engleski

Partial trisomy 15q resulting from a familial pericentric inversion

Most cases of familial pericentric inversions are detected following the birth of an abnormal child owing to an unbalanced recombinant chromosome, forming after crossing-over in a meiotic inversion loop. Deletions or duplications of different but cytogenetically indistiguishable gene sequences are responsible for the different phenotypes. The patient, a 16-month-old boy, was reffered for an evaluation of multiple congenital anomalies. He was born at term by normal delivery to a 23 year-old mother and an unrelated 27 year-old father. Birth weight was 2700 g. height 45 cm and head circumference 30 cm. He had poor weight gain, hypotonia and bizzare convulsions starting in 1st month of life. Physical examination showed microcephaly, frontal bossing, apparently low-set ears, micrognathia, patent ductus arteriosus and undescended testes. Chromosome analysis with the high-resolution GTG banding study showed an extra light band on p-arm of chromosome 17 compatible with a partial duplication of chromosome 17p. Parental karyotype revealed pericentric inversion of chromosome 17 in the mother 46, XX, inv(17)(p13.3 q25.1). The origin of additional material attached to 17p was identified by FISH using the whole chromosome 17 painting probe and D17Z1/D17S379/RARA locus specific probes. Based on the hybridization signals of probes for MDS and PML loci, the patient has the duplication 17q recombinant, 46, XY, rec(17)dup(17q)inv(17)(p13.3 q25.1) mat This finding probably explains the couple´s history of three miscarrages, which may have been carriers of either of the possible unbalanced recombinant chromosomal configuration. The mother has relatively high risk of having other affected children. Prenatal diagnosis should be offered in future pregnancies.

Partial trisomy 17q; Pericentric inversion; FISH

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