Maternal 2:18 chromosomal translocation manifesting as cause for developmental delay in a proband

Abstract

Developmental disabilities are a group of related chronic disorders of early onset and said to affect 5% to 10% children. Mental Retardation or intellectual disability has been redefined and replaced with Global developmental delay by WHO as the parameters of diagnosis of such a condition become valid and reliable by the age of five years of the proband. In Indian context the incidence is 2.5%.Chromosomal aberrations either structural or numerical account for 25-30% in general population. Chromosomal analysis and karyotyping is considered as primary investigation in management protocols of such children. Authors present a case of six months old child referred to cytogenetic laboratory with a clinical suspicion of delayed mile stone. Proband was born to a non-consanguineous couple delivered by lower segment caesarian section (LSCS) with no untoward incidents during intraoperative and post-operative phase of surgery. There was history of earlier fetal loss at third month of gestation due to cardiac defects diagnosed prenatally. Karyotyping of proband revealed 2:18 translocation. Karyotype of parents was done to find out the source of translocated chromosome. It was revealed that 2:18 translocated chromosome was seen in karyotype of mother of proband. Karyotype of proband was reported as 46,XX; der(18) t(2:18)(q31q35 ;q21q22)mat As per ISCN guidelines. Case has been reported for the rarity of such an occurrence.