title: Four small supernumerary marker chromosomes derived from chromosomes 6, 8, 11 and 12 in a patient with minimal clinical abnormalities: a case report.
abstract: BACKGROUND
  Small supernumerary marker chromosomes are still a problem in cytogenetic diagnostic and genetic counseling. This holds especially true for the rare cases with multiple small supernumerary marker chromosomes. Most such cases are reported to be clinically severely affected due to the chromosomal imbalances induced by the presence of small supernumerary marker chromosomes. Here we report the first case of a patient having four different small supernumerary marker chromosomes which, apart from slight developmental retardation in youth and non-malignant hyperpigmentation, presented no other clinical signs.
  
  
  METHODS
  Our patient was a 30-year-old Caucasian man, delivered by caesarean section because of macrosomy. At birth he presented with bilateral cryptorchidism but no other birth defects. At age of around two years he showed psychomotor delay and a bilateral convergent strabismus. Later he had slight learning difficulties, with normal social behavior and now lives an independent life as an adult. Apart from hypogenitalism, he has multiple hyperpigmented nevi all over his body, short feet with pes cavus and claw toes. At age of 30 years, cytogenetic and molecular cytogenetic analysis revealed a karyotype of 50,XY,+min(6)(:p11.1-> q11.1:),+min(8)(:p11.1->q11.1:),+min(11)(:p11.11->q11:),+min(12)(:p11.2~12->q10:), leading overall to a small partial trisomy in 12p11.1~12.1.
  
  
  CONCLUSIONS
  Including this case, four single case reports are available in the literature with a karyotype 50,XN,+4mar. For prenatally detected multiple small supernumerary marker chromosomes in particular we learn from this case that such a cytogenetic condition may be correlated with a positive clinical outcome.
authors.affiliation: Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany. i8lith@mti.uni-jena.de.
authors.forename: Joaquín
authors.initials: J
authors.lastname: Fernández-Toral
authors.forename: Laura
authors.initials: L
authors.lastname: Rodríguez
authors.forename: Ana
authors.initials: A
authors.lastname: Plasencia
authors.forename: María Luisa
authors.initials: ML
authors.lastname: Martínez-Frías
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Ewers
authors.forename: Ahmed B
authors.initials: AB
authors.lastname: Hamid
authors.forename: Monika
authors.initials: M
authors.lastname: Ziegler
authors.forename: Thomas
authors.initials: T
authors.lastname: Liehr