engleski

Partial monosomy 18p : cytogenetic and clinical presentation in four patients

Partial monosomy 18p is considered the second most frequently occurring autosomal deletion. This deletion occur de novo in about 85% of patients, and in 15% of cases is a result of a segregation of familial rearrangements. Most reported cases are due to terminal deletion of short arm. Occasionally deletion of the long and the short arm with fusion of the ends results in ring chromosome. The pehnotype is highly variable and depends on the extent of deletion. We present the results of cytogenetic and clinical evaluation in four patients with partial monosomy of 18p. First patient is 8 years old girl with facial dysmorphism and mild mental retardation. Cytogenetic analysis revealed aberrant karyotype with 45 chromosomes, missing chromosomes 15 and 18, and the presence of the rearranged chromosome. Banding pattern and flueorescence in situ hybridization (FISH) analysis showed that aberrant chromosome was composed of the long arms of chromosomes 15 and 18, with the presence of the centromeric region of both chromosomes involved. Second patient is 3 months old girl with mild dysmorphic traits and congenital heart defect. Cytogenetic studes showed a karyotype with 46 chromosomes missing whole short arm of chromosome 18. Third patient is 2 years old girl with dysmorphic face, cleft lip and palate (CLP) and developmental delay. Classical cytogenetics identified ring chromosome 18(p11.2 ; q23). Fourth patient is 9 years old boy with dysmorphic traits, cleft palate (CP) and mental and growth retardation. Routine cytogenetic studies demonstrated a mosaic karyotype 46, XY, r(18)(p11.3q22)/46, XY. Clinical presentation in our patients is compared with the literature data on patients with identical genotype.

monosomy 18p; cytogenetics; clinical presentation

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