Siblings with opposite chromosome constitutions, dup(2q)/del(7q) and del(2q)/dup(7q)

• Chromosome 7q36 and 2q37.2 microdeletion syndromes are rare genomic disorders.
• We found two brothers with subtelomeric abnormalities on the same sites.
• One had 2q37.2 dup and 7q36 del, and the other had 2q37.2 del and 7q36 dup.
• They presented a variety of abnormal features clinically.
• We compared them to each other and with previously reported cases.

Chromosome 7q36 microdeletion syndrome is a rare genomic disorder characterized by underdevelopment of the brain, microcephaly, anomalies of the sex organs, and language problems. Developmental delay, intellectual disability, autistic spectrum disorders, BDMR syndrome, and unusual facial morphology are the key features of the chromosome 2q37 microdeletion syndrome. A genetic screening for two brothers with global developmental delay using high-resolution chromosomal analysis and subtelomeric multiplex ligation-dependent probe amplification revealed subtelomeric rearrangements on the same sites of 2q37.2 and 7q35, with reversed deletion and duplication. Both of them showed dysmorphic facial features, severe disability of physical and intellectual development, and abnormal genitalia with differential abnormalities in their phenotypes. The family did not have abnormal genetic phenotypes. According to the genetic analysis of their parents, adjacent-1 segregation from their mother's was suggested as a mechanism of their gene mutation. By comparing the phenotypes of our patients with previous reports on similar patients, we tried to obtain the information of related genes and their chromosomal locations.