Small Marker Chromosome in a Pediatric Patient with Hypertelorism, Micropenis, Cryptorchidism and Congenital Heart Defects: A Case Report

Marker chromosomes are considered structurally abnormal, and phenotypes associated with these chromosomes are highly variable. Thus, these chromosomes can be characterized by classical and molecular cytogenetic analysis. Thus, we report the case on a patient from Manaus, Brazil with hypertelorism, micropenis, cryptorchidism and congenital heart disease, presenting karyotype 47,XY,+mar. The case was a 4-month-old male, born to unrelated parents, with no genetic history. The patient presented syndromic facies, low-set ears and an absence of the left duct, webbed neck, pre-auricular appendix, hypertelorism, micropenis, cryptorchidism and congenital heart disease. The result of the karyotype exam using G-banding revealed a karyotype 47,XY,+mar. The C-banding revealed markings in the pericentromeric regions of all chromosomes, with the marker chromosome being almost entirely heterochromatic. The patient died of sepsis, without having had cardiac surgery or molecular cytogenetic analysis. Classical cytogenetic analysis was essential for the identification of the marker chromosome in the karyotype of the reported patient, even if the complex chromosomal constitution was not identified. These analyses are essential to assist in diagnosis, and provide relevant information for prognosis and genetic counseling.