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Complex small supernumerary marker chromosomes - an update.

Liehr T, Cirkovic S, Lalic T, Guc-Scekic M, de Almeida C, Weimer J, Iourov I, Melaragno MI, Guilherme RS, Stefanou EG, Aktas D, Kreskowski K, Klein E, Ziegler M, Kosyakova N, Volleth M, Hamid AB - Mol Cytogenet (2013)

Bottom Line: As yet three complex-sSMC-associated syndromes are identified.As recurrent breakpoints in the complex sSMC were characterized, it is to be expected that more syndromes are identified in this subgroup of sSMC.Overall, complex sSMC emphasize once more the importance of detailed cytogenetic analyses, especially in patients with idiopathic mental retardation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, Jena D-07743, Germany ; Institut für Humangenetik, Postfach, Jena D-07740, Germany.

ABSTRACT

Background: Complex small supernumerary marker chromosomes (sSMC) constitute one of the smallest subgroups of sSMC in general. Complex sSMC consist of chromosomal material derived from more than one chromosome; the best known representative of this group is the derivative chromosome 22 {der(22)t(11;22)} or Emanuel syndrome. In 2008 we speculated that complex sSMC could be part of an underestimated entity.

Results: Here, the overall yet reported 412 complex sSMC are summarized. They constitute 8.4% of all yet in detail characterized sSMC cases. The majority of the complex sSMC is contributed by patients suffering from Emanuel syndrome (82%). Besides there are a der(22)t(8;22)(q24.1;q11.1) and a der(13)t(13;18)(q11;p11.21) or der(21)t(18;21)(p11.21;q11.1) = der(13 or 21)t(13 or 21;18) syndrome. The latter two represent another 2.6% and 2.2% of the complex sSMC-cases, respectively. The large majority of complex sSMC has a centric minute shape and derives from an acrocentric chromosome. Nonetheless, complex sSMC can involve material from each chromosomal origin. Most complex sSMC are inherited form a balanced translocation in one parent and are non-mosaic. Interestingly, there are hot spots for the chromosomal breakpoints involved.

Conclusions: Complex sSMC need to be considered in diagnostics, especially in non-mosaic, centric minute shaped sSMC. As yet three complex-sSMC-associated syndromes are identified. As recurrent breakpoints in the complex sSMC were characterized, it is to be expected that more syndromes are identified in this subgroup of sSMC. Overall, complex sSMC emphasize once more the importance of detailed cytogenetic analyses, especially in patients with idiopathic mental retardation.

No MeSH data available.


Related in: MedlinePlus

Complex sSMC: frequencies, shapes, origin and mosaicism. A) Schematic depictions of the three yet known complex sSMC leading to specific syndromic conditions: the Emanuel = der(22)t(11;22), the der(22)t(8;22) and the der(13 or 21)(13 or 21;18) syndrome. B) Frequency of the known three syndromes from A) and the other complex sSMC (others) depicted as a ring diagram. C) Distribution of the sSMC shapes among the reported complex sSMC cases excluding the cases with Emanuel syndrome. D) Distribution of de novo and inherited cases among complex sSMC excluding the cases with Emanuel syndrome. E) Complex sSMC tended to be mosaic only among the de novo cases.
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Figure 1: Complex sSMC: frequencies, shapes, origin and mosaicism. A) Schematic depictions of the three yet known complex sSMC leading to specific syndromic conditions: the Emanuel = der(22)t(11;22), the der(22)t(8;22) and the der(13 or 21)(13 or 21;18) syndrome. B) Frequency of the known three syndromes from A) and the other complex sSMC (others) depicted as a ring diagram. C) Distribution of the sSMC shapes among the reported complex sSMC cases excluding the cases with Emanuel syndrome. D) Distribution of de novo and inherited cases among complex sSMC excluding the cases with Emanuel syndrome. E) Complex sSMC tended to be mosaic only among the de novo cases.

Mentions: The 412 complex sSMC available in literature constitute 8.4% of all yet in detail characterized sSMC cases. The majority of the complex sSMC cases is contributed by der(22)t(11;22)(q23;q11.2) cases, i.e. 339/412 cases (82%). Besides there are two additional types of complex sSMC which have been observed in more than 2 independent patients: the der(22)t(8;22)(q24.1;q11.1) and the der(13)t(13;18)(q11;p11.21) or der(21)t(18;21)(p11.21;q11.1) = der(13 or 21)t(13 or 21;18) (Figure 1A). Both represent another 2.6% and 2.2% of complex sSMC-cases (Figure 1B).


Complex small supernumerary marker chromosomes - an update.

Liehr T, Cirkovic S, Lalic T, Guc-Scekic M, de Almeida C, Weimer J, Iourov I, Melaragno MI, Guilherme RS, Stefanou EG, Aktas D, Kreskowski K, Klein E, Ziegler M, Kosyakova N, Volleth M, Hamid AB - Mol Cytogenet (2013)

Complex sSMC: frequencies, shapes, origin and mosaicism. A) Schematic depictions of the three yet known complex sSMC leading to specific syndromic conditions: the Emanuel = der(22)t(11;22), the der(22)t(8;22) and the der(13 or 21)(13 or 21;18) syndrome. B) Frequency of the known three syndromes from A) and the other complex sSMC (others) depicted as a ring diagram. C) Distribution of the sSMC shapes among the reported complex sSMC cases excluding the cases with Emanuel syndrome. D) Distribution of de novo and inherited cases among complex sSMC excluding the cases with Emanuel syndrome. E) Complex sSMC tended to be mosaic only among the de novo cases.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4129180&req=5

Figure 1: Complex sSMC: frequencies, shapes, origin and mosaicism. A) Schematic depictions of the three yet known complex sSMC leading to specific syndromic conditions: the Emanuel = der(22)t(11;22), the der(22)t(8;22) and the der(13 or 21)(13 or 21;18) syndrome. B) Frequency of the known three syndromes from A) and the other complex sSMC (others) depicted as a ring diagram. C) Distribution of the sSMC shapes among the reported complex sSMC cases excluding the cases with Emanuel syndrome. D) Distribution of de novo and inherited cases among complex sSMC excluding the cases with Emanuel syndrome. E) Complex sSMC tended to be mosaic only among the de novo cases.
Mentions: The 412 complex sSMC available in literature constitute 8.4% of all yet in detail characterized sSMC cases. The majority of the complex sSMC cases is contributed by der(22)t(11;22)(q23;q11.2) cases, i.e. 339/412 cases (82%). Besides there are two additional types of complex sSMC which have been observed in more than 2 independent patients: the der(22)t(8;22)(q24.1;q11.1) and the der(13)t(13;18)(q11;p11.21) or der(21)t(18;21)(p11.21;q11.1) = der(13 or 21)t(13 or 21;18) (Figure 1A). Both represent another 2.6% and 2.2% of complex sSMC-cases (Figure 1B).

Bottom Line: As yet three complex-sSMC-associated syndromes are identified.As recurrent breakpoints in the complex sSMC were characterized, it is to be expected that more syndromes are identified in this subgroup of sSMC.Overall, complex sSMC emphasize once more the importance of detailed cytogenetic analyses, especially in patients with idiopathic mental retardation.

View Article: PubMed Central - HTML - PubMed

Affiliation: Jena University Hospital, Friedrich Schiller University, Institute of Human Genetics, Kollegiengasse 10, Jena D-07743, Germany ; Institut für Humangenetik, Postfach, Jena D-07740, Germany.

ABSTRACT

Background: Complex small supernumerary marker chromosomes (sSMC) constitute one of the smallest subgroups of sSMC in general. Complex sSMC consist of chromosomal material derived from more than one chromosome; the best known representative of this group is the derivative chromosome 22 {der(22)t(11;22)} or Emanuel syndrome. In 2008 we speculated that complex sSMC could be part of an underestimated entity.

Results: Here, the overall yet reported 412 complex sSMC are summarized. They constitute 8.4% of all yet in detail characterized sSMC cases. The majority of the complex sSMC is contributed by patients suffering from Emanuel syndrome (82%). Besides there are a der(22)t(8;22)(q24.1;q11.1) and a der(13)t(13;18)(q11;p11.21) or der(21)t(18;21)(p11.21;q11.1) = der(13 or 21)t(13 or 21;18) syndrome. The latter two represent another 2.6% and 2.2% of the complex sSMC-cases, respectively. The large majority of complex sSMC has a centric minute shape and derives from an acrocentric chromosome. Nonetheless, complex sSMC can involve material from each chromosomal origin. Most complex sSMC are inherited form a balanced translocation in one parent and are non-mosaic. Interestingly, there are hot spots for the chromosomal breakpoints involved.

Conclusions: Complex sSMC need to be considered in diagnostics, especially in non-mosaic, centric minute shaped sSMC. As yet three complex-sSMC-associated syndromes are identified. As recurrent breakpoints in the complex sSMC were characterized, it is to be expected that more syndromes are identified in this subgroup of sSMC. Overall, complex sSMC emphasize once more the importance of detailed cytogenetic analyses, especially in patients with idiopathic mental retardation.

No MeSH data available.


Related in: MedlinePlus