Pseudoxanthoma Elasticum-Like Disease

Clinical Characteristics
Ocular Features: 

Retinitis pigmentosa has been diagnosed clinically and confirmed by ERG studies in some patients. The fundi in a few individuals have the typical angioid streaks and/or peau d’orange changes. The impact on visual acuity and its prognosis has not been systematically studied.

Systemic Features: 

The skin changes resulting from fragmentation and aberrant mineralization of connective tissue, particularly elastic fibers, resemble those seem in classic pseudoxanthoma elasticum. These include the presence of yellowish papules or leathery plaques with dot-like depressions (‘chicken skin’). However, the skin changes are more widespread and involve trunk as well as limbs and flexural areas. Ultrastructurally the elastic fibers are more severely fragmented than those in classic PXE.

Many patients in addition have deficiencies in vitamin K-dependent clotting factors such as II, VII, IX, and X. Epistaxis, spontaneous gingival bleeding and severe vaginal hemorrhages may occur. Cerebral aneurysms, vascular occlusions, and atherosclerotic plaques in the lower extremities have been reported in a few patients.

Genetics

Classic pseudoxanthoma elasticum is due to homozygous mutations in the ABCC6 (ATP-binding cassette subfamily C member 6) gene. However, in the PXE-like condition described here homozygous or compound heterozygous mutations in the GGCX (gamma-glutamyl carboxylase) gene (2p11.2) are responsible. Some heterozygous GGCX individuals in families with this genotype who are also heterozygous for ABCC6 mutations (doubly heterozygous) may have similar skin features. Thus the condition described here may also be a digenic disorder in some individuals.

Pseudoxanthoma elasticum-like disease is an autosomal recessive disorder.

Treatment
Treatment Options: 

There is no treatment for the connective tissue defect but individual problems such as subretinal neovascularization, hemorrhages, and vascular occlusions may respond to appropriate therapy.

References
Article Title: 

References

Kariminejad A, Bozorgmehr B, Najafi A, Khoshaeen A, Ghalandari M, Najmabadi H, Hasan Kariminejad M, Vanakker OM, Hosen MJ, Malfait F, Quaglino D, Florijn RJ, Bergen AA, Hennekam RC. Retinitis Pigmentosa, Cutis Laxa and Pseudoxanthoma Elasticum-Like Skin Manifestations Associated with GGCX Mutations. J Invest Dermatol. 2014 Apr 16. [Epub ahead of print].

PubMedID: 24739904

Li Q, Grange DK, Armstrong NL, Whelan AJ, Hurley MY, Rishavy MA, Hallgren KW, Berkner KL, Schurgers LJ, Jiang Q, Uitto J. Mutations in the GGCX and ABCC6 genes in a family with pseudoxanthoma elasticum-like phenotypes. J Invest Dermatol. 2009 Mar;129(3):553-63.

PubMedID: 18800149

Vanakker OM, Martin L, Gheduzzi D, Leroy BP, Loeys BL, Guerci VI, Matthys D, Terry SF, Coucke PJ, Pasquali-Ronchetti I, De Paepe A. Pseudoxanthoma elasticum-like phenotype with cutis laxa and multiple coagulation factor deficiency represents a separate genetic entity. J Invest Dermatol. 2007 Mar;127(3):581-7.

PubMedID: 17110937