alopecia

Rothmund-Thomson Syndrome

Clinical Characteristics
Ocular Features: 

Patients have been reported with juvenile and infantile cataracts.  Reported prevalence varies possibly because the diagnostic criteria have not been established and more than one disorder may be represented by the title.  Rothmund (an ophthalmologist) originally reported two families of 5 children in which lens opacities were found, but Thomson, who was a dermatologist, in a later report did not mention cataracts.  The lens opacities are usually nuclear or posterior cortical in location and may be evident in 50% of patients.  Iris stromal changes such as hypoplasia have also been reported.  Eyelashes and/or eyebrows may be sparse.  This is likely the same disorder as the previously described ‘mesodermal dysgenesis of the iris and skeletal dysplasia’ and formerly listed as 270240 in OMIM.

Systemic Features: 

This is a clinically heterogeneous disorder.  Skin atrophy with pigmentary changes, telangiectasia, short stature, premature aging, and skeletal abnormalities are characteristic.  There is an increased risk of malignancy, particularly osteosarcomas and skin cancer.  Saddle nose, sparse hair, hypogonadism, dysplastic nails, and teeth anomalies have also been described.

The skin is usually normal at birth but an erythematous rash typically appears in the first six months of life accompanied by swelling and blistering.  Eventually areas of hypo- and hyperpigmentation appear in a reticulated pattern with spots of punctate atrophy and telangiectasia.  Hyperkeratosis of the soles of the feet is common.  The skeletal abnormalities of dysplasia, radial ray defects, and missing bones are often evident at birth while osteopenia and delayed bone maturation are evident later.

Genetics

This is an autosomal recessive disorder in which most patients have mutations in the RECQL4 gene (8q24.3).

Mutations in the same gene cause Baller-Gerold syndrome (218600) suggesting that the two disorders are allelic but the phenotypes are considerably different.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

There is no treatment for the primary disorder but patients must be monitored for malignancies.  Visually significant cataracts should be removed.  It has been recommended that patients avoid excessive sun exposure to reduce the risk of skin cancers.

References
Article Title: 

Chondrodysplasia Punctata 2

Clinical Characteristics
Ocular Features: 

Early onset cataracts, often sectorial, are the major ocular feature of this syndrome.  Micropthalmia and microcornea have been observed.  There may be local vitreoretinal abnormalities leading to localized detachments and retinoschisis.

Systemic Features: 

The cartilage disease in this disorder leads to short stature that is often asymmetrical.  There is considerable variation in skeletal manifestations as the spine as well as the limbs can be involved.  The skin at birth may be scaly and erythrodermic.  Later the skin pigmentation may assume a whorled pattern and hyperkeratosis appears, often in a segmental pattern consistent with X-chromosomal mosaicism.  The skin may also be ichthyotic.  The nasal bridge is often flat with frontal bossing.  Flexion contractures are sometimes seen.  Cicatricial alopecia and coarse hair are often noted in adults.

Genetics

A number of skeletal disorders are classified as chondrodysplasia punctata, and there is considerable clinical and genetic heterogeneity (see also rhizomelic chondrodysplasia punctata [215100] in this database for an autosomal recessive form) which has yet to be worked out.  The disorder described here is an X-linked dominant disorder with lethality in males.  It results from a mutation in the EBP gene (Xp11.23-p11.22) causing difficulty in converting lanosterol to cholesterol.  The diagnosis can be confirmed by finding increased plasma accumulation of precursors of sterols 8(9)-cholestenol and 8-dehydrocholesterol. Rare severely affected males with hypotonia, seizures, cerebellar atrophy, agenesis of the corpus callosum, and developmental delays have been reported. 

The X-linked recessive (CDPX1;302950), autosomal dominant tibia-metacarpal (118651), and humero-metacarpal types are not associated with cataracts.

Pedigree: 
X-linked dominant, father affected
X-linked dominant, mother affected
Treatment
Treatment Options: 

Cataract extraction may improve vision.  Sun protection is advised.

References
Article Title: 

Incontinentia Pigmenti

Clinical Characteristics
Ocular Features: 

This is primarily a disorder of skin, teeth, hair, and the central nervous system but 35% of patients have important ocular features.  The iris is variably atrophic and has pigmentary anomalies often with posterior synechiae.  Nystagmus, strabismus, and limited vision are often present.  The majority (up to 90%) of individuals have significant retinal disease.  The retinal vascular pattern is anomalous with tortuosity in some areas and absence of vessels in others.  Preretinal fibrosis and retinal detachments may suggest the presence of a retinoblastoma.  Cataracts are common in patients who have a retinal detachment and some patients have microphthalmia. The retinal pigment epithelium is often abnormal with various-sized patches of sharply demarcated depigmentation.  Cases with uveitis, papillitis and chorioretinitis have been observed and it has been suggested that the observed retinal and choroidal changes result from prior inflammatory disease, perhaps even occurring in utero. There is a great deal of asymmetry in the clinical findings in the two eyes.

Systemic Features: 

Skin changes consisting of erythematous eruptions in a linear pattern are often present at birth and this may be followed by a verrucous stage.  The acute, early findings of inflammatory disease eventually subside, ultimately resulting in pigmentary changes that appear in a 'marbled pattern' in young adults.  Hypodontia and anodontia may be present.  Alopecia and CNS abnormalities are found in nearly half of patients.  Skeletal and structural deformities are common in patients with severe neurological deficits.  The only sign of this disorder in adult women may be a whorled pattern of scarring alopecia.

As many as 30% of patients have neurological features which may be present in the neonatal period.  Seizures of various types occur in 30% of patients.  MRI findings include periventricular and subcortical white matter changes, as well as corpus callosum hypoplasia, cerebral atrophy, and cerebellar hypoplasia.

 

Genetics

The majority of evidence suggests that this is an X-linked dominant disorder with lethality in males although sporadic cases occur.  The mutation occurs as a genomic rearrangement of the IKK-gamma gene, also known as NEMO (IKBKG) located at Xq28.  There is evidence from skin cultures that cells with the mutant X chromosome inactivated are preferentially viable.  It has been proposed that cells with the mutant bearing X chromosome as the active one are gradually replaced by those in which the normal X chromosome is active accounting for the post-natal course of the skin disease.

Pedigree: 
X-linked dominant, mother affected
Treatment
Treatment Options: 

No treatment for the generalized disorder is available although ocular surgery might be beneficial in rare cases with cataracts and detachments.

References
Article Title: 

Pages

Subscribe to RSS - alopecia