acanthosis nigricans

Beare-Stevenson Syndrome

Clinical Characteristics
Ocular Features: 

The midface hypoplasia and shallow orbits result in the appearance of prominent eyes.  Ptosis and hypertelorism have been reported while the palpebral fissures are downslanting. One patient has been reported to have optic atrophy.  Another patient was described with cloudy corneas, irregular irides and nonreactive pupils.

Systemic Features: 

Pregnancies may be complicated by polyhydramnios.  Infants are born with craniosynostosis with a cloverleaf pattern usually.  The skull is often shortened in the anteroposterior axis with flattening of the occipital region.  The skin is deeply furrowed with the cutis gyrata patterns most prominent in the posterior scalp but also present on the palms, soles, pinnae, and elsewhere.  Acanthosis nigricans is often present.

There is midface hypoplasia and nearly all individuals have intellectual disability.

The external ear canals can be atretic, the nares are often anteverted, and the mouth may be small.  An excess number of neonatal teeth and hypoplastic nails have been noted.  Hydrocephalus is common.  The umbilical stump is often unusually prominent.  Anogenital anomalies such as an anteriorly placed anus, cryptorchidism, and bifid scrotum may be present.  Pyloric stenosis is sometimes present.

Upper airway obstruction with respiratory distress may necessitate a tracheotomy. A cartilaginous tracheal sleeve replacing the normal C rings of cartilage has been found in several infants. These can be difficult to detect and their presence may have been responsible for breathing restrictions that has led to the demise of some children before two years of age.

Genetics

Reported cases have occurred sporadically.  Increased paternal age has been suggested as a factor in the occurrence of heterozygous mutations in the FGFR2 gene (10q26.13) which have been identified in some individuals.

Other forms of craniosynostosis in which mutations in FGFR2 have been found are: Crouzon Syndrome (123500), Pfeiffer Syndrome (101600), Apert Syndrome (101200), Jackson-Weiss Syndrome (123150), and Saethre-Chotzen Syndrome (101400).

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

There is no general treatment for this syndrome.  Several infants have had tracheotomies and CNS shunts.

References
Article Title: 

Beare-Stevenson cutis gyrata syndrome

Hall BD, Cadle RG, Golabi M, Morris CA, Cohen MM Jr. Beare-Stevenson cutis gyrata syndrome. Am J Med Genet. 1992 Sep 1;44(1):82-9. PubMed PMID: 1519658.

PubMed ID: 
1519658

Retinitis Pigmentosa, Deafness, Mental Retardation and Hypogonadism

Clinical Characteristics
Ocular Features: 

Only two families with this presumed disorder have been reported.  The retinal picture resembles retinitis pigmentosa with ‘bone spicule’ pigment clumps, vascular attenuation, and pale optic nerve heads.  Cataracts and nystagmus have been observed.  Vision is usually limited to light perception by the middle of the first decade of life.

Systemic Features: 

Small testes and gynecomastia are found in males while females have oligo- or amenorrhea.  The hands and feet appear broad and the face has a coarse appearance with a depressed nasal bridge and a broad nose.  Insulin-resistant diabetes and hyperinsulinemia are present.  Acanthosis nigricans, keloids, obesity, and hearing loss are also features.  All patients have significant developmental delays and evident mental retardation.

Genetics

No locus has been identified although autosomal recessive inheritance seems likely: the parents in one family were first cousins and there was no parent to child transmission.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

There is no effective treatment although cataract surgery might be considered if lens opacities are visually significant.

References
Article Title: 
Subscribe to RSS - acanthosis nigricans