16 research outputs found
Prenatal diagnosis of a mosaic supernumerary marker iso (8p) (tetrasomy 8p): discordance between chorionic villi culture and amniotic fluid karyotypes
We describe the first case of mosaic supernumerary marker iso (8p) displaying a karyotype discordance between chorionic villi (CV) and amniotic fluid (AF) cultures during prenatal cytogenetic diagnosis. In the first trimester, cytogenetic analysis after chorionic villi sampling (CVS) was normal in all metaphases in the short-term cytotrophoblast cell culture, but an undefined supernumerary marker was detected in 60% of mesenchymal cells in the long-term CV culture. Informed of the mosaicism, the couple selected amniotic fluid sampling as a second-trimester confirmatory diagnostic procedure. The supernumerary marker was absent in all of the 25 available AF cells metaphases. The prospective parents received genetic counselling and were informed that the discordance could be interpreted as a placental confined mosaicism or as a true foetal mosaicism with low percentage of affected cells. The couple opted to continue the pregnancy. In the second month of life, the child had abnormal development with severe psychomotor delay and frequent episodes of epilepsy. Postnatal cytogenetic extensive re-evaluation discovered that the previously detected supernumerary marker was indeed an isochromosome (8p) rearrangement present at low frequency in 5% of the blood lymphocytes. Copyright (C) 2006 John Wiley & Sons, Ltd
Frequency of the thiopurine S-methyltransferase alleles in the ancient genetic population isolate of Sardinia
Thiopurine S-methyltransferase (TPMT) is an enzyme involved in the normal metabolic inactivation of thiopurine drugs. Patients with intermediate or no TPMT activity are at risk of toxicity after receiving standard doses of thiopurine drugs and it was shown that inter-individual differences in response to these drugs is largely determined by genetic variation at the TPMT locThiopurine S-methyltransferase (TPMT) is an enzyme involved in the normal metabolic inactivation of thiopurine drugs. Patients with intermediate or no TPMT activity are at risk of toxicity after receiving standard doses of thiopurine drugs and it was shown that inter-individual differences in response to these drugs is largely determined by genetic variation at the TPMT locu
Detection of a BAC clone duplication in 17p11.2 in two unrelated patients, affected by severe epileptic encephalopathy, by genome array CGH: a new variant of Potochy-Lupsky syndrome?
The duplication 17p11.2 syndrome, associated with
dup(17)(p11.2p11.2), is a recently recognized syndrome
of multiple congenital anomalies and mental
retardation. It was the first described reciprocal
micro-duplication syndrome that was predicted to
be a reciprocal of a micro-deletion syndrome. It is
the reciprocal of the Smith–Magenis syndrome
caused by a micro-deletion of the same segment
on 17p (Potocky et al. 2007).
We report a novel pathological variant of this
syndrome, detected by genome array-CGH, in two
unrelated subjects with dup(17)(p11.2p11.2),
The array analysis was performed using the BAC
Cyto-chips Blue-Gnome platform, at 0.5-Mb median
resolution, and revealed the presence of the same
BAC duplication in both patients. Fluorescence in situ
hybridization analysis with the same BAC did not
resolve the duplication.
The duplicated BAC (RP11-78O7), of about
140 K, maps in 17p11.2 and contains an interesting
gene, presumably involved in the pathology.
The parents did not show the duplication, suggesting
that it was a de novo rearrangement.
Cytogenetic and clinical features of subjects with
partial trisomy of proximal 17p have been described,
mostly in isolated case reports or literature reviews.
These nonspecific and non-characteristic findings
include developmental delay, mental retardation and
dysmorphic features.
Our patients present a particular form of epileptic
encephalopathy associated with severe mental retardation
and autistic behaviour. Molecular and genetic
studies are in progress to define and characterize the
rearrangement and for better genotype/phenotype
correlatio