs in approximately half of patients with ciliary dyskinesia. Since normal nodal ciliary movement in the embryo is required for normal visceral asymmetry, absence of normal ciliary movement results in a lack of definitive patterning; thus, random chance alone appears to determine whether the viscera take up the normal or reversed left-right position during embryogenesis. This explains why approximately 50% of patients, even within the same family, have situs inversus (Afzelius, 1976; El Zein et al., 2003). Genetic Heterogeneity of Primary Ciliary Dyskinesia Other forms of primary ciliary dyskinesia include CILD2 (606763), caused by mutation in the DNAAF3 gene (614566) on 19q13; CILD3 (608644), caused by mutation in the DNAH5 gene (603335) on 5p15; CILD4 (608646), mapped to 15q13; CILD5 (608647), caused by mutation in the HYDIN gene (610812) on 16q22; CILD6 (610852), caused by mutation in the TXNDC3 gene (607421) on 7p14; CILD7 (611884), caused by mutation in the DNAH11 gene (603339) on 7p15; CILD8 (612274), mapped to 15q24-q25; CILD9 (612444), caused by mutation in the DNAI2 gene (605483) on 17q25; CILD10 (612518), caused by mutation in the DNAAF2 gene (612517) on 14q21; CILD11 (612649), caused by mutation in the RSPH4A gene (612647) on 6q22; CILD12 (612650), caused by mutation in the RSPH9 gene (612648) on 6p21; CILD13 (613193), caused by mutation in the DNAAF1 gene (613190) on 16q24; CILD14 (613807), caused by mutation in the CCDC39 gene (613798) gene on 3q26; CILD15 (613808), caused by mutation in the CCDC40 gene (613799) on 17q25; CILD16 (614017), caused by mutation in the DNAL1 gene (610062) on 14q24; CILD17 (614679), caused by mutation in the CCDC103 gene (614677) on 17q21; CILD18 (614874), caused by mutation in the DNAAF5 gene (614864) on 7p22; CILD19 (614935), caused by mutation in the LRRC6 gene (614930) on 8q24; CILD20 (615067), caused by mutation in the CCDC114 gene (615038) on 19q13; CILD21 (615294), caused by mutation in the DRC1 gene (615288) on 2p23; CILD22 (615444), caused by mutation in the ZMYND10 gene (607070) on 3p21; CILD23 (615451), caused by mutation in the ARMC4 gene (615408) on 10p; CILD24 (615481), caused by mutation in the RSPH1 gene (609314) on 21q22; CILD25 (615482), caused by mutation in the DYX1C1 gene (608706) on 15q21; CILD26 (615500), caused by mutation in the C21ORF59 gene (615494) on 21q22; CILD27 (615504), caused by mutation in the CCDC65 gene (611088) on 12q13; CILD28 (615505), caused by mutation in the SPAG1 gene (603395) on 8q22; CILD29 (615872), caused by mutation in the CCNO gene (607752) on 5q11; CILD30 (616037), caused by mutation in the CCDC151 gene (615956) on 19p13; CILD32 (616481), caused by mutation in the RSPH3 gene (615876) on 6q25; CILD33 (616726), caused by mutation in the GAS8 gene (605178) on 16q24; CILD34 (617091), caused by mutation in the DNAJB13 gene (610263) on 11q13; CILD35 (617092), caused by mutation in the TTC25 gene (617095) on 17q21; CILD36 (300991), caused by mutation in the PIH1D3 gene (300933) on Xq22; CILD37 (617577), caused by mutation in the DNAH1 gene (603332) on 3p21; CILD38 (618063), caused by mutation in the CFAP300 gene (618058) on 11q22; CILD39 (618254), caused by mutation in the LRRC56 gene (618227) on 11p15; CILD40 (618300), caused by mutation in the DNAH9 gene (603330) on 17p12; CILD41 (618449), caused by mutation in the GAS2L2 gene (611398) on 17q12; CILD42 (618695), caused by mutation in the MCIDAS gene (614086) on 5q11; CILD43 (618699), caused by mutation in the FOXJ1 gene (602291) on 17q25; CILD44 (618781), caused by mutation in the NEK10 gene (618726) on 3p24; CILD45 (618801), caused by mutation in the TTC12 gene (610732) on 11q23; CILD46 (619436), caused by mutation in the STK36 gene (607652) on 2q35; CILD47 (619466), caused by mutation in the TP73 gene (601990) on 1p36; CILD48 (620032), caused by mutation in the NME5 gene (603575) on chromosome 5q31; CILD49 (620197), caused by mutation in the CFAP74 gene (620187) on chromosome 1p36; CILD50 (620356), caused by mutation in the DNAH7 gene (610061) on chromosome 2q32; CILD51 (620438), caused by mutation in the BRWD1 gene (617824) on chromosome 21q22; CILD52 (620570), caused by mutation in the DAW1 gene (620279) on chromosome 2q36; and CILD53 (620642), caused by mutation in the CLXN gene (619564) on chromosome 8q11. Ciliary abnormalities have also been reported in association with both X-linked and autosomal forms of retinitis pigmentosa. Mutations in the RPGR gene (312610), which underlie X-linked retinitis pigmentosa (RP3; 300029), are in some instances (e.g., 312610.0016) associated with recurrent respiratory infections indistinguishable from immotile cilia syndrome; see 300455. Afzelius (1979) gave an extensive review of cilia and their disorders. There are also several possibly distinct CILDs described based on the electron microscopic appearance of abnormal cilia, including CILD with transposition of the microtubules (215520), CILD with excessively long cilia (242680), and CILD with defective radial spokes (242670). [from OMIM]

Primary ciliary dyskinesia (PCD; CILD) is an autosomal recessive disorder resulting from loss of normal ciliary function. Kartagener (pronounced KART-agayner) syndrome is characterized by the combination of primary ciliary dyskinesia and situs inversus, and occurs in approximately half of patients with ciliary dyskinesia. Since normal nodal ciliary movement in the embryo is required for normal visceral asymmetry, absence of normal ciliary movement results in a lack of definitive patterning; thus, random chance alone appears to determine whether the viscera take up the normal or reversed left-right position during embryogenesis. This explains why approximately 50% of patients, even within the same family, have situs inversus (summary by Afzelius, 1976; El Zein et al., 2003). For a general phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia and the Kartagener syndrome, see CILD1 (244400). [from OMIM]

Primary ciliary dyskinesia is an autosomal recessive disorder resulting from loss of normal ciliary function. Kartagener (pronounced KART-agayner) syndrome is characterized by the combination of primary ciliary dyskinesia and situs inversus, and occurs in approximately half of patients with ciliary dyskinesia. Since normal nodal ciliary movement in the embryo is required for normal visceral asymmetry, absence of normal ciliary movement results in a lack of definitive patterning; thus, random chance alone appears to determine whether the viscera take up the normal or reversed left-right position during embryogenesis. This explains why approximately 50% of patients, even within the same family, have situs inversus (Afzelius, 1976; El Zein et al., 2003). For a general description and a discussion of genetic heterogeneity of primary ciliary dyskinesia and Kartagener syndrome, see CILD1 (244400). [from OMIM]

Primary ciliary dyskinesia is an autosomal recessive disorder resulting from loss of normal ciliary function. Kartagener (pronounced KART-agayner) syndrome is characterized by the combination of primary ciliary dyskinesia and situs inversus, and occurs in approximately half of patients with ciliary dyskinesia. Since normal nodal ciliary movement in the embryo is required for normal visceral asymmetry, absence of normal ciliary movement results in a lack of definitive patterning; thus, random chance alone appears to determine whether the viscera take up the normal or reversed left-right position during embryogenesis. This explains why approximately 50% of patients, even within the same family, have situs inversus (Afzelius, 1976; El Zein et al., 2003). For a general phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia and the Kartagener syndrome, see CILD1 (244400). [from OMIM]

MHC class II deficiency (MHC2D), also known as bare lymphocyte syndrome type II (BLS type II), is a rare autosomal recessive primary immunodeficiency showing genetic heterogeneity. The disorder is characterized by the loss of expression of MHC class II antigens (HLA-DR, HLA-DQ, and HLA-DP) on antigen-presenting cells (APCs) resulting from mutations in regulatory genes required for proper transcription of the MHC class II genes. Affected individuals present in early infancy with severe recurrent infections (bacteria, viruses, fungi, and protozoa), usually affecting the gastrointestinal and respiratory tracts. Protracted diarrhea and failure to thrive is often present. About 20% of patients develop autoimmune features, mainly cytopenias. Laboratory studies show reduced CD4+ T cell counts with an inverted CD4:CD8 ratio, hypogammaglobulinemia, and abnormal lymphocyte proliferation to foreign antigens. Death in infancy or early childhood often occurs, although some patients may have longer survival. MHC type II deficiency may not detected by newborn screening for T-cell receptor excision circles (TRECs). Bone marrow transplantation may be curative, although complications are common (summary by Hanna and Etzioni, 2014; El Hawary et al., 2019). In HLA class II deficiency, the abnormal expression of HLA molecules has been shown to be secondary to defective synthesis (Lisowska-Grospierre et al., 1985), due in turn to an abnormal transacting regulatory gene located outside the major histocompatibility complex (MHC) (Marcadet et al., 1985; de Preval et al., 1985). The transacting regulatory factor, known as RFX, binds to class II promoters and is defective in hereditary HLA deficiency type II, otherwise known as the 'bare lymphocyte syndrome.' The failure of HLA expression leads to immunodeficiency affecting both cellular and humoral responses to antigens. DeSandro et al. (1999) reviewed the molecular bases of the several forms of MHC deficiency. Genetic Heterogeneity of MHC Class II Deficiency MHC2D2 (620815) is caused by mutation in the RFXANK gene (603200); MHC2D3 (620816) and MHC2D5 (620818) are caused by mutation in the RFX5 gene (601863); and MHC2D4 (620817) is caused by mutation in the RFXAP gene (601861). See also MHC class I deficiency (MHC1D1; 604571). [from OMIM]

Dyggve-Melchior-Clausen disease (DMC) is an autosomal recessive disorder characterized by progressive spondyloepimetaphyseal dysplasia and impaired intellectual development. Short-trunk dwarfism and microcephaly are present, and specific radiologic appearances most likely reflect abnormalities of the growth plates, including platyspondyly with notched end plates, metaphyseal irregularities, laterally displaced capital femoral epiphyses, and small iliac wings with lacy iliac crests (summary by El Ghouzzi et al., 2003). [from OMIM]

Immunodeficiency-124 (IMD124) is an autosomal recessive form of T-/B-/NK+ severe combined immunodeficiency (SCID) characterized by the onset of recurrent infections in infancy or early childhood. Laboratory studies show T- and B-cell lymphopenia, hypogammaglobulinemia with increased IgM, and normal NK cells, usually with progression to bone marrow aplasia and pancytopenia. Many patients have autoimmune cytopenias, such as hemolytic anemia or thrombocytopenia. Affected individuals also have poor growth with microcephaly and may have characteristic dysmorphic facial features. Patient-derived cells show increased sensitivity to ionizing radiation and shortened telomeres associated with premature senescence of hematopoietic stem cells (summary by Carrillo et al., 2017 and El Hawary et al., 2023). For a general phenotypic description and a discussion of genetic heterogeneity of autosomal recessive SCID, see 601457. [from OMIM]

Primary ciliary dyskinesia-34 (CILD34) is an autosomal recessive disorder characterized by childhood onset of recurrent sinopulmonary infections due to impaired ciliary function. Affected males are infertile due to impaired sperm function and viability. Laterality defects have not been observed in this type of CILD (summary by El Khouri et al., 2016). For a general phenotypic description and a discussion of genetic heterogeneity of primary ciliary dyskinesia, see CILD1 (244400). [from OMIM]

El Hayek-Chahrour neurodevelopmental disorder (NEDEHC) is characterized by absent speech, impaired intellectual development, and autism (El Hayek et al., 2020). [from OMIM]

Retinitis pigmentosa (RP), also designated rod-cone dystrophy, is characterized by initial night blindness due to rod dysfunction, with subsequent progressive constriction of visual fields, abnormal color vision, and eventual loss of central vision due to cone photoreceptor involvement (summary by El Shamieh et al., 2014). For a discussion of genetic heterogeneity of retinitis pigmentosa, see 268000. [from OMIM]

MHC class II deficiency-3 (MHC2D3) is a rare autosomal recessive immunodeficiency characterized by the onset of recurrent and persistent infections from birth. Infectious agents include bacteria, viruses, fungi, and protozoa, usually affecting the respiratory and gastrointestinal tract. Laboratory studies show decreased CD4+ T cells, hypogammaglobulinemia, an inverted CD4:CD8 ratio, and absence of MHC type II antigens (HLA-DR, -DQ, and -DP) on the surface of antigen-presenting cells. Most patients die in infancy or early childhood unless they undergo bone marrow transplantation, which can be curative, although complications are common. Rare patients may survive longer, even without bone marrow transplant. MHC class II deficiency may not be detected by newborn T-cell receptor excision circle (TREC) screening (summary by El Hawary et al., 2019; Mousavi Khorshidi et al., 2023). For a discussion of genetic heterogeneity of MHC class II deficiency, see MHC2D1 (209920). [from OMIM]

X-linked intellectual developmental disorder-111 (XLID111) is a neurodevelopmental disorder characterized by different degrees of impaired intellectual development associated with motor, speech, and behavioral impairments (El Chehadeh et al., 2022). [from OMIM]

Neurodevelopmental disorder with speech impairment and with or without seizures (NEDSIS) is a phenotypically heterogeneous neurologic disorder whose severity appears to depend on the functional effect of the CACNA1I mutation. Severely affected individuals present in infancy with profound global developmental delay, hypotonia, delayed or absent walking, absent speech, feeding difficulties, cortical visual impairment, and onset of hyperexcitability and seizures in the first months or years of life. They achieve little or no developmental progress and may be tube-fed. Mutations in these individuals occurred de novo. In contrast, a milder phenotype associated with an inherited mutation has been found in a family with mild to moderate cognitive impairment and mild speech delay, usually without seizures (El Ghaleb et al., 2021). [from OMIM]

Suleiman-El-Hattab syndrome (SULEHS) is an autosomal recessive multisystem developmental disorder characterized by hypotonia and feeding difficulties soon after birth, global developmental delay with impaired intellectual development and poor expressive speech, and a general happy demeanor. There is a distinctive facial appearance with microcephaly, thick arched eyebrows with synophrys, hypertelorism, epicanthal folds, low-set ears, broad nasal bridge, and thin upper lip. Additional more variable features include recurrent respiratory infections, cardiovascular malformations, cryptorchidism, seizures, and distal anomalies of the hands and feet (summary by Suleiman et al., 2019). [from OMIM]