Trichorhinophalangeal syndrome (TRPS) comprises TRPS I (caused by a heterozygous pathogenic variant in TRPS1) and TRPS II (caused by contiguous gene deletion of TRPS1, RAD21, and EXT1). Both types of TRPS are characterized by distinctive facial features; ectodermal features (fine, sparse, depigmented, and slow growing hair; dystrophic nails; and small breasts); and skeletal findings (short stature; short feet; brachydactyly with ulnar or radial deviation of the fingers; and early, marked hip dysplasia). TRPS II is characterized by multiple osteochondromas (typically first observed clinically on the scapulae and around the elbows and knees between ages 1 month and 6 years) and an increased risk of mild-to-moderate intellectual disability.

Werner syndrome is characterized by the premature appearance of features associated with normal aging and cancer predisposition. Individuals with Werner syndrome develop normally until the end of the first decade. The first sign is the lack of a growth spurt during the early teen years. Early findings (usually observed in the 20s) include loss and graying of hair, hoarseness, and scleroderma-like skin changes, followed by bilateral ocular cataracts, type 2 diabetes mellitus, hypogonadism, skin ulcers, and osteoporosis in the 30s. Myocardial infarction and cancer are the most common causes of death; the mean age of death in individuals with Werner syndrome is 54 years.

Acrodermatitis enteropathica of the zinc deficiency type (AEZ) is characterized by intermittent simultaneous occurrence of diarrhea and dermatitis with failure to thrive. Alopecia of the scalp, eyebrows, and eyelashes is a usual feature. The skin lesions are bullous. Noteworthy is the cure by diodoquin, or diiodohydroxyquinoline (Dillaha et al., 1953; Bloom and Sobel, 1955). Rodin and Goldman (1969) described autopsy findings, including pancreatic islet hyperplasia, absence of the thymus and of germinal centers, and plasmocytosis of lymph nodes and spleen.

Perifolliculitis capitis abscedens et suffodiens is a chronic inflammatory disease of the scalp characterized by the presence of large and small nodules that suppurate and intercommunicate by sinus formation. It may be more frequent in black males than in others (summary by McMullan and Zeligman, 1956).

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.

A rare genetic disease characterized by childhood onset of bilateral progressive sensorineural hearing loss, ocular anomalies (myopia, cataract, retinitis pigmentosa), central and peripheral nervous system features (dementia, epilepsy, ataxia, peripheral neuropathy), ectodermal features (skin atrophy, alopecia, dental caries), and skeletal anomalies (bone cysts, joint stiffness, scoliosis, kyphosis). Laboratory examination may reveal elevated cerebrospinal fluid protein.

Wiedemann-Rautenstrauch syndrome (WDRTS) is a rare autosomal recessive neonatal progeroid disorder characterized by intrauterine growth retardation, failure to thrive, short stature, a progeroid appearance, hypotonia, and variable mental impairment (summary by Toriello, 1990). Average survival in WDRTS is 7 months, although survival into the third decade of life has been reported (Akawi et al., 2013).

Dermatopathia pigmentosa reticularis (DPR) is a rare heritable disorder consisting of a triad of cutaneous findings including reticulate hyperpigmentation, noncicatricial alopecia, and onychodystrophy. Variable features include adermatoglyphia, hypohidrosis or hyperhidrosis, and palmoplantar hyperkeratosis (Heimer et al., 1992).

Autosomal recessive congenital ichthyosis (ARCI) encompasses several forms of nonsyndromic ichthyosis. Although most neonates with ARCI are collodion babies, the clinical presentation and severity of ARCI may vary significantly, ranging from harlequin ichthyosis, the most severe and often fatal form, to lamellar ichthyosis (LI) and (nonbullous) congenital ichthyosiform erythroderma (CIE). These phenotypes are now recognized to fall on a continuum; however, the phenotypic descriptions are clinically useful for clarification of prognosis and management. Infants with harlequin ichthyosis are usually born prematurely and are encased in thick, hard, armor-like plates of cornified skin that severely restrict movement. Life-threatening complications in the immediate postnatal period include respiratory distress, feeding problems, and systemic infection. Collodion babies are born with a taut, shiny, translucent or opaque membrane that encases the entire body and lasts for days to weeks. LI and CIE are seemingly distinct phenotypes: classic, severe LI with dark brown, plate-like scale with no erythroderma and CIE with finer whiter scale and underlying generalized redness of the skin. Affected individuals with severe involvement can have ectropion, eclabium, scarring alopecia involving the scalp and eyebrows, and palmar and plantar keratoderma. Besides these major forms of nonsyndromic ichthyosis, a few rare subtypes have been recognized, such as bathing suit ichthyosis, self-improving collodion ichthyosis, or ichthyosis-prematurity syndrome.

Ectodermal dysplasia/skin fragility syndrome (EDSFS) is an autosomal recessive genodermatosis characterized by widespread skin fragility, alopecia, nail dystrophy, and focal keratoderma with painful fissures. Hypohidrosis and cheilitis are sometimes present (summary by Ersoy-Evans et al., 2006).

A rare genetic multiple congenital anomalies/dysmorphic syndrome with characteristics of severe short stature and craniofacial dysmorphism (microcephaly, narrow face with flat cheeks, ptosis, prominent nose with a convex ridge, low-set ears with small or absent lobes, high-arched/cleft palate, micrognathia), associated with premature greying and loss of scalp hair, redundant, dry and wrinkled skin of the palms, premature senility and varying degrees of intellectual disability. Cryptorchidism and skeletal anomalies may also be observed. There have been no further descriptions in the literature since 1970.

The TP63-related disorders comprise six overlapping phenotypes: Ankyloblepharon-ectodermal defects-cleft lip/palate (AEC) syndrome (which includes Rapp-Hodgkin syndrome). Acro-dermo-ungual-lacrimal-tooth (ADULT) syndrome. Ectrodactyly, ectodermal dysplasia, cleft lip/palate syndrome 3 (EEC3). Limb-mammary syndrome. Split-hand/foot malformation type 4 (SHFM4). Isolated cleft lip/cleft palate (orofacial cleft 8). Individuals typically have varying combinations of ectodermal dysplasia (hypohidrosis, nail dysplasia, sparse hair, tooth abnormalities), cleft lip/palate, split-hand/foot malformation/syndactyly, lacrimal duct obstruction, hypopigmentation, hypoplastic breasts and/or nipples, and hypospadias. Findings associated with a single phenotype include ankyloblepharon filiforme adnatum (tissue strands that completely or partially fuse the upper and lower eyelids), skin erosions especially on the scalp associated with areas of scarring, and alopecia, trismus, and excessive freckling.

The histiocytosis-lymphadenopathy plus syndrome comprises features of 4 histiocytic disorders previously thought to be distinct: Faisalabad histiocytosis (FHC), sinus histiocytosis with massive lymphadenopathy (SHML), H syndrome, and pigmented hypertrichosis with insulin-dependent diabetes mellitus syndrome (PHID). FHC was described as an autosomal recessive disease involving joint deformities, sensorineural hearing loss, and subsequent development of generalized lymphadenopathy and swellings in the eyelids that contain histiocytes (summary by Morgan et al., 2010). SHML, or familial Rosai-Dorfman disease, was described as a rare cause of lymph node enlargement in children, consisting of chronic massive enlargement of cervical lymph nodes frequently accompanied by fever, leukocytosis, elevated erythrocyte sedimentation rate, and polyclonal hypergammaglobulinemia. Extranodal sites were involved in approximately 25% of patients, including salivary glands, orbit, eyelid, spleen, and testes. The involvement of retropharyngeal lymphoid tissue sometimes caused snoring and sleep apnea (summary by Kismet et al., 2005). H syndrome was characterized by cutaneous hyperpigmentation and hypertrichosis, hepatosplenomegaly, heart anomalies, and hypogonadism; hearing loss was also found in about half of patients, and many had short stature. PHID was characterized by predominantly antibody-negative insulin-dependent diabetes mellitus associated with pigmented hypertrichosis and variable occurrence of other features of H syndrome, with hepatosplenomegaly occurring in about half of patients (Cliffe et al., 2009). Bolze et al. (2012) noted that mutations in the SLC29A3 gene (612373) had been implicated in H syndrome, PHID, FHC, and SHML, and that some patients presented a combination of features from 2 or more of these syndromes, leading to the suggestion that these phenotypes should be grouped together as 'SLC29A3 disorder.' Bolze et al. (2012) suggested that the histologic features of the lesions seemed to be the most uniform phenotype in these patients. In addition, the immunophenotype of infiltrating cells in H syndrome patients was shown to be the same as that seen in patients with the familial form of Rosai-Dorfman disease, further supporting the relationship between these disorders (Avitan-Hersh et al., 2011; Colmenero et al., 2012).

Severe combined immunodeficiency (SCID) due to DCLRE1C deficiency is a type of SCID (see this term) characterized by severe and recurrent infections, diarrhea, failure to thrive, and cell sensitivity to ionizing radiation.

Syndrome that has characteristics of dysmorphic features and intellectual deficit. It has been described in seven patients within one family. 17q11.2 microduplication encompasses the NF1 region. The underlying mechanism may be non-allelic homologous recombination. The study of pedigree suggests that this microduplication segregates within the family for at least two generations. Two patients displayed a normal clinical presentation, suggesting an autosomal dominant pattern of inheritance with incomplete penetrance.

Cardiofaciocutaneous (CFC) syndrome is characterized by cardiac abnormalities (pulmonic stenosis and other valve dysplasias, septal defects, hypertrophic cardiomyopathy, rhythm disturbances), distinctive craniofacial appearance, and cutaneous abnormalities (including xerosis, hyperkeratosis, ichthyosis, keratosis pilaris, ulerythema ophryogenes, eczema, pigmented moles, hemangiomas, and palmoplantar hyperkeratosis). The hair is typically sparse, curly, fine or thick, woolly or brittle; eyelashes and eyebrows may be absent or sparse. Nails may be dystrophic or fast growing. Some form of neurologic and/or cognitive delay (ranging from mild to severe) is seen in all affected individuals. Neoplasia, mostly acute lymphoblastic leukemia, has been reported in some individuals.

Epidermolysis bullosa simplex (EBS) is characterized by fragility of the skin (and mucosal epithelia in some instances) that results in non-scarring blisters and erosions caused by minor mechanical trauma. EBS is distinguished from other types of epidermolysis bullosa (EB) or non-EB skin fragility syndromes by the location of the blistering in relation to the dermal-epidermal junction. In EBS, blistering occurs within basal keratinocytes. The severity of blistering ranges from limited to hands and feet to widespread involvement. Additional features can include hyperkeratosis of the palms and soles (keratoderma), nail dystrophy, milia, and hyper- and/or hypopigmentation. Rare EBS subtypes have been associated with additional clinical features including pyloric atresia, muscular dystrophy, cardiomyopathy, and/or nephropathy.

Knobloch syndrome-1 (KNO1) is an autosomal recessive developmental disorder primarily characterized by typical eye abnormalities, including high myopia, cataracts, dislocated lens, vitreoretinal degeneration, and retinal detachment, with occipital skull defects, which can range from occipital encephalocele to occult cutis aplasia (summary by Aldahmesh et al., 2011). Genetic Heterogeneity of Knobloch Syndrome KNO2 (618458) is caused by mutation in the PAK2 gene (605022) on chromosome 3q29.

CAPOK syndrome (CAPOK) is characterized by onset of symptoms in the first year of life, with the development of progressive alopecia, hypo- and hyperpigmented macular skin lesions, palmoplantar keratoderma, and nail dystrophy. Beginning in the third decade of life, patients develop recurrent squamous cell carcinomas. Some patients may have brittle teeth resulting in tooth loss, and multinodular goiter has been observed (Courcet et al., 2015).

Intermediate junctional epidermolysis bullosa 5A (JEB5A) is an autosomal recessive blistering disease of skin and mucous membranes. Blistering is less severe than in severe JEB (see 226700). The plane of skin cleavage is through the lamina lucida of the cutaneous basement membrane zone. Nails may be dystrophic and dental enamel defects are present. Blistering does not affect the life span of affected individuals (summary by Has et al., 2020). For a discussion of genetic heterogeneity of the subtypes of JEB, see JEB1A (226650). Reviews Has et al. (2020) reviewed the clinical and genetic aspects, genotype-phenotype correlations, disease-modifying factors, and natural history of epidermolysis bullosa.