Asplenia syndrome is one of the heterotaxy syndromes, which many familial and animal studies suggest are caused by the loss of adequate genetic control of normal left- right asymmetry development. Moreover, there has not been any environmental factor documented to cause these syndromes. Asplenia syndrome occurring in a pair of monozygotic twins is reported. In view of the negative family history, a new germline mutant gene might be the aetiology of our patients. Both twins are associated with some degree of discordant complex heart defects within the context of a high degree of “ mirror- image” of the unpaired thoracoabdominal organs. Conclusion: This report implies that sporadic asplenia syndrome might associate with new mutations and further genetic study may be indicated. These monozygotic twins’ discordant phenotypes imply that some unidentified factors play an important role in their ultimate development of the same genetically determined abnormalities.
Objective:To describe young monozy gotic twin sisters with fundus albipunctatus(a type of autosomal recessive sta-tionary night blindness caused by mu tations of the 11-cis retinol dehydrogenase geneRDH5)associated with cone dystrophy,previously reported in e lderly men.Methods:Ophthalmologic examinations were p erformed,and the RDH5gene was analyzed by direct genomic sequencing.Results:Twin 23-year-old sisters with high myopic refrac-tive errors of approximately -13dio pters were diagnosed as having fundus albipunctatus.Their photopic electroretino-graphic responses were markedly red uced,and cone dys-trophy was diagnosed.One twin had ma cular degeneration with reduced best-corrected visual acuity,while the other twin had normal maculae with good vis ual acuity.A com-pound heterozygous mutation,Val132Met and Arg280His,in the RDH5gene was found in both sisters.Conclusions:Cone dystrophy can be present in pati ents with fundus al-bipunctatus,not only elderly men bu t also young women.The clinical severity differed betw een monozygotic twins with fundus albipunctatus and cone d ystrophy.Clinical Relevance:The patients sex is not critical for the presence of cone dystrophy in patients with fu ndus albipunctatus.The discordant findings in the twins indicate that factors other than genetics influenced the p henotype.
Progressive facial hemiatrophy (PFH) is a ubiquitous disease, characterized by hyperpigmentation of the skin followed by unilateral craniofacial atrophy of su bcutaneous tissues, including fat, muscle and bone. Hereditary factors have been postulated to be involved in the aetiology of PFH. Yet, the occurrence of PFH i n one of two identicalmale twins reported heremakes this possibility unlikely. P FH usually occurs in the first two decades of life, and the clinical presentatio n resembles linear scleroderma. PFH may be complicated by autoimmune, neurologic al, ocular and dental disorders. Management of PFH comprises a long term follow -up of somatic disorders, and prevention of psychological problems. Treatment o f PFH is symptomatic and consists of plastic surgery after the disease activity has stopped. Conclusion: The occurrence of PFH in one of a monozygotic twin pair suggests that genetic factors are not involved in its aetiology. Early diagnosi s of PFH and accurate follow-up is essential to disclose the occurrence of comp lications.
