Erika P. Tardy

Prenatal exclusion of segmental trisomy in familial chromosome 21 pericentric inversion by fluorescence in situ hybridization.

We report the prenatal exclusion of partial trisomy in a family with maternal pericentric inversion of chromosome 21 by fluorescence in situ hybridization (FISH). After determining the structural rearrangement in the mother and her affected son with 46,XY,rec(21)dup(21q)inv(21)(p11q22) resulting in Down syndrome (DS), a chorionic villus sample from the current pregnancy was analysed for the copy number of the DS critical region with a cosmid contig. The signal distribution was normal and the cytogenetic analysis revealed that the fetus had inherited the inverted chromosome 21 in a balanced form. FISH probes specific for the DS region are of great value in supporting cytogenetic results, regardless of the structural status of chromosome 21.

Mixed gonadal dysgenesis associated with an isodicentric Y chromosome

Authors report a case of mixed gonadal dysgenesis with a karyotype containing an isodicentric Y chromosome in mosaic form, which was diagnosed in an infant. They emphasize the necessity of the special investigations of newborn with perineoscrotal hypospadia and bilateral or unilateral maldescent testes immediately after birth. The result of accurate evaluation provides correct sex assignment and the prevention of the neoplastic degeneration of a dysgenetic gonad.

Fluorescence in situ hybridization of chorionic interphase cells for prenatal screening of Down syndrome

OBJECTIVE Our purpose was to determine the usefulness and reliability of fluorescence in situ hybridization on interphase chorionic villi cells in the prenatal diagnosis of Down syndrome. METHODS A total of 336 samples of chorionic villi were analysed by direct chromosome preparation and FISH with a DNA probe specific to chromosome 21. The samples were obtained as part of the routine obstetric investigation and management. RESULTS The sampling and direct karyotyping was successful in all cases. At least 50 cells were valuable by FISH in 331 of 336 samples. Both methods showed Down syndrome in 12 cases. The follow-up investigations showed that there was no false-negative or false-positive result following these procedures. CONCLUSION Based on these results and the fact that it is possible to analyse by interphase FISH at least ten times more cells than by conventional cytogenetic methods, and these cells originate from different tissues of chorionic villi, it is concluded that FISH increases the reliability of the diagnosis. Nevertheless, more data are needed for correct statistical analysis. Since this method is cheaper and gives diagnosis earlier than cell culture, the combination of direct chromosome preparation and FISH on chorionic villi is offered for prenatal Down syndrome screening.

Praenatalisan diagnosztizált Pallister–Killian-szindróma esete

Pallister-Killian syndrome (PKS) is a rare, sporadic genetic disorder that is caused by the mosaic presence of a supernumerary marker chromosome, isochromosome 12p. The syndrome is a polydysmorphic condition characterized by mental retardation, craniofacial dysmorphism, hypotonia, seizures, epilepsy and certain organic malformations (diaphragmatic hernia, congenital heart disease). Prenatal diagnosis is challenging due to the mosaic tissue-specific distribution of the chromosomal disorder and highly variable phenotype. Prenatal diagnosis is often accidental, however, appropriate laboratory techniques based on the second trimester ultrasound anomalies provide accurate prenatal diagnosis. We report a case of a 36-year-old primipara with second trimester ultrasound markers (polyhydramnion, ventriculomegaly, rhizomelic micromelia, abnormal facial profile). The patient underwent amniocentesis, the conventional karyotyping revealed a supernumerary chromosome in nearly 50 percent of amniocytes. FISH and targeted multicolour FISH probes verified mosaic tetrasomy of the short arm of chromosome 12 of the fetus. Fetopathological examinations and analysis of fetal tissues and blood confirmed the prenatal diagnosis. To our knowledge, this is the first reported case of prenatally diagnosed Pallister-Killian syndrome in Hungary. Orv Hetil. 2018; 159(21): 847-852.Pallister-Killian syndrome (PKS) is a rare, sporadic genetic disorder that is caused by the mosaic presence of a supernumerary marker chromosome, isochromosome 12p. The syndrome is a polydysmorphic condition characterized by mental retardation, craniofacial dysmorphism, hypotonia, seizures, epilepsy and certain organic malformations (diaphragmatic hernia, congenital heart disease). Prenatal diagnosis is challenging due to the mosaic tissue-specific distribution of the chromosomal disorder and highly variable phenotype. Prenatal diagnosis is often accidental, however, appropriate laboratory techniques based on the second trimester ultrasound anomalies provide accurate prenatal diagnosis. We report a case of a 36-year-old primipara with second trimester ultrasound markers (polyhydramnion, ventriculomegaly, rhizomelic micromelia, abnormal facial profile). The patient underwent amniocentesis, the conventional karyotyping revealed a supernumerary chromosome in nearly 50 percent of amniocytes. FISH and targeted multicolour FISH probes verified mosaic tetrasomy of the short arm of chromosome 12 of the fetus. Fetopathological examinations and analysis of fetal tissues and blood confirmed the prenatal diagnosis. To our knowledge, this is the first reported case of prenatally diagnosed Pallister-Killian syndrome in Hungary. Orv Hetil. 2018; 159(21): 847-852.

Izodicentrikus Y-kromoszómához társuló kevert gonáddiszgenezis [Mixed gonadal dysgenesis associated with an isodicentric Y chromosome]

Authors report a case of mixed gonadal dysgenesis with a karyotype containing an isodicentric Y chromosome in mosaic form, which was diagnosed in an infant. They emphasize the necessity of the special investigations of newborn with perineoscrotal hypospadia and bilateral or unilateral maldescent testes immediately after birth. The result of accurate evaluation provides correct sex assignment and the prevention of the neoplastic degeneration of a dysgenetic gonad.

Izodicentrikus Y-kromoszómához társuló kevert gonáddiszgenezis

Authors report a case of mixed gonadal dysgenesis with a karyotype containing an isodicentric Y chromosome in mosaic form, which was diagnosed in an infant. They emphasize the necessity of the special investigations of newborn with perineoscrotal hypospadia and bilateral or unilateral maldescent testes immediately after birth. The result of accurate evaluation provides correct sex assignment and the prevention of the neoplastic degeneration of a dysgenetic gonad.