A multifocal, multisystem form of Langerhans-cell histiocytosis. There is involvement of multiple organ systems including the bones, skin, liver, spleen, and lymph nodes. Patients are usually infants presenting with fever, hepatosplenomegaly, lymphadenopathy, bone and skin lesions, and pancytopenia.

Gorham-Stout disease (GSD) is a rare disease of massive osteolysis associated with proliferation and dilation of lymphatic vessels. GSD may affect any bone in the body and can be monostotic or polyostotic. Symptoms at presentation are dependent upon the location(s) of the disease; the most common symptom is localized pain. The disease may be discovered after a pathological fracture.

Fibromatosis arising from the soft tissues of the penis. It is characterized by the presence of spindle-shaped fibroblasts, and an infiltrative growth pattern. It causes the penis to bend when it becomes erect.

An episodic vasoconstriction resulting in discoloration of the skin and pain in the affected areas, often involving fingers or toes. Classically associated with triphasic color changes (white, blue, red) but may be biphasic. Often occurs in response to cold temperatures or emotional stress. May be primary or secondary to an underlying autoimmune disease.

Rotor syndrome is characterized by mild conjugated and unconjugated hyperbilirubinemia that usually begins shortly after birth or in childhood. Jaundice may be intermittent. Conjunctival icterus may be the only clinical manifestation.

Skoog (1948) defined knuckle pads as 'subcutaneous nodules on the dorsal aspect of the proximal interphalangeal joints.'

Tibial hemimelia is a rare anomaly characterized by deficiency of the tibia with relatively intact fibula. Jones et al. (1978) classified the anomaly into 4 types according to radiologic criteria. It may present as an isolated anomaly or be associated with a variety of skeletal and extraskeletal malformations. Tibial hemimelia may also constitute a part of a more complicated malformation complex or syndrome, such as the Gollop-Wolfgang complex (228250) and triphalangeal thumb-polysyndactyly syndrome (see 174500 and 188740) (Matsuyama et al., 2003). McKay et al. (1984) reviewed syndromes of congenital defects in which tibial hemimelia is a feature.

In the resting position, the tip of the thumb is on, or near, the palm, close to the base of the fourth or fifth finger.

A rare bone development disorder characterized by localized, asymmetric osteochondral overgrowth affecting single or multiple epiphyses, most commonly the distal femur, proximal tibia, and talus. The lesions are typically restricted to one side of the epiphysis, with the medial side being affected twice as often as the lateral side. The condition is usually diagnosed in children, and three times more often in boys than in girls. Patients present with pain, limitation in range of motion, and deformity or swelling of the affected joint.

Spinocerebellar ataxia type 2 (SCA2) is characterized by progressive cerebellar ataxia, including nystagmus, slow saccadic eye movements, and in some individuals, ophthalmoparesis or parkinsonism. Pyramidal findings are present; deep tendon reflexes are brisk early on and absent later in the course. Age of onset is typically in the fourth decade with a ten- to 15-year disease duration.

Syndrome that is characterised by intellectual deficit, choroideraemia, acrokeratosis verruciformis, anhidrosis, and skeletal deformities. It has been observed in a single kindred. The syndrome is transmitted as an X-linked recessive trait and may be caused by a small X-chromosome deletion.

A chronic adhesive arachnoiditis in the spinal arachnoid, with root and spinal cord symptoms similar to those caused by pressure from a tumor.

This syndrome is characterized by osteopetrosis, agenesis of the corpus callosum, cerebral atrophy and a small hippocampus.

This autosomal recessive neurodevelopmental disorder is characterized by pachygyria, mental retardation, seizures, and diffuse localization of arachnoid cysts. It most likely represents a neuronal migration disorder within the lissencephaly spectrum (summary by Guzel et al., 2007).

A rare neuro-ophthalmological disorder characterised by a congenital sensory deficit involving all or some of the sensory components of the trigeminal nerve. Due to corneal anaesthesia, it usually presents with recurrent, painless eye infections, painless corneal opacities and/or poorly healing, ulcerated wounds on the facial skin and mucosa (typically the buccal mucosa and/or nasal septum).

Ectodermal dysplasia-intellectual disability-central nervous system malformation syndrome is a rare, multiple developmental anomalies syndrome characterized by the triad of ectodermal dysplasia (mostly hypohidrotic with dry skin and reduced sweating and sparse, fair scalp hair, eyebrows and eyelashes), severe intellectual disability and variable central nervous system anomalies (cerebellar hypoplasia, dilatation of ventricles, corpus callosum agenesis, Dandy-Walker malformation). Distinct craniofacial dysmorphism with macrocephaly, frontal bossing, midfacial hypoplasia and high arched or cleft palate, as well as cryptorchidism, feeding difficulties and hypotonia, are associated. There have been no further descriptions in the literature since 1998.

PNPLA6 disorders span a phenotypic continuum characterized by variable combinations of cerebellar ataxia; upper motor neuron involvement manifesting as spasticity and/or brisk reflexes; chorioretinal dystrophy associated with variable degrees of reduced visual function; and hypogonadotropic hypogonadism (delayed puberty and lack of secondary sex characteristics). The hypogonadotropic hypogonadism occurs either in isolation or as part of anterior hypopituitarism (growth hormone, thyroid hormone, or gonadotropin deficiencies). Common but less frequent features are peripheral neuropathy (usually of axonal type manifesting as reduced distal reflexes, diminished vibratory sensation, and/or distal muscle wasting); hair anomalies (long eyelashes, bushy eyebrows, or scalp alopecia); short stature; and impaired cognitive functioning (learning disabilities in children; deficits in attention, visuospatial abilities, and recall in adults). Some of these features can occur in distinct clusters on the phenotypic continuum: Boucher-Neuhäuser syndrome (cerebellar ataxia, chorioretinal dystrophy, and hypogonadotropic hypogonadism); Gordon Holmes syndrome (cerebellar ataxia, hypogonadotropic hypogonadism, and – to a variable degree – brisk reflexes); Oliver-McFarlane syndrome (trichomegaly, chorioretinal dystrophy, short stature, intellectual disability, and hypopituitarism); Laurence-Moon syndrome; and spastic paraplegia type 39 (SPG39) (upper motor neuron involvement, peripheral neuropathy, and sometimes reduced cognitive functioning and/or cerebellar ataxia).

A lethal malformation syndrome reported in 2 brothers of first-cousin parents with characteristics of hydrocephalus, cardiac malformation, dense bones and unusual facies with down-slanting palpebral fissures, bulbous nose, broad nasal bridge, micrognathia and a long upper lip. Transmission is likely autosomal recessive. There have been no further descriptions in the literature since 1984.

CDG IIe is caused by a mutation that impairs the integrity of the conserved oligomeric Golgi (COG) complex and alters Golgi trafficking, resulting in the disruption of multiple glycosylation pathways. For a general discussion of CDGs, see CDG1A (212065).

Patients with SSOAD exhibit a broad phenotypic spectrum involving short stature associated with advanced bone maturation and early-onset osteoarthritis (OA), as well as mild dysmorphic features consisting of midface hypoplasia, brachydactyly, broad great toes, and lumbar lordosis. Other features include intervertebral disc disease and osteochondritis dissecans, which is characterized by separation of articular cartilage and subchondral bone from the articular surface. Phenotypes are highly variable even among patients within the same family, and there are no apparent genotype-phenotype correlations (Dateki et al., 2017). The term 'dissecans' comes from 'dis' meaning 'from' and 'secare' meaning 'cut off,' and is not to be confused with 'desiccans' derived from 'desiccare' meaning to 'dry up.' Dissecans refers to the appearance of part of the bone having been cut away.

A rare idiopathic, benign respiratory disease characterized by submucosal cartilaginous and/or bony nodules presenting in the trachea with or without the involvement of the major bronchi; involvement is potentially anywhere along the anterior and lateral walls of the tracheobronchial tree with sparing the posterior walls.

Galloway-Mowat syndrome-7 (GAMOS7) is an autosomal recessive disorder characterized by developmental delay, microcephaly, and early-onset nephrotic syndrome (summary by Rosti et al., 2017). For a general phenotypic description and a discussion of genetic heterogeneity of GAMOS, see GAMOS1 (251300).

Developmental delay, impaired speech, and behavioral abnormalities (DDISBA) is characterized by global developmental delay apparent from early childhood. Intellectual disability can range from mild to severe. Additional variable features may include dysmorphic facial features, seizures, hypotonia, motor abnormalities such as Tourette syndrome or dystonia, and hearing loss (summary by Cousin et al., 2021).