Partial monosomy 8q and partial trisomy 9q due to the maternal translocation t(8;9)(q24.3;q34.1): a case report: Partial trisomy 9q34-qter and partial monosomy 8q24.3-qter are very rare chromosomal abnormalities. Characteristic features of partial trisomy 9q34-qter are hypotonia, developmental delay, mild intellectual disability, dolichocephaly, distinct facial phenotype, long and thin fingers, and cardiac anomalies. Unlike the partial trisomy 9q34-qter, partial monosomy 8q24.3-qter has no distinct phenotype. Here we report a four years old female patient with partial trisomy 9q34-qter and partial monosomy 8q24.3-qter due to the maternal translocation t(8;9)(q24.3;q34.1). She has developmental delay, brachycephaly, facial dysmorphism, hand and foot anomalies, bilateral hearing loss, cardiac defect and abnormal brain MRI findings. To the best of our knowledge, this is the first report of the combination of partial trisomy 9q and partial monosomy 8q.