Through chromosomal karyotype analysis and chromosome microarray detection of a newborn with apnea and poor development, to explore the correlation between clinical etiology and chromosomal variation, and to evaluate the application value of traditional karyotype analysis and microarray chip technology in clinical practice.

Firstly, the peripheral blood chromosome G-banding karyotype analysis was performed in the children. Secondly, the chromosome microarray chip detection technology was used to accurately locate the variant fragments and identify the pathogenic genes.

The result of traditional karyotype analysis of the child was 46,X,add(15)(p13),+mar, considering the existence of sex chromosome abnormalities and autosomal imbalance variation in this karyotype. The results of the microarray chip showed that the patient conformed to the male karyotype, and there were partial duplications in the short arm of the X chromosome and the long arm of the Y chromosome.

The clinical etiology of this child is related to gene copy number variation. The partial duplication of the short arm of the X chromosome may be the main factor leading to sexual reversal and abnormal brain development in this child. And the apnea of the child is considered to be caused by abnormal brain development and neonatal pneumonia. The trraditional karyotype analysis has certain limitations, while microarray chip technology can accurately identify variant fragments and clarify disease-causing genes, which is of great diagnostic significance.