But a fused clone isn't really a clone, it's a child. It is so because the child gets half of a set of the mother's genes and half of a set of the father's genes. This is why two parents can have children that don't look exactly alike - they're not clones.
But if a mother were to have her own child and was both the mother and father of that child, how do the alleles work?
Through meiosis we get haploid cells with only a certain subset of the single parent's genes. If you took two haploid cells from a single individual and managed to create a zygote, the resulting genetic material would only ever contain the parent's gene "Minus X" amount of their original genes. It'd be like having your mother's genes but missing a number of them. You'd instead have duplicates of certain alleles.
Take for example the presence of genes ABCDEFGH to simulate the parent's total genetic coding.
When meiosis occurs, the resulting haploid cell will, for example, have only ACEH as its contained genes. This would be the mother's egg. Taking her marrow and turning it into a sperm cell, the new haploid cell (more than likely), will not have the all other genes (BDFG), but rather will more likely be a different combination, such as CEFG. If these inseminate one another, you get the resulting zygote genetic code of ACCEEFGH.
Notice that both genes C and E are duplicated, and the zygote lacks the genes B and D entirely. Thus, it is not a clone.
This would obviously create a problem, as duplicate alleles (being of the same dominance) would be expressed equally, which would certainly lead to an increase in the production of certain proteins.