Faculty Collaboration Database

A case of true hermaphroditism reveals an unusual mechanism of twinning. Hum Genet 2007 Apr;121(2):179-85

Date

12/14/2006

Pubmed ID

17165045

DOI

10.1007/s00439-006-0279-x

Scopus ID

2-s2.0-33947171960 (requires institutional sign-in at Scopus site)   43 Citations

Abstract

Traditionally twins are classified as dizygous or fraternal and monozygous or identical (Hall Twinning, 362, 2003 and 735-743). We report a rare case of 46,XX/46,XY twins: Twin A presented with ambiguous genitalia and Twin B was a phenotypically normal male. These twins demonstrate a third, previously unreported mechanism for twinning. The twins underwent initial investigation with 17-hydroxyprogesterone and testosterone levels, pelvic ultrasound and diagnostic laparoscopy. Cytogenetic analysis was performed on peripheral blood cells and skin fibroblasts. Histological examination and Fluorescence in situ hybridization studies on touch imprints were performed on gonadal biopsies. DNA analysis using more than 6,000 DNA markers was performed on skin fibroblast samples from the twins and on peripheral blood samples from both parents. Twin A was determined to be a true hermaphrodite and Twin B an apparently normal male. Both twins had a 46,XX/46,XY chromosome complement in peripheral lymphocytes, skin fibroblasts, and gonadal biopsies. The proportion of XX to XY cells varied between the twins and the tissues evaluated. Most significantly the twins shared 100% of maternal alleles and approximately 50% of paternal alleles in DNA analysis of skin fibroblasts. The twins are chimeric and share a single genetic contribution from their mother but have two genetic contributions from their father thus supporting the existence of a third, previously unreported type of twinning.

Author List

Souter VL, Parisi MA, Nyholt DR, Kapur RP, Henders AK, Opheim KE, Gunther DF, Mitchell ME, Glass IA, Montgomery GW

Author

Michael Ernst Mitchell MD Emeritus Professor in the Urology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

17-alpha-Hydroxyprogesterone
Chromosomes, Human, X
Chromosomes, Human, Y
Female
Fibroblasts
Genetic Linkage
Genetic Markers
Genitalia
Humans
Infant, Newborn
Male
Ovotesticular Disorders of Sex Development
Phenotype
Testosterone
Twins