OBJECTIVE: To ascertain the karyotype of a girl with moderate mental retardation and growth retardation, perform correlation analysis between chromosomal variation and phenotype, and investigate the application and superiority of array-based comparative genomic hybridization (array-CGH) in clinical cytogenetic diagnosis. METHODS: G-banded chromosome analysis, array-CGH, fluorescence in situ hybridization (FISH) and real-time quantitative PCR (RQ-PCR) were used to ascertain the karyotype of the patient and her relatives. RESULTS: G-banding analysis of the patient showed a derivative chromosome 10 with an extra fragment on its long arm terminal, both her father and grandmother had an apparently balanced translocation t(4;10)(q25;q26). Array-CGH revealed that the breakpoint on chromosome 4 was located at 4q26. In addition, a microdeletion of about 0.54 Mb del(10)(q26.3) was identified from the patient. FISH and RQ-PCR confirmed that the del(10)(q26.3) was also present in both her father and grandmother. CONCLUSION: No recognizable phenotype was associated with del(10)(q26.3). The abnormal phenotypes presented in the patient may be ascribed to the 4q26-q35.2 triplication. Further more, compared with conventional cytogenetic analysis, array-CGH is of high resolution and high accuracy.
OBJECTIVE: To ascertain the karyotype of a girl with moderate mental retardation and growth retardation, perform correlation analysis between chromosomal variation and phenotype, and investigate the application and superiority of array-based comparative genomic hybridization (array-CGH) in clinical cytogenetic diagnosis. METHODS: G-banded chromosome analysis, array-CGH, fluorescence in situ hybridization (FISH) and real-time quantitative PCR (RQ-PCR) were used to ascertain the karyotype of the patient and her relatives. RESULTS: G-banding analysis of the patient showed a derivative chromosome 10 with an extra fragment on its long arm terminal, both her father and grandmother had an apparently balanced translocation t(4;10)(q25;q26). Array-CGH revealed that the breakpoint on chromosome 4 was located at 4q26. In addition, a microdeletion of about 0.54 Mb del(10)(q26.3) was identified from the patient. FISH and RQ-PCR confirmed that the del(10)(q26.3) was also present in both her father and grandmother. CONCLUSION: No recognizable phenotype was associated with del(10)(q26.3). The abnormal phenotypes presented in the patient may be ascribed to the 4q26-q35.2 triplication. Further more, compared with conventional cytogenetic analysis, array-CGH is of high resolution and high accuracy.