Chediak-Higashi syndrome (CHS) is characterized by partial oculocutaneous albinism, immunodeficiency, and a mild bleeding tendency. Approximately 85% of affected individuals develop the accelerated phase, or hemophagocytic lymphohistiocytosis, a life-threatening, hyperinflammatory condition. All affected individuals including adolescents and adults with atypical CHS and children with classic CHS who have successfully undergone allogenic hematopoietic stem cell transplantation (HSCT) develop neurologic findings during early adulthood.

Vascular Ehlers-Danlos syndrome (vEDS) is characterized by arterial, intestinal, and/or uterine fragility; thin, translucent skin; easy bruising; characteristic facial appearance (thin vermilion of the lips, micrognathia, narrow nose, prominent eyes); and an aged appearance to the extremities, particularly the hands. Vascular dissection or rupture, gastrointestinal perforation, or organ rupture are the presenting signs in most adults with vEDS. Arterial rupture may be preceded by aneurysm, arteriovenous fistulae, or dissection but also may occur spontaneously. The majority (60%) of individuals with vEDS who are diagnosed before age 18 years are identified because of a positive family history. Neonates may present with clubfoot, hip dislocation, limb deficiency, and/or amniotic bands. Approximately half of children tested for vEDS in the absence of a positive family history present with a major complication at an average age of 11 years. Four minor diagnostic features – distal joint hypermobility, easy bruising, thin skin, and clubfeet – are most often present in those children ascertained without a major complication.

Leukocyte adhesion deficiency (LAD) is an autosomal recessive disorder of neutrophil function resulting from a deficiency of the beta-2 integrin subunit of the leukocyte cell adhesion molecule. The leukocyte cell adhesion molecule is present on the surface of peripheral blood mononuclear leukocytes and granulocytes and mediates cell-cell and cell-extracellular matrix adhesion. LAD is characterized by recurrent bacterial infections; impaired pus formation and wound healing; abnormalities of a wide variety of adhesion-dependent functions of granulocytes, monocytes, and lymphocytes; and a lack of beta-2/alpha-L, beta-2/alpha-M, and beta-2/alpha-X expression. Genetic Heterogeneity of Leukocyte Adhesion Deficiency Also see LAD2 (266265), caused by mutation in the SLC35C1 gene (605881), and LAD3 (612840), caused by mutation in the FERMT3 gene (607901).

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.

Kindler syndrome (KS), a rare subtype of inherited epidermolysis bullosa, is characterized by skin fragility and acral blister formation beginning at birth, diffuse cutaneous atrophy, photosensitivity (most prominent during childhood and usually decreasing after adolescence), poikiloderma, diffuse palmoplantar hyperkeratosis, and pseudosyndactyly. Mucosal manifestations are also common and include hemorrhagic mucositis and gingivitis, periodontal disease, premature loss of teeth, and labial leukokeratosis. Other mucosal findings can include ectropion, urethral stenosis, and severe phimosis. Severe long-term complications of KS include periodontitis, mucosal strictures, and aggressive squamous cell carcinomas. Manifestations can range from mild to severe.

Geroderma osteodysplasticum (GO) is an autosomal recessive disorder characterized by skin wrinkling limited to the dorsa of hands and feet and to the abdomen, bowed long bones, and osteopenia with frequent fractures. There is a distinctive facial appearance with droopy skin at the cheeks, maxillary hypoplasia, and large ears. Adult patients appear prematurely aged (summary by Rajab et al., 2008).

Hermansky-Pudlak syndrome (HPS) is characterized by oculocutaneous albinism, a bleeding diathesis, and, in some individuals, pulmonary fibrosis, granulomatous colitis, or immunodeficiency. Ocular findings include reduced iris pigment with iris transillumination, reduced retinal pigment, foveal hypoplasia with significant reduction in visual acuity (usually in the range of 20/50 to 20/400), nystagmus, and increased crossing of the optic nerve fibers. Hair color ranges from white to brown; skin color ranges from white to olive and is usually a shade lighter than that of other family members. The bleeding diathesis can result in variable bruising, epistaxis, gingival bleeding, postpartum hemorrhage, colonic bleeding, and prolonged bleeding with menses or after tooth extraction, circumcision, and other surgeries. Pulmonary fibrosis, a restrictive lung disease, typically causes symptoms in the early thirties and can progress to death within a decade. Granulomatous colitis is severe in about 15% of affected individuals. Neutropenia and/or immune defects occur primarily in individuals with pathogenic variants in AP3B1 and AP3D1.

Congenital plasminogen deficiency is a rare autosomal recessive disorder characterized clinically by chronic mucosal pseudomembranous lesions consisting of subepithelial fibrin deposition and inflammation. The most common clinical manifestation is ligneous ('wood-like') conjunctivitis, a redness and subsequent formation of pseudomembranes mostly on the palpebral surfaces of the eye that progress to white, yellow-white, or red thick masses with a wood-like consistency that replace the normal mucosa. The lesions may be triggered by local injury and/or infection and often recur after local excision. Pseudomembranous lesions of other mucous membranes often occur in the mouth, nasopharynx, trachea, and female genital tract. Some affected children also have congenital occlusive hydrocephalus. A slightly increased female:male ratio has been observed (1.4:1 to 2:1) (Schuster and Seregard, 2003; Tefs et al., 2006). Type I plasminogen deficiency is characterized by decreased serum plasminogen activity, decreased plasminogen antigen levels, and clinical symptoms, whereas type II plasminogen deficiency, also known as 'dysplasminogenemia,' is characterized by decreased plasminogen activity with normal or slightly reduced antigen levels. Patients with type II deficiency are usually asymptomatic. Ligneous conjunctivitis and pseudomembranous formation has only been associated with type I plasminogen deficiency. Presumably, normal amounts of plasminogen antigen with decreased activity, as seen in type II, is sufficient for normal wound healing (Schuster and Seregard, 2003).

Periodontal Ehlers-Danlos syndrome (pEDS) is characterized by distinct oral manifestations. Periodontal tissue breakdown beginning in the teens results in premature loss of teeth. Lack of attached gingiva and thin and fragile gums lead to gingival recession. Connective tissue abnormalities of pEDS typically include easy bruising, pretibial plaques, distal joint hypermobility, hoarse voice, and less commonly manifestations such as organ or vessel rupture. Since the first descriptions of pEDS in the 1970s, 148 individuals have been reported in the literature; however, future in-depth descriptions of non-oral manifestations in newly diagnosed individuals with a molecularly confirmed diagnosis of pEDS will be important to further define the clinical features.

Periodontal Ehlers-Danlos syndrome (pEDS) is characterized by distinct oral manifestations. Periodontal tissue breakdown beginning in the teens results in premature loss of teeth. Lack of attached gingiva and thin and fragile gums lead to gingival recession. Connective tissue abnormalities of pEDS typically include easy bruising, pretibial plaques, distal joint hypermobility, hoarse voice, and less commonly manifestations such as organ or vessel rupture. Since the first descriptions of pEDS in the 1970s, 148 individuals have been reported in the literature; however, future in-depth descriptions of non-oral manifestations in newly diagnosed individuals with a molecularly confirmed diagnosis of pEDS will be important to further define the clinical features.

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.

Odontochondrodysplasia-2 with hearing loss and diabetes (ODCD2) is characterized by growth retardation with proportionate short stature, dentinogenesis imperfecta, sensorineural hearing loss, insulin-dependent diabetes, and mild intellectual disability (Cauwels et al., 2005; Lekszas et al., 2020). For a discussion of genetic heterogeneity of ODCD, see ODCD1 (184260).