Lymphedema-distichiasis syndrome (referred to as LDS in this GeneReview) is characterized by lower-limb lymphedema, and distichiasis (aberrant eyelashes ranging from a full set of extra eyelashes to a single hair). Lymphedema typically appears in late childhood or puberty, is confined to the lower limbs with or without involvement of the external genitalia, and is often asymmetric; severity varies within families. Males develop edema at an earlier age and have more problems with cellulitis than females. Distichiasis, which may be present at birth, is observed in 94% of affected individuals. About 75% of affected individuals have ocular findings including corneal irritation, recurrent conjunctivitis, and photophobia; other common findings include varicose veins and ptosis.

Congenital disorder of glycosylation type IIc (CDG2C) is an autosomal recessive disorder characterized by moderate to severe psychomotor retardation, mild dysmorphism, and impaired neutrophil motility. It is a member of a group of disorders with a defect in the processing of protein-bound glycans. For a general overview of congenital disorders of glycosylation (CDGs), see CDG1A (212065) and CDG2A (212066). Frydman (1996) contended that the neutrophil defect in CDG2C, which has been referred to as 'leukocyte adhesion deficiency type II' (LAD2), is a manifestation of the disorder and that there are no cases of 'primary' LAD II. Etzioni and Harlan (1999) provided a comprehensive review of both leukocyte adhesion deficiency-1 (LAD1; 116920) and LAD2. While the functional neutrophil studies are similar in the 2 LADs, the clinical course is milder in LAD2. Furthermore, patients with LAD2 present other abnormal features, such as growth and mental retardation, which are related to the primary defect in fucose metabolism. Delayed separation of the umbilical cord occurs in LAD1. For a discussion of genetic heterogeneity of LAD, see 116920.

Primary lymphedema is caused by anatomic or functional defects in the lymphatic system, resulting in chronic swelling of body parts. There may be accompanying nail and skin changes, such as nail dysplasia or papillomatosis. Onset is usually at birth or in early childhood but can occur later, and the severity is variable (summary by Gordon et al., 2013 and Balboa-Beltran et al., 2014). Genetic Heterogeneity of Lymphatic Malformation Primary lymphedema is genetically heterogeneous: see also LMPHM2 (611944), which maps to chromosome 6q16.2-q22.1; LMPHM3 (613480), caused by mutation in the GJC2 gene (608803) on chromosome 1q42; LMPHM4 (615907), caused by mutation in the VEGFC gene (601528) on chromosome 4q34; LMPHM5 (153200); LMPHM6 (616843), caused by mutation in the PIEZO1 gene (611184) on chromosome 16q24; LMPHM7 (617300), caused by mutation in the EPHB4 gene (600011) on chromosome 7q22; LMPHM8 (618773), caused by mutation in the CALCRL gene (114190) on chromosome 2q31; LMPHM9 (619319), caused by mutation in the CELSR1 gene (604523) on chromosome 22q13; LMPHM10 (610369), caused by mutation in the ANGPT2 gene (601922) on chromosome 8p23; LMPHM11 (619401), caused by mutation in the TIE1 gene (600222) on chromosome 1p34; LMPHM12 (620014), caused by mutation in the MDFIC gene (614511) on chromosome 7q31; LMPHM13 (620244), caused by mutation in the THSD1 gene (616821) on chromosome 13q14; and LMPHM14 (620602), caused by mutation in the ERG gene (165080) on chromosome 21q22. Lymphedema can also be a feature of syndromic disorders such as lymphedema-distichiasis syndrome (153400), which is caused by mutation in the FOXC2 gene (602402), and various forms of nonimmune hydrops fetalis (NIHF; see 236750).

Chronic granulomatous disease (CGD) is a primary immunodeficiency disorder of phagocytes (neutrophils, monocytes, macrophages, and eosinophils) resulting from impaired killing of bacteria and fungi. CGD is characterized by severe recurrent bacterial and fungal infections and dysregulated inflammatory responses resulting in granuloma formation and other inflammatory disorders such as colitis. Infections typically involve the lung (pneumonia), lymph nodes (lymphadenitis), liver (abscess), bone (osteomyelitis), and skin (abscesses or cellulitis). Granulomas typically involve the genitourinary system (bladder) and gastrointestinal tract (often the pylorus initially, and later the esophagus, jejunum, ileum, cecum, rectum, and perirectal area). Some males with X-linked CGD have McLeod neuroacanthocytosis syndrome as the result of a contiguous gene deletion. While CGD may present anytime from infancy to late adulthood, the vast majority of affected individuals are diagnosed before age five years. Use of antimicrobial prophylaxis and therapy has greatly improved overall survival.

Immunodeficiency-41 is an autosomal recessive complex disorder of immune dysregulation. Affected individuals present in infancy with recurrent viral, fungal, and bacterial infections, lymphadenopathy, and variable autoimmune features, such as autoimmune enteropathy and eczematous skin lesions. Immunologic studies show a defect in T-cell regulation (summary by Goudy et al., 2013).

Phelan-McDermid syndrome is characterized by neonatal hypotonia, absent to severely delayed speech, developmental delay, and minor dysmorphic facial features. Most affected individuals have moderate to profound intellectual disability. Other features include large fleshy hands, dysplastic toenails, and decreased perspiration that results in a tendency to overheat. Normal stature and normal head size distinguishes Phelan-McDermid syndrome from other autosomal chromosome disorders. Behavior characteristics include mouthing or chewing non-food items, decreased perception of pain, and autism spectrum disorder or autistic-like affect and behavior.

Chronic granulomatous disease (CGD) is a primary immunodeficiency disorder of phagocytes (neutrophils, monocytes, macrophages, and eosinophils) resulting from impaired killing of bacteria and fungi. CGD is characterized by severe recurrent bacterial and fungal infections and dysregulated inflammatory responses resulting in granuloma formation and other inflammatory disorders such as colitis. Infections typically involve the lung (pneumonia), lymph nodes (lymphadenitis), liver (abscess), bone (osteomyelitis), and skin (abscesses or cellulitis). Granulomas typically involve the genitourinary system (bladder) and gastrointestinal tract (often the pylorus initially, and later the esophagus, jejunum, ileum, cecum, rectum, and perirectal area). Some males with X-linked CGD have McLeod neuroacanthocytosis syndrome as the result of a contiguous gene deletion. While CGD may present anytime from infancy to late adulthood, the vast majority of affected individuals are diagnosed before age five years. Use of antimicrobial prophylaxis and therapy has greatly improved overall survival.

Chronic granulomatous disease (CGD) is a primary immunodeficiency disorder of phagocytes (neutrophils, monocytes, macrophages, and eosinophils) resulting from impaired killing of bacteria and fungi. CGD is characterized by severe recurrent bacterial and fungal infections and dysregulated inflammatory responses resulting in granuloma formation and other inflammatory disorders such as colitis. Infections typically involve the lung (pneumonia), lymph nodes (lymphadenitis), liver (abscess), bone (osteomyelitis), and skin (abscesses or cellulitis). Granulomas typically involve the genitourinary system (bladder) and gastrointestinal tract (often the pylorus initially, and later the esophagus, jejunum, ileum, cecum, rectum, and perirectal area). Some males with X-linked CGD have McLeod neuroacanthocytosis syndrome as the result of a contiguous gene deletion. While CGD may present anytime from infancy to late adulthood, the vast majority of affected individuals are diagnosed before age five years. Use of antimicrobial prophylaxis and therapy has greatly improved overall survival.

Chronic granulomatous disease (CGD) is a primary immunodeficiency disorder of phagocytes (neutrophils, monocytes, macrophages, and eosinophils) resulting from impaired killing of bacteria and fungi. CGD is characterized by severe recurrent bacterial and fungal infections and dysregulated inflammatory responses resulting in granuloma formation and other inflammatory disorders such as colitis. Infections typically involve the lung (pneumonia), lymph nodes (lymphadenitis), liver (abscess), bone (osteomyelitis), and skin (abscesses or cellulitis). Granulomas typically involve the genitourinary system (bladder) and gastrointestinal tract (often the pylorus initially, and later the esophagus, jejunum, ileum, cecum, rectum, and perirectal area). Some males with X-linked CGD have McLeod neuroacanthocytosis syndrome as the result of a contiguous gene deletion. While CGD may present anytime from infancy to late adulthood, the vast majority of affected individuals are diagnosed before age five years. Use of antimicrobial prophylaxis and therapy has greatly improved overall survival.

Pyogenic sterile arthritis, pyoderma gangrenosum, and acne (PAPA) is a rare autosomal dominant autoinflammatory disease that typically presents with recurrent sterile, erosive arthritis in childhood, occurring spontaneously or after minor trauma, occasionally resulting in significant joint destruction. By puberty, joint symptoms tend to subside and cutaneous symptoms predominate, including pathergy, frequently with abscesses at the sites of injections, severe cystic acne, and recurrent nonhealing sterile ulcers, often diagnosed as pyoderma gangrenosum (summary by Demidowich et al., 2012).

Primary lymphedema with myelodysplasia, also known as Emberger syndrome, is a rare disorder characterized by childhood-onset lymphedema of the lower limbs, with lymphoscintigraphy suggestive of lymphatic vessel hypoplasia, and genital lymphatic abnormalities. Myelodysplasia is usually with monosomy 7. Multiple warts, deafness, and minor anomalies (mild hypotelorism, neck webbing, and slender fingers) may also be present (summary by Mansour et al., 2010).

Autoinflammation, antibody deficiency, and immune dysregulation (APLAID) is an autosomal dominant systemic disorder characterized by recurrent blistering skin lesions with a dense inflammatory infiltrate and variable involvement of other tissues, including joints, the eye, and the gastrointestinal tract. Affected individuals have a mild humoral immune deficiency associated with recurrent sinopulmonary infections, but no evidence of circulating autoantibodies (summary by Zhou et al., 2012).

Activated PI3K-delta syndrome (also known as APDS) is a disorder that impairs the immune system. Individuals with this condition often have low numbers of white blood cells (lymphopenia), particularly B cells and T cells. Normally, these cells recognize and attack foreign invaders, such as viruses and bacteria, to prevent infection. The severity of activated PI3K-delta syndrome varies widely. Some people may have multiple, severe infections while others show mild symptoms to none at all.\n\nMost commonly, people with activated PI3K-delta syndrome develop recurrent infections that begin in childhood, particularly in the lungs, sinuses, and ears. Over time, recurrent respiratory tract infections can lead to a condition called bronchiectasis, which damages the passages leading from the windpipe to the lungs (bronchi) and can cause breathing problems. People with activated PI3K-delta syndrome may also have chronic active viral infections, such as Epstein-Barr virus, herpes simplex virus, or cytomegalovirus infections.\n\nAnother possible feature of activated PI3K-delta syndrome is abnormal clumping of white blood cells. These clumps can lead to enlarged lymph nodes (lymphadenopathy) or an enlarged spleen (splenomegaly). The white blood cells can also build up to form solid masses (nodular lymphoid hyperplasia), usually in the moist lining of the airways or intestines. While nodular lymphoid hyperplasia is not cancerous (benign), activated PI3K-delta syndrome increases the risk of developing forms of blood cancer called Hodgkin lymphoma and non-Hodgkin lymphoma.\n\nSome people with activated PI3K-delta syndrome develop autoimmunity, which occurs when the body attacks its own tissues and organs by mistake.\n\nThere are two types of activated PI3K-delta syndrome, each with different genetic causes.

Lymphatic malformation-6 is a form of generalized lymphatic dysplasia (GLD), which is characterized by a uniform, widespread lymphedema affecting all segments of the body, with systemic involvement such as intestinal and/or pulmonary lymphangiectasia, pleural effusions, chylothoraces and/or pericardial effusions. In LMPHM6, there is a high incidence of nonimmune hydrops fetalis (NIHF) with either death or complete resolution of the neonatal edema, but childhood onset of lymphedema with or without systemic involvement also occurs. Mild facial edema is often present. Patients have normal intelligence and no seizures (summary by Fotiou et al., 2015). For a discussion of genetic heterogeneity of lymphatic malformation, see 153100.

Immunodeficiency-71 with inflammatory disease and congenital thrombocytopenia (IMD71) is an autosomal recessive immunologic disorder characterized by the onset of recurrent infections and inflammatory features such as vasculitis and eczema in infancy or early childhood. Infectious agents include bacteria and viruses. Laboratory findings are variable, but usually show thrombocytopenia, sometimes with abnormal platelet morphology, increased serum IgE, IgA, or IgM, leukocytosis, decreased or increased T lymphocytes, and increased eosinophils. Detailed studies show impaired neutrophil and T-cell chemotaxis, as well as impaired T-cell activation due to defects in F-actin (see 102610) polymerization (summary by Brigida et al., 2018).

Ehlers-Danlos syndrome classic-like-2 (EDSCLL2) is characterized by severe joint and skin laxity, osteoporosis involving the hips and spine, osteoarthritis, soft redundant skin that can be acrogeria-like, delayed wound healing with abnormal atrophic scarring, and shoulder, hip, knee, and ankle dislocations. Variable features include gastrointestinal and genitourinary manifestations, such as bowel rupture, gut dysmotility, cryptorchidism, and hernias; vascular complications, such as mitral valve prolapse and aortic root dilation; and skeletal anomalies (Blackburn et al., 2018). For a discussion of genetic heterogeneity of classic-like Ehlers-Danlos syndrome, see 606408. For a discussion of the classification of EDS, see 130000.

Hereditary primary lymphedema is caused by anatomic or functional defects in the lymphatic system, resulting in chronic swelling of body parts. There may be accompanying nail and skin changes, such as nail dysplasia or papillomatosis. Onset is usually at birth or in early childhood but can occur later, and the severity is variable (summary by Gordon et al., 2013 and Balboa-Beltran et al., 2014). For a discussion of genetic heterogeneity of lymphatic malformation, see 153100.

Any hereditary lymphedema in which the cause of the disease is a mutation in the VEGFC gene.

Hyper-IgE syndrome-5 with recurrent infections (HEIS5) is an autosomal recessive immunologic disorder characterized by onset of recurrent sinopulmonary and deep skin infections in early childhood. The infections are mostly caused by bacteria, including H. influenza and Staphylococcus aureus. Additional features include atopic dermatitis, impaired inflammatory responses during infection, increased serum IgE, and increased IL6 (147620) (summary by Spencer et al., 2019). For a discussion of genetic heterogeneity of hyper-IgE syndrome, see HIES1 (147060).

Immunodeficiency-73B with defective neutrophil chemotaxis (IMD73B) is an autosomal dominant immunologic disorder characterized by onset of recurrent infections in infancy or early childhood. Affected individuals develop respiratory infections, cellulitis, and severe invasive infections or sepsis; organisms include bacteria such as Staphylococcus, as well as viruses, fungi, and mycobacterial species. Laboratory studies show variable abnormalities, including B- and T-cell lymphopenia, decreased immunoglobulin subsets, decreased TRECs and dysfunctional T cells, decreased NK cells, neutropenia, and impaired neutrophil chemotaxis. Hematopoietic stem cell transplantation is curative (summary by Hsu et al., 2019; review by Lougaris et al., 2020). In a review of autosomal forms of chronic granulomatous disease (see 306400 for genetic heterogeneity of CGD), Roos et al. (2021) noted that patients with RAC2 mutations may manifest CGD-like symptoms due to defects in neutrophil NADPH oxidase activity.

Immunodeficiency-77 (IMD77) is an immunologic disorder characterized by recurrent and persistent polymicrobial infections with multiple unusual organisms. Skin and pulmonary infections are the most common, consistent with increased susceptibility to epithelial cell infections. The age at onset is highly variable: some patients have recurrent infections from childhood, whereas others present in late adulthood. The limited number of reported patients are all female, suggesting incomplete penetrance or a possible sex-influenced trait. Patient cells, mainly macrophages, show impaired killing of intracellular bacteria and organisms, including nontubercular mycobacteria, although there is also impaired killing of other organisms, such as Pseudomonas, Candida, and Aspergillus. Treatment with gamma-IFN (IFNG; 147570) may be a therapeutic option (summary by McCormack et al., 2017 and Merselis et al., 2020).