Isocromosoma 18q en mosaico: Caso clínico

background: the isochromosome 18q and chromosome 18 short arm deletion (18p-) constitute structural anomalies that are reported with certain frequency in the literature. however, the association of both abnormalities in a patient is very uncommon. objective: description of a clinical case of isochromosome 18 with emphasys in the few phenotypic manifestations. case-report: female infant 18 months-old, with short stature, minor dysmorphic features and a slight psychomotor developmental delay, whose chromosomal study in peripheral blood showed a chromosomal mosaicism with two cell lines: chromosome 18 long arm isochromosome and deletion of chromosome 18 short arm. the chromosomal analysis of both parents did not show numerical neither morphological alterations. discussion: this case illustrates the importance of requesting a karyotype in patients with small stature, dysmorphic features and/or malformations. the patient clinical features are compared with other similar cases described in the literature. the coexistence of both structural abnormalities (mosaicism) is extremely uncommon.