TaoMedAI/RareMedData huggingface dataset:
Leukoencephalopathy-thalamus and brainstem anomalies-high lactate syndrome (ORPHA:314051)
A rare, genetic neurological disorder defined by early-onset of neurologic symptoms, biphasic clinical course, unique MRI features (incl. extensive, symmetrical, deep white matter abnormalities), and increased lactate in body fluids. The severe form is characterized by delayed psychomotor development, seizures, early-onset hypotonia, and persistently increased lactate levels. The mild form usually presents with irritability, psychomotor regression after six months of age, and temporary high lactate levels, with overall clinical improvement from the second year onward.
Leukomelanoderma-infantilism-intellectual disability-hypodontia-hypotrichosis syndrome (ORPHA:1816)
Leukomelanoderma-infantilism-intellectual disability-hypodontia-hypotrichosis syndrome is a rare ectodermal dysplasia syndrome characterized by congenital generalized melanoleukoderma, hypodontia and hypotrichosis associated with infantilism, intellectual disability and growth delay. There have been no further descriptions in the literature since 1961.
Leukonychia totalis-acanthosis-nigricans-like lesions-abnormal hair syndrome (ORPHA:210133)
Leukonychia totalis-acanthosis-nigricans-like lesions-abnormal hair syndrome is a rare, syndromic nail anomaly disorder characterized by the association of leukonychia totalis with acanthosis-nigricans-like lesions (occurring in the neck, axillae and abdomen regions) and hair dysplasia, manifesting with dry, brittle hair which presents an irregular pattern of complete or incomplete twists and an irregular surface with londitudinal furrows on electronic microscopy.
Leukonychia totalis (ORPHA:2387)
Leukonychia totalis is a rare nail anomaly disorder characterized by complete white discoloration of the nails. Patients typically present white, chalky nails as an isolated finding, although other cutaneous or systemic manifestations could also be present.
Levocardia (ORPHA:95854)
A rare, congenital, non-syndromic, developmental defect during embryogenesis characterized by the heart located in the normal (levo) position associated with abdominal viscera located in the dextro position. Cardiac (e.g. interrupted inferior vena cava with azygous continuation) and/or splenic (asplenia, polysplenia) anomalies, as well as intestinal malrotation, are frequently associated.
Lewis-Sumner syndrome (ORPHA:48162)
A rare acquired demyelinating polyneuropathy characterized by asymmetrical distal weakness of the upper or lower extremities and motor dysfunction with adult onset. It is considered to be a variant of chronic inflammatory demyelinating polyneuropathy.
Leydig cell hypoplasia (ORPHA:755)
A rare 46,XY difference of sex development due to impaired androgen production characterized by impaired normal male sexual development. The severity of the disorder varies and can manifest in its severe form with complete 46,XY male pseudohermaphroditism, including low testosterone and high luteinizing hormone levels, absent development of secondary male sex characteristics and lack of breast development. Patients with the milder form can have a wider range of phenotypes, ranging from micropenis to severe hypospadias.
Lhermitte-Duclos disease (ORPHA:65285)
A rare developmental defect during embryogenesis characterized by abnormal development and enlargement of the cerebellum, and an increased intracranial pressure. The tumors can be characterized by the abnormal growth of ganglion cells that regulate activities in the cerebellum.
Epidemiology
Approximately 230 cases of Lhermitte-Duclos disease (LDD) have been reported in literature to date, there is no sex or race preference. It typically presents between ages of 30-50, although it may occur in infants and adults over age of 60.
Clinical description
It manifests, most commonly in the third and fourth decades of life, with headache, nausea, cerebellar dysfunction, occlusive hydrocephalus, ataxia, visual disturbances and other cranial nerve palsies. Various associated abnormalities may be present (megalencephaly, microgyria, hydromyelia, polydactyly, partial gigantism, macroglossia). Co-existing conditions include Cowden syndrome.
Etiology
The etiology is uncertain; germline mutations in tumor suppressor gene PTEN have been identified in some patients with LDD.
Diagnostic methods
Diagnosis of LDD is confirmed by magnetic resonance imaging (MRI) and genetic testing for germline PTEN pathogenic variant.
Differential diagnosis
Differential diagnosis include Cowden syndrome as LDD can co-manifest along with Cowden syndrome features.
Antenatal diagnosis
Antenatal diagnosis is possible if the pathogenic variant has previously been identified in the family, but was never described in the literature.
Genetic counseling
This is an autosomal dominant condition which may occur sporadically or in a familial form. Genetic counseling should be offered to at-risk family members to inform them of the 50% risk of transmission for each pregnancy.
Management and treatment
Management includes decompressive surgical intervention.
Prognosis
There is no data regarding the prognosis of this disease.

                            Last update: 
                            December 2023


                            - Expert reviewer(s): 
                             Manasadevi KARTHIKEYAN  - Dr Joanne NGEOW
Lichen amyloidosis (ORPHA:49804)
Lichen amyloidosis is a rare chronic form of cutaneous amyloidosis (see this term), a skin disease characterized by the accumulation of amyloid deposits in the dermis, clinically characterized by the development of pruritic, often pigmented, hyperkeratotic papules on trunk and extremities, especially on the shins, and histologically by the deposition of amyloid or amyloid-like proteins in the papillary dermis.
Lichen planopilaris (ORPHA:525)
A rare cutaneous variant of lichen planus which affects hair follicles. It may occur on its own or in association with more common forms of lichen planus, usually classical type and/or oral lichen planus.
Epidemiology
The prevalence is unknown. LPP is more frequent in women than in men.
Clinical description
The disease manifests in adulthood (40-60 years of age), with some rare cases in childhood. Patients present with peri-follicular inflammation and hair loss. They may be asymptomatic or have itch or discomfort. The scalp is the commonest area affected but any hair bearing skin may be affected, like for example the axillae or the pubic area. Perifollicular erythema, scales, and/or keratotic plugs are seen at the edge of the affected area. Single or multiple lesions of scarring alopecia lacking follicular orifices are typical. Two other variants of LPP can be observed: frontal fibrosing alopecia (FFA), and Lassueur-Graham-Little syndrome (see these terms). In FFA, there is symmetrical, progressive anterior hairline loss of the scalp associated with eyebrow loss. The Lassueur-Graham-Little syndrome constitutes a combination of lichen planus follicularis of the scalp with follicular keratosis and noncicatricial alopecia of the axillae and pubes.
Etiology
Etiology is unknown but LPP is thought to be an autoimmune disorder in which T-lymphocytes attack and destroy keratinocytes expressing unknown target antigens. Triggering factors could be pharmacologic agents, contact sensitizers or infectious agents.
Diagnostic methods
Diagnosis is based on clinical and histopathological findings. Biopsy of an inflammatory lesion shows a band-like perifollicular lymphocytic infiltrate at the level of the isthmus and infundibulum. There may be vacuolar changes of the basal layer and follicular plugging. In more advanced lesions, perifollicular fibrosis and replacement of hair follicles by fibrosis are found. Diagnosis is difficult in the later stages when inflammation disappears.
Differential diagnosis
Differential diagnosis includes discoid lupus erythematosus (DLE), folliculitis decalvans, mucous membrane pemphigoid (see these terms), seborrheic dermatitis, alopecia areata, and central centrifugal cicatricial alopecia (CCCA).
Management and treatment
There is no long-term effective treatment for LPP. Current treatments aim at slowing down progression of hair loss and reduction of symptoms. Topical, intralesional and oral corticosteroids are the mainstay of treatment. Unfortunately, relapse is common. Other options for treatment include hydroxychloroquinine, ciclosporin and methotrexate.
Prognosis
LPP can progress slowly or rapidly. Some cases may spontaneously resolve but others are progressive.

                            Last update: 
                            March 2011


                            - Expert reviewer(s): 
                            Dr Susan COOPER
Lichen planus pemphigoides (ORPHA:254478)
Lichen planus (LP) pemphigoides is a rare cross-over syndrome between lichen planus and bullous pemphigoid (see these terms).
Epidemiology
The prevalence is unknown.
Clinical description
LP pemphigoides affects primarily adult men in middle age (40-50 years of age), but several cases have been reported in children. It is quite distinct from bullous lichen planus (see this term), both clinically and pathologically. In lichen planus pemphigoides, bullous lesions arise in both normal skin and skin affected by lichenoid lesions, whereas in bullous lichen planus, the blisters only develop on lichenoid papules. The bullae in LP pemphigoides can be hemorrhagic or clear, and have a predilection for acral sites.
Etiology
Epitope spreading seems to account for the pathogenesis of lichen planus pemphigoides, whereby damage to the basal layer in LP lesions exposes a basement membrane antigen (e.g. BP180 epitope) leading to the development of circulating antibodies. Occurrence of LP pemphigoides has been reported following the use of several medications including cinnarizine, angiotensin-converting enzyme (ACE) inhibitors (ramipril and captopril), simvastatin and anti-tuberculous drugs, and also following Psoralen and Ultraviolet A Light (PUVA) therapy.

                            Last update: 
                            May 2011


                            - Expert reviewer(s): 
                            Dr Stephanie ARNOLD  - Dr Susan COOPER
Lichen planus pigmentosus (ORPHA:254463)
Lichen planus (LP) pigmentosus is a rare variant of cutaneous lichen planus (see this term) characterized by the presence of hyperpigmented lichenoid lesions in sun-exposed or flexural areas of the body.
Epidemiology
LP pigmentosus is a rare disease in Europe but it is common in Indian populations and in the Middle East. The overall prevalence is unknown. There is no difference in distribution between males and females.
Clinical description
The disease usually appears in the third and fourth decade of life. The lesions are asymptomatic or mildly pruritic. Skin changes are dark brown or slate grey macules or papules with, in most cases, a diffuse pigmentation pattern. They most commonly affect the face, neck and upper limbs. Predominantly a intertriginous disease, usually in the axillae and groin (described mostly in Caucasians), it has also been termed as lichen planus pigmentosus inversus. The scalp, nails or mucosa are not affected. LP pigmentosus can exist in association with typical LP lesions.
Etiology
Etiology is unknown but various factors (e.g. viral infections and certain topical agents including mustard oil, amla oil and henna hair dyes) can trigger the disease. One case has been reported in association with Bazex syndrome (see this term).
Diagnostic methods
Histological features of LP pigmentosus are similar but milder than classic LP, with a lichenoid interface reaction, vacuolar change and apoptotic keratinocytes. Melanin incontinence is prominent, and may be the only feature of older lesions; it may extend deeper into the dermis than typical post-inflammatory pigmentation.
Prognosis
Lichen planus pigmentosa seems to follow a chronic progressive course.

                            Last update: 
                            May 2011


                            - Expert reviewer(s): 
                            Dr Stephanie ARNOLD  - Dr Susan COOPER
Lichtenstein syndrome (ORPHA:2390)
A rare genetic disease characterized by frequent infections associated with neutropenia and IgA deficiency, in combination with osteoporosis and skeletal anomalies, such as posterior spinal arch fusion defect, metacarpal subluxation, syndactyly, and camptodactyly. Reported dysmorphic features include synophrys, anteverted nostrils, and single palmar crease. There have been no further descriptions in the literature since 1972.
LIG4 syndrome (ORPHA:99812)
LIG4 syndrome is a hereditary disorder associated with impaired DNA double-strand break repair mechanisms and characterized by microcephaly, unusual facial features, growth and developmental delay, skin anomalies, and pancytopenia, which is associated with combined immunodeficiency (CID).
Epidemiology
Prevalence is unknown. To date, at least 12 patients have been reported.
Clinical description
LIG4 syndrome presents in childhood with microcephaly, unusual facial features that have been described as ''bird-like'' (beak-like nose and micrognathia), growth and developmental delay, skin anomalies including photosensitivity and psoriatic-like lesions, and pancytopenia. The disease is associated with immunodeficiency. Some patients have been reported as having telangiectasias, leukemia, lymphoma, bone marrow abnormalities, and type 2 diabetes. One patient presented with features of Omenn syndrome (see this term).
Etiology
LIG4 syndrome is caused by mutations in the LIG4 gene (13q22-q34). The resulting defect of DNA ligase IV, a component of the classical non-homologous end-joining (NHEJ) pathway, affects the major mechanism of DNA double-strand break repair.
Diagnostic methods
Diagnosis is based on evidence of the characteristic clinical signs of LIG4 syndrome, particularly the ''bird-like'' facial features, and low T and B cells. Diagnosis is confirmed on the basis of molecular genetic analysis and the evidence of radiosensitivity of cell lines. Chromosome 7/14 translocations are also common.
Differential diagnosis
Differential diagnoses include other rare DNA damage response diseases such as Seckel syndrome, Nijmegen breakage syndrome (NBS), Cernunnos-XLF deficiency and Fanconi anemia (see these terms).
Antenatal diagnosis
Prenatal diagnosis can be performed by chorionic villus sampling in families with previously affected members.
Genetic counseling
Transmission is autosomal recessive.
Management and treatment
Supportive treatment is with prophylactic antibiotics and anti-virals. Hematopoietic stem cell transplantation may be indicated in some patients using modified conditioning regimens without radiotherapy.
Prognosis
Lifespan is generally limited with an increased incidence of leukemia or lymphoma.

                            Last update: 
                            July 2012


                            - Expert reviewer(s): 
                            Pr Andrew GENNERY
Light and heavy chain deposition disease (ORPHA:93557)
A rare non-amyloid monoclonal immunoglobulin deposition disease characterized by secretion of abnormal light and heavy chains, which are deposited in tissues and cause organ dysfunction, but do not form amyloid beta-pleated sheets or contain an amyloid P component. The condition most frequently occurs in association with multiple myeloma. The kidneys are most commonly affected (clinically manifesting as nephrotic syndrome and renal failure), but liver, heart, peripheral nerves, blood vessels, and joints may also be involved.
Light chain deposition disease (ORPHA:93558)
A rare non-amyloid monoclonal immunoglobulin deposition disease characterized by deposition of abnormal immunoglobulin light chains in the kidneys, resulting in nephrotic syndrome and renal failure. Symptomatic extrarenal deposition is uncommon, although hepatic, cardiac, and neural deposits have been reported. The condition frequently occurs in association with multiple myeloma or in patients with M protein and marrow plasma cells at monoclonal gammopathy of undetermined significance levels.
Limb body wall complex (ORPHA:2369)
Limb body wall complex (LBWC) is characterized by severe multiple congenital anomalies in the fetus with exencephaly/encephalocele, thoraco- and/or abdominoschisis (anterior body wall defects) and limb defects, with or without facial clefts.
Epidemiology
Approximately 250 cases have been reported in the literature so far.
Clinical description
Clinical manifestations vary widely and include limb defects and visceral malformations (95% of cases), spinal abnormalities, absent diaphragm, bowel atresia and renal agenesis. LBWC generally presents as a short umbilical cord, abdominal placental attachment, persistence of an extraembryonic celom, anorectal malformations, urogenital abnormalities, lumbosacral meningomyelocele and kyphoscoliosis. A spectrum of LBWC manifestations is included in the amniotic band sequence (see this term), presenting mostly with craniofacial defects, facial clefts, amniotic bands and/or adhesions. At present, it remains unclear whether these two entities represent a single disorder.
Etiology
The etiology of LBWC remains unknown. Karyotypes have been reported as normal and no correlations with gender, parental age and teratogenic agents have been found. The principal theories are an extrinsic origin by early amniotic rupture, or a vascular origin due to an early vascular accident during embryological development. Single cases of familial occurrence have been documented.
Diagnostic methods
Diagnosis is based on the presenting features.
Differential diagnosis
LBWC should be differentiated from gastroschisis (see this term), which has better prognosis.
Antenatal diagnosis
Early antenatal diagnosis is feasible by ultrasound examination and may be followed by medical termination of the pregnancy.
Prognosis
LBWC is fatal, with death occurring antenatally or early in the neonatal period.

                            Last update: 
                            March 2009


                            - Expert reviewer(s): 
                            Pr Didier LACOMBE
Limb-girdle muscular dystrophy due to POMK deficiency (ORPHA:445110)
Limb-girdle muscular dystrophy due to POMK deficiency is a form of limb-girdle muscular dystrophy presenting in infancy with muscle weakness and delayed motor development (eventually learning to walk at 18 months of age) followed by progressive proximal weakness, pseudohypertrophy of calf muscles, mild facial weakness, and borderline intelligence.
Limb-mammary syndrome (ORPHA:69085)
A rare, genetic, ectodermal dysplasia syndrome characterized by severe hand/foot anomalies, breast and/or nipple hypoplasia, and ectodermal dysplasia (principally teeth and nail anomalies). Cleft lip/palate may be variably present.
Limbal stem cell deficiency (ORPHA:171673)
A rare corneal disorder characterized by dysfunction and/or insufficient quantity of corneal limbal stem cells, leading to impaired self-renewal of the corneal epithelium and resulting in epithelial breakdown, corneal conjunctivalization and neovascularization, chronic inflammation, persistent epithelial defects, and scarring. Patients usually present with ocular redness, decreased vision, photophobia, foreign body sensation, tearing, and pain. The condition may be genetic, idiopathic, or acquired (in the context of inflammation, infection, trauma, or ocular surface tumors).
Limited systemic sclerosis (ORPHA:220407)
Limited systemic sclerosis (lSSc) (or SSc sine scleroderma) is a subset of systemic sclerosis (SSc; see this term) characterized by organ involvement in the absence of fibrosis of the skin.
Epidemiology
Prevalence is unknown.
Clinical description
Patients do not have skin fibrosis but only Raynaud's phenomenon, and are at risk of organ involvement (fibrosis and vascular obliteration of lungs, heart, digestive tract). They can later present with esophageal dysmotility which provokes gastroesophageal reflux and sometimes dysphagia, and can also suffer from lung fibrosis and pulmonary arterial hypertension.
Etiology
The exact cause of lSSc is unknown. The disease originates from an autoimmune reaction which leads to overproduction of collagen. In some cases, SSc is associated with exposure to chemicals (silica, solvents, hydrocarbons, etc.).
Diagnostic methods
Diagnosis can be difficult due to the absence of skin involvement. Nailfold capillaroscopy shows a SSc pattern and blood tests show a high incidence of anti-centromere antibodies.

                            Last update: 
                            July 2010


                            - Expert reviewer(s): 
                            Pr Eric HACHULLA
Linear and whorled nevoid hypermelanosis (ORPHA:79150)
A rare hyperpigmentation of the skin disease characterized by the congenital to infantile-onset of bilateral, diffuse (occasionally localized), reticulate (swirls and streaks), macular hyperpigmentation following the lines of Blaschko, typically involving the trunk, limbs, head and neck (but sparing palms, soles and mucosa), without preceding inflammation, blistering or atrophy. Occasionally, extracutaneous abnormalities, including autism, seizures, cardiac defects, skeletal abnormalities and developmental delay, may be associated. Histologically, basal and/or suprabasal melanosis, without pigment incontinence, is observed.
Linear atrophoderma of Moulin (ORPHA:140933)
Linear atrophoderma of Moulin (LAM) is characterized by mildly atrophic and hyperpigmented band-like lesions that follow the lines of Blaschko on the trunk or limbs. Since its initial description in 1992, less than 30 cases have been reported in the literature. Onset occurs during childhood or adolescence and the disease is non-progressive. There is no prior inflammation or subsequent scleroderma. The aetiology is unknown but as LAM follows the lines of Blaschko it has been suggested that the disease is caused by mosaicism of a predisposing gene.
Linear focal elastosis (ORPHA:228236)
Linear focal elastosis is a rare, acquired, dermis elastic tissue disorder characterized by asymptomatic, palpable, hypertrophic or atrophic, yellowish or red, indurated, horizontal, striae-like linear plaques distributed symmetrically across the mid and lower back. No systemic involvement has been described. Skin biopsy reveals a focal increase in abnormal elastic tissue with abundant, wavy, fragmented and aggregated, basophilic elastic fibers in the reticular dermis.
Linear hypopigmentation and craniofacial asymmetry with acral, ocular and brain anomalies (ORPHA:589608)
A rare ectodermal dysplasia syndrome characterized by linear hypopigmentation and hypotrichosis following the lines of Blaschko, symmetric or asymmetric facial dysmorphism, and body asymmetry, in association with ocular, dental, and acral anomalies. Reported manifestations include microphthalmia, strabismus, myopia, oligodontia, microdontia, conical teeth, abnormal enamel, brachydactyly, syndactyly, and broad first toe, as well as dysmorphic facial features such as downslanting palpebral fissures, broad nasal bridge, malar hypoplasia, and microstomia. Brain imaging may show cystic leukoencephalopathy and ventricular dilation.