engleski

Molecular characterization of two patients with 9p-deletion

The clinical features of the 9p- deletion syndrome include dysmorphic facial features (trigonocephaly, midfacial hypoplasia, upward- slanting palpebral fissures, and long philtrum), cardiac anomalies, abnormal genitalia and moderate to severe mental retardation. The breakpoints usually occur in 9p22 to 9p24 region and majority of patients have either terminal deletion or translocation involving another chromosome. We present the cytogenetic and molecular analyses of two patients with 9p deletion resulting from unbalanced autosomal translocations. First patient is a 9-year-old girl with dysmorphic features, short neck, cerebral atrophy, tetraparesis, Sprengl anomaly, growth and psychomotor retardation. Routine cytogenetic analysis detected aberrant chromosome 9. Parental studies demonstrated that the father is a carrier of a balanced translocation involving chromosomes 4 and 9. The karyotype was designated as 46, XX, der (9) t (4 ; 9) (p14 ; p24) pat. The second patient is 11 month-old boy who presented with dysmorphic facial features, atrial septal defect, joint laxity, cryptorchid testes and hypotonia. Cytogenetic evaluation using high resolution G banding showed aberrant chromosome 9 in all metaphases. The patient inherited the derivative chromosome 9 from her mother. The designated karyotype was 46, XY, der(9)t(9 ; 16)(p22.1 ; 23.1)mat. Unbalanced chromosomal rearrangements were further evaluated by quantitative fluorescent-polymerase chain reaction (QF-PCR). Although both our patients had Del 9p-, they presented with variable phenotype demonstrating that a reliable genotype/phenotype correlation in monosomy 9p patients is difficult because of the different extent of the 9p deletion and presence of additional chromosome material in unbalanced reciprocal rearrangements.

9p; deletion

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