optic nerve edema

Majewski Syndrome

Clinical Characteristics
Ocular Features: 

No clinical information is available on the ocular features in this disorder.  The fundi have been described as normal in one patient but postmortem histopathology at 8 weeks revealed optic nerve edema with segmental axonal dropout and loss of myelin.  The nerve fiber layer of the retina was prominent with some proliferation of glial tissue.  Early nuclear sclerosis was also present.

Systemic Features: 

This disorder results from a dysgenesis of the cilia and is one of a group of short rib-polydactyly disorders.  Congenital anomalies are found in multiple organs including heart, lungs, skeleton, intestines, genitalia, pancreas, liver, and kidneys.  The diagnostic characteristic of SRPS type II is extreme shortening of the tibia in addition to short ribs in this type of short-limbed dwarfism.

Midline facial clefting, especially cleft lip, is common.  The epiglottis and lungs are often hypoplastic and the kidneys are polycystic.  Polydactyly and polysyndactyly of both pre- and postaxial types are usually present.  Most neonates with SRPS type II do not live beyond infancy.

Genetics

This is an autosomal recessive condition resulting from homozygous mutations in the NEK1 gene (4q33), or, rarely, from digenic biallelic mutations in NEK1 and DYNC2H1 (11q22.3).

Another condition with some of the same features leading to respiratory distress is asphyxiating thoracic dysplasia 1 (208500), or Jeune syndrome.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

No effective treatment is available for this condition but surgical treatment could be considered for specific anomalies.

References
Article Title: 

NEK1 mutations cause short-rib polydactyly syndrome type majewski

Thiel C, Kessler K, Giessl A, Dimmler A, Shalev SA, von der Haar S, Zenker M, Zahnleiter D, Stoss H, Beinder E, Abou Jamra R, Ekici AB, Schroder-Kress N, Aigner T, Kirchner T, Reis A, Brandst?SStter JH, Rauch A. NEK1 mutations cause short-rib polydactyly syndrome type majewski. Am J Hum Genet. 2011 Jan 7;88(1):106-14.

PubMed ID: 
21211617

Optic Nerve Edema, Splenomegaly, Cytopenias

Clinical Characteristics
Ocular Features: 

Persistent optic nerve edema is eventually followed by some degree of optic atrophy.  The nerve edema may be seen early in the first decade of life and is not associated with increased lumbar puncture pressure.  Peripapillary hemorrhages may be seen.  Visual acuity may decrease somewhat by the end of the first decade of life and becomes functionally significant in early adolescence and may be reduced to counting fingers.  The ERG, which shows minimal dysfunction early, eventually appears nearly flat without photopic or scotopic responses.  The retinal vessels become markedly attenuated and the macula may be mildly edematous and show pigmentary changes.  Pigment clumping is not seen.  Visual fields show a central or cecocentral scotoma, enlargement of the blind spot, and eventually severe peripheral constriction.  The vitreous and aqueous humor sometimes have an increased number of cells.   Lenticular opacities requiring cataract surgery has been reported.  One patient developed a phacomorphic angle closure attack at the age of 19 years.

Systemic Features: 

Splenomegaly is a consistent sign and is usually present in the first decade of life but histology shows primarily cellular congestion of the red pulp cords.  Bone marrow biopsies show mild erythroid hyperplasia. Peripheral blood counts show mild neutropenia and thrombocytopenia.  Occasional atypical lymphocytes may be seen.  Patients often complain of mildly to moderately severe migraine headaches.  Urticaria and anhidrosis are common features.

Genetics

Only a single report of this condition has been published.  A mother and two daughters (half sisters) had the symptoms described here and this is the basis for consideration of autosomal dominant inheritance.  Nothing is known regarding the etiology or the mechanism of disease.

Pedigree: 
Autosomal dominant
Treatment
Treatment Options: 

Topical, intravitreal, oral, and subtenon application of steroids apparently have no impact on the progression of the intraocular disease.  Cataracts may need to be removed.

References
Article Title: 

An inherited disorder with splenomegaly, cytopenias, and vision loss

Tantravahi SK, Williams LB, Digre KB, Creel DJ, Smock KJ, Deangelis MM, Clayton FC, Vitale AT, Rodgers GM. An inherited disorder with splenomegaly, cytopenias, and vision loss. Am J Med Genet A. 2012 Mar;158A(3):475-81. doi: 10.1002/ajmg.a.34437. Epub 2012 Feb 3.

PubMed ID: 
22307799
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