European recommendations and quality assurance for cytogenomic analysis of haematological neoplasms

Cytogenomic investigations of haematological neoplasms, including chromosome banding analysis, fluorescence in situ hybridisation (FISH) and microarray analyses have become increasingly important in the clinical management of patients with haematological neoplasms. The widespread implementation of these techniques in genetic diagnostics has highlighted the need for guidance on the essential criteria to follow when providing cytogenomic testing, regardless of choice of methodology. These recommendations provide an updated, practical and easily available document that will assist laboratories in the choice of testing and methodology enabling them to operate within acceptable standards and maintain a quality service.

Cytogenetic Nomenclature: Changes in the ISCN 2013 Compared to the 2009 Edition

The latest edition of the International System for Human Cytogenetic Nomenclature, ISCN 2013, has recently been published following a thorough revision of the 2009 issue and the incorporation of suggestions from the community by the current standing committee. This review will highlight the multiple nomenclature changes in the respective chapters of the 2013 version compared to the previous version of the ISCN published in 2009. These highlights are meant as a guide for the cytogeneticist to assist in the transition in the use of this updated nomenclature for describing cytogenetic and molecular cytogenetic findings in both clinical and research reports.

Aneuploidy screening in direct chorionic villus samples by fluorescence in situ hybridisation: the use of commercial probes in a clinical setting

The results of screening for the common aneuploidies involving chromosomes 13, 18, 21, X and Y by florescent in-situ hybridisation (FISH) in direct preparations from 100 chorionic villus samples from pregnancies between 10 and 20 weeks' gestation are reported. Samples prepared using routine methods and analysed with commercially available probes, accurately detected 12 cases of fetal aneuploidy, all referred because of developmental abnormality. Three of the four cases where chromosome abnormality was detected in cultured villi but not by the direct fluorescence in situ hybridisation (FISH) assay, were due to confined placental mosaicism. No chromosomal anomalies were found in the 20 low risk cases where the referral reason was a familial single gene disorder. We conclude that the FISH assay with commercial probes may act as an accurate and less labour intensive alternative to direct chromosome analysis of chorionic villus samples. In cytogenetically low risk cases its use can obtain a result within the time needed for DNA analysis and avoid the need to set up cultures.

Non-syndromic mental retardation segregating with an apparently balanced t(1;17) reciprocal translocation through three generations

We describe a family in which non-syndromic mental retardation (MR) and an apparently balanced reciprocal translocation, t(1;17)(p36. 3;p11.2) segregates in eight individuals over three generations. Four children showed psychomotor developmental delay, reduced muscle tone, poor coordination, and learning difficulties. The affected adults had a varying range of behavioral problems and difficulties in social adjustment but no abnormal neurological signs. Most of them were functioning at the borderline learning difficulty level in intellectual abilities with additional specific difficulties in reading in two individuals. The Smith-Magenis and 1p36.3 deletion syndromes were excluded. We propose that this reciprocal translocation has disrupted an autosomal gene with an important function in cognitive development, and this family represents a unique resource for the molecular genetic study on non-syndromic MR.

Prenatal detection of extra structurally abnormal chromosomes (ESACs): new cases and a review of the literature

We present 16 cases, 10 de novo and 6 familial, in which extra structurally abnormal chromosomes (ESACs) were diagnosed prenatally and identified by fluorescence in situ hybridization (FISH) studies with follow up from birth. We review the literature on prenatally diagnosed ESACs arising de novo and suggest a management protocol for these cases.

Prenatal finding of a fetus with mosaicism for two balanced de novo chromosome rearrangements

Karyotyping of a fetus with mild cerebral ventriculomegaly detected with ultrasound at 23 weeks revealed two apparently balanced structural rearrangements in mosaic form. Using conventional cytogenetics and FISH, the chromosomal constitution was identified as 46,XX,t(3;10)(p13;q21.1),inv(6)(p23q12)/46,XX. A 46,XX chromosome constitution was predominantly present in the skin whereas in the fetal blood the cell line with two balanced chromosome rearrangements was selectively retained. To the best of our knowledge this is the first prenatal case of mosaicism for two de novo balanced structural chromosome rearrangements to be reported.

Cellular heterogeneity in a tissue culture cell line derived from a human bladder carcinoma

To study heterogeneity in a cell line derived from a human bladder carcinoma (EJ), 7 clones were isolated at low passage and examined for differences in culture behaviour, ability to grow in agar and tumorigenicity in nude mice. The parent EJ line had several distinct chromosome populations (both diploid and tetraploid), grew in agar and produced tumours in nude mice. Three of the clones had pseudodiploid modes and 4 had either hypo- or hypertetraploid modes. The 7 clones had 5 marker chromosomes in common but the combination of other marker chromosomes made each clone unique. No significant difference was found between the clones in the in vitro growth rate although analysis of in vitro culture behaviour showed heterogeneity in the pattern of cell movement on plastic substratum. Three clones were composed of static cells, one clone had very mobile cells; the other clones had rates of movement intermediate between the two. Differences were also found in the packing density of the cloned cells and in the cell size. All 7 clones grew in agar but heterogeneity was seen between the clones as shown by widely varying colony-forming efficiencies (0.5-13%). One clone had a high colony-forming ability in agar but failed to produce tumours in nude mice. The other clones were tumorigenic regardless of colony-forming efficiency in agar. Specific chromosome abnormalities were found to be associated with growth in agar and tumorigenicity but not with the growth pattern or the rate of movement of the cloned cells in culture.

Chromosome pattern, growth in agar and tumorigenicity in nude mice of four human bladder carcinoma cell lines

Four human bladder carcinoma cell lines have been characterized by G-banding, and the chromosomal patterns correlated to growth in agar and tumorigenicity in nude mice. Each cell line was shown to be chromosomally unique and although numerical and structural anomalies were present, none were common to all four cell lines. However, one or more copies of a structurally altered chromosome 8 were present in all four cell lines and may be associated with tumorigenicity in nude mice. A combination of three marker chromosomes was found in the more anaplastic cell lines, but not in the two well-differentiated tumour cell lines. Growth in agar may be associated with the presence of the three marker chromosomes but was not correlated with tumorigenicity in nude mice.

A STUDY OF THE PATHOGENICITY OF THE MEADOW NEMATODE AND ASSOCIATED FUNGUS CYLINDROCARPON RADICICOLA WR

The meadow nematode Pratylenchus pratensis has been isolated from root lesions of narcissus, strawberry, apple, cherry, and raspberry in British Columbia. When apparently freed from associated fungi, this species reduced the growth of potato, carrot, red clover, tomato, spinach, and violet seedlings by 50 to 75%, and oat seedlings by less than 4%. In parallel experiments, the commonly associated fungus Cylindrocarpon radicicola as a pure culture reduced growth by only 6 to 11%. The inhibition of growth by the fungus and nematode as a mixed culture was usually greater than the sum of the reductions as pure cultures.The nematodes were separated from associated fungi by planting segments of infested oat roots in plate cultures of powdered peat moistened with a 0.1% solution of malachite green. When the oats planted in this medium had germinated, the nematodes moved from the root segments through the fungicidal medium into the roots of the oat seedlings. These nematode-infested roots proved to be free from the fungi and bacteria naturally associated with the nematode in field infestations.The adult and all the larval stages of P. pratensis proved to be capable of entering the roots of oat seedlings.

THE TREATMENT OF GLASSHOUSE SOILS WITH CHLOROPICRIN FOR THE CONTROL OF HETERODERA MARIONI (CORNU) GOODEY, AND OTHER SOIL PATHOGENS

Chloropicrin in 1 cc. doses is lethal to bulb nematodes at six inches from the point of injection or within a soil volume of one cubic foot. It is also lethal to fungi. The vegetative stages are destroyed at 1:195,000, and certain sclerotia at 1:90,000.The injection of chloropicrin into greenhouse soils lowered the incidence and pathogenicity of a root-knot infection on both a summer and winter crop of tomatoes and greatly increased the yields of fruit. The chloropicrin costs $1.65 per pound or $8.50 to treat 2000 sq. ft. of soil.

THE EFFECT OF TEMPERATURE UPON THE PRE-ADULT LARVAE OF THE BULB NEMATODE ANGUILLULINA DIPSACI (KÜHN, 1858) GERV. AND v. BEN., 1859, IN RELATION TO TIME AND MOISTURE

In a moist environment, a minimum exposure of 120 min. at 110–113°F. is required to destroy pre-adult larvae of the bulb nematode Anguillulina dipsaci (Kühn, 1858) Gerv. and v. Ben., 1859, but progressively shorter exposures are required as the temperature is raised. At 116.5–118.5°F. the lethal exposure is 60 min. and at 118.5–120°F. an exposure of 30 min. is required.In a dry environment exposures of 150 min. to temperatures as high as 140°F. are not lethal to pre-adults and the heat treatment does not affect their ability to induce the characteristic symptoms of infestation in barley seedlings.The pre-adults are more resistant to heat than any other stage in the life history of the nematode.The data suggest that the ineffectiveness of the standard hot water treatment when applied late in the season is due to the fact that the major development of pre-adults takes place after the bulbs are lifted, and also because the masses of dormant pre-adults are often well isolated from the moisture of the bath by the bulb scales and corky basal plates, and are more resistant to heat in a dry, compared with a moist, state. It is recommended that the hot water treatment be employed not later than four weeks after lifting when the lifting is done as soon as the foliage dies down.A pre-soak is suggested as a possible means of increasing the effectiveness of the standard hot water treatment.