Search

Background: Chromosomal anomalies are a recognized cause of stillbirth, accounting for 6–17% of the cases. As a diagnostic laboratory method in this setting, conventional karyotyping has two main drawbacks: the need for viable fetal cells in a dead fetus and its limited resolution as compared to alternative techniques. Objective: To assess the effectiveness of cytogenetic analysis in stillbirths between different testing methods and different sampled tissues. Methods: From 2011 to 2017, 145 stillborn fetuses (defined as fetal losses after 22 weeks) were delivered in our center. The stillbirth protocol includes genetic testing by means of a karyotype, QF-PCR, or chromosomal microarray analysis (CMA), depending on the presence of fetal structural anomalies and the study time period. The success rates were compared between tests and between different sampled tissues. Results: Consent was granted for cytogenetic analysis in 136 stillbirths. Test success rate was 100% (38/38) for CMA independent of the sampled tissue, 99% (65/66) for QF-PCR, and 66% (65/98) for karyotyping. The success rate for karyotyping was 48% (69/145) of the total tissues samples, showing great variation according to the tissue sampled: 83% (40/48) in amniotic fluid, 78% (21/27) in the placenta, 13% (7/54) in fetal skin, and 6.3% (1/16) in fetal blood. Four full or partial aneuploidies (trisomy 9, trisomy 22, tetrasomy 18p, and monosomy X) and 2 microdeletions (del2p16.3 and del1q13.2q13.4) were found, resulting in a 3.9% (4/103) prevalence for full or partial aneuploidy and a 5.3% prevalence (2/38) for submicroscopic abnormalities. Conclusions: Amniotic fluid should be the preferred tissue source in the cytogenetic analysis of stillbirth due to its high success rate. Between tests, CMA is a preferable method because of its higher test success rate, independent of the sampled tissue, and higher diagnostic yield including chromosomal and submicroscopic anomalies.

Trisomy 22 is a common trisomy in spontaneous abortions. In contrast, live-born trisomy 22 is rarely seen due to severe organ malformations associated with this condition. Here, we report on a male infant with complete, non-mosaic trisomy 22 born at 35 + 5 weeks via caesarean section. Peripheral blood lymphocytes and fibroblasts showed an additional chromosome 22 in all metaphases analyzed (47,XY,+22). In addition, array CGH confirmed complete trisomy 22. The patient’s clinical features included dolichocephalus, hypertelorism, flattened nasal bridge, dysplastic ears with preauricular sinuses and tags, medial cleft palate, anal atresia, and coronary hypospadias with scrotum bipartitum. Essential treatment was implemented in close coordination with the parents. The child died 29 days after birth due to respiratory insufficiency and deterioration of renal function. Our patient’s history complements other reports illustrating that children with complete trisomy 22 may survive until birth and beyond.

The inversion of chromosome 16 (inv(16) (p13q22)) and the related t(16;16)(p13;q22) are chromosomal aberrations observed in approximately 10% of de novo acute myeloid leukemia (AML), mostly classified as M4Eo subtype, and associated with a relatively favorable outcome. However, it is a cryptic rearrangement and often difficult to recognize in conventional cytogenetics (CC). Trisomy 22 is an uncommon karyotypic aberration in AML and is often associated with inv(16)(p13q22). The aim of this study was to explore the value of trisomy 22 in the diagnosis of AML with inv(16).Dual-color interphase fluorescence in situ hybridization (FISH) was performed in 19 AML cases with trisomy 22 abnormality shown by R-banding CC. The probe was a two-color break-apart probe for CBFbeta on the centromeric side and the telomeric side.R-banding CC did not reveal inv(16) in any of the 19 AML with trisomy 22, but FISH analysis showed inv(16) in 11 cases and del(16)(q22) in 1 case. Among the 11 cases with inv(16), 9 showed trisomy 22 as the sole abnormality, 1 was complicated by trisomy 8, and 1 was del(16)(q22).This study further confirmed that trisomy 22 as the sole abnormality can be regarded as an important marker for inv(16) in AML.

A behaviorally and clinically abnormal female orangutan was analyzed cytologically using general banding techniques and by an alkaline silver method for staining nucleolus organizer regions. The karyotype had 49 chromosomes, including an extra chromosome 22 (49, XX, + 22). No variant chromosome types or heterozygous structural rearrangements were found. Nine of the 14 large acrocentric chromosomes, Nos. 11–17, and three of the five presumptive human G-group equivalents, i.e., two of three chromosomes 22, and one chromosome from pair 23, exhibited positive silver staining of the nucleolus organizer region (NOR).

Orangutan metaphase chromosomes, obtained from a female animal with trisomy 22, were stained by a recently developed distamycin/DAPI fluorescent technique which had been shown to differentiate specific C-bands on human chromosomes, as well as by other banding techniques. Distamycin/DAPI-brilliant fluorescence was observed in the short arm regions of acrocentric chromosomes 11–17, 22 and 23, and a brightly fluorescent paracentromeric band was seen on chromosome 8. A smaller amount of fluorescence was found adjacent to the centromere of most of the other chromosomes. Sequential distamycin/DAPI and Giemsa C-staining of the same metaphases revealed that the “hot-spots” on acrocentrics correspond to C-band material in their short arm. The less intensely fluorescent centric bands on other chromosomes coincide with centromeric C-bands. Reverse fluorescent staining of orangutan chromosomes with chromomycin A3 revealed brightly fluorescent regions at short arms of some acrocentrics probably confined to the satellite, either in a heteromorphic form (Nos. 11, 14, 17) or of similar size (No. 22).

Karyotyping of eight malformed calves resulted in the detection of trisomy 22 in one calf. This calf had a hernia umbilicalis, a urachus fistula, and slight brachygnathia inferior. This trisomy was not associated with lethality.