Here some basic information on sSMC in general is summarized:

It is explained:

- what sSMC are,

- what effects they have,

- when the first sSMC was seen,

- what happens if genetic relevant material (euchromatin) is present on the sSMC,

- what is known about mosaicism in sSMC,

- what is known on sSMC in connection with uniparental disomy (UPD),

- which synonyms are used for sSMC,

- in which frequencies sSMC appear,

- and what is known on the way of their formation.