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Four small supernumerary marker chromosomes derived from chromosomes 6, 8, 11 and 12 in a patient with minimal clinical abnormalities: a case report

Joaquín Fernández-Toral1, Laura Rodríguez2, Ana Plasencia3, María Luisa Martínez-Frías4, Elisabeth Ewers5, Ahmed B Hamid5, Monika Ziegler5 and Thomas Liehr5*

Author Affiliations

1 Pediatría y jefe de sección de genética pediatrica del HUCA, Oviedo, Spain

2 AbaCid-Genética Hospital de Madrid Norte Sanchinarro, Madrid, Spain

3 Servicio de genética del HUCA. Oviedo, Spain

4 Estudio Colaborativo Español de Malformaciones Congénitas (ECEMC) del Centro de Investigación sobre Anomalías Congénitas (CIAC), Instituto de Salud Carlos III, Ministerio de Sanidad y Consumo, Madrid, Spain

5 Jena University Hospital, Institute of Human Genetics and Anthropology, Jena, Germany

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Journal of Medical Case Reports 2010, 4:239  doi:10.1186/1752-1947-4-239

Published: 3 August 2010



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.

Case presentation

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.


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.