Trisomy 21 and Rett syndrome: a double burden.

Trisomy 21 with 47,+18 lymphocyte cell line: double mitotic nondisjunction.

A patient with Down's syndrome was found to have 47,XX,+18/47,XX,+21 mosaicism. Chromosome 18 trisomy was found only in 18% of lymphocytes and not in skin fibroblasts. A likely interpretation is double nondisjunction in a single lymphocyte precursor of a trisomy 21 embryo. A brief review of other cases of mitotic multiple nondisjunction and double aneuploid mosiacism is presented.

Triple-X Syndrome in a Trisomic Down Syndrome Child: Both Aneuploidies Originated from the Mother

Here we report a case of double aneuploidy showing trisomy 21 and triple-X chromosome in a case of Down syndrome born to young non-consanguineous parents. The child presented with strabismus, periorbital swelling, scanty eyebrows and microganthia in addition to Down features. Molecular characterization has shown the maternal origin of double aneuploidy with trisomy 21 at meiosis-II and triple-X...

Down syndrome child with 48,XXY,+21 karyotype

Cytogenetic analysis in 60 clinically suspected cases of Down syndrome and their parents was carried out using conventional Giemsa–trypsin-banding technique. Fifty-five individuals (91%) exhibited a free trisomy 21. Robertsonian translocations were seen in three cases and two cases exhibited a normal karyotype. A four-month-old child, the second-born of non-consanguineous parents, possessed an ...

Double partial trisomy 9q34.1-->qter and 21pter-->q22.11: FISH and clinical findings.

We describe a patient with double trisomy 9q34.1-->qter and 21pter-->q22.1 resulting from 3:1 segregation of a maternal balanced translocation. The patient shows a clinical syndrome similar to that observed in patients with duplication of the chromosome 9q distal region, while no signs of trisomy 21 were observed. The use of high resolution banding and FISH were of fundamental importance for th...

Double autosomal trisomy and mosaicism for chromosomes no. 8 and no. 21.