title: Monozygotic twin girls with diploid/triploid chromosome mosaicism and cutaneous pigmentary dysplasia.
abstract: Diploid/triploid mosaicism is an uncommon clinical syndrome with a subtle but distinctive phenotype. Characteristic features include prenatal and postnatal asymmetric growth deficiency, triangular and/or asymmetric facies, micrognathia, finger and/or toe syndactyly, clinodactyly, single transverse palmar creases, male genital anomalies, hypotonia and psychomotor retardation. This disorder is underdiagnosed because in 70% of cases the triploid cell line is only seen in fibroblasts. In cases in which a triploid cell line is found in lymphocytes, it usually occurs in less than 5% of cells. While some reports of diploid/triploid mosaicism have mentioned unusual skin pigmentary patterns, including hypomelanosis of Ito, it was only recently recognized that this is a helpful diagnostic clue in mosaic chromosome disorders. We report monozygotic twin girls with diploid/triploid mosaicism whose cutaneous pigmentary dysplasia led to their diagnosis.
authors.affiliation: Clinical Genetics/Dysmorphology, National Naval Medical Center, Bethesda, Maryland.
authors.forename: E A
authors.initials: EA
authors.lastname: Wulfsberg
authors.forename: W C
authors.initials: WC
authors.lastname: Wassel
authors.forename: C A
authors.initials: CA
authors.lastname: Polo
mesh_terms: D000015:Abnormalities, Multiple / Q000175:diagnosis / Q000235:genetics; D002648:Child; D002869:Chromosome Aberrations / Q000175:diagnosis / Q000235:genetics*; D025063:Chromosome Disorders; D004171:Diploidy; D004200:Diseases in Twins / Q000175:diagnosis / Q000235:genetics*; D005146:Facial Asymmetry / Q000175:diagnosis / Q000235:genetics; D005260:Female; D006801:Humans; D008607:Intellectual Disability / Q000175:diagnosis / Q000235:genetics; D007621:Karyotyping; D009030:Mosaicism / Q000235:genetics*; D010641:Phenotype; D010859:Pigmentation Disorders / Q000175:diagnosis / Q000235:genetics*; D011123:Polyploidy; D014430:Twins, Monozygotic / Q000235:genetics