The inheritance of two copies of an identical chromosome is known as isodisomy
, and results in whole chromosome ROH.
However, the presence of the same paternal haploid complement in both cell lines suggests paternal uniparental isodisomy
and involvement of only a single egg and sperm nucleus.
In one patient with classic TIOD, a homozygous deletion in exon 14 appeared to have resulted from partial maternal isodisomy
of the short arm of chromosome 2 carrying the defective TPO gene (Bakker et al.