Helga Muller

Identification of 21 r and 22r chromosomes by quinacrine fluorescence

Quinacrine fluorescence has been used to identify ring G chromosomes as a 21 r in one patient and a 22r in two patients. Our finClings confirm the association of ‘antimongolism’ with a 21r, but apart from profound mental retardation, the 22r appears to produce only minimal physical changes.

The frequency of trisomy and translocation in Down's syndrome

Data are now available to provide guidelines for determining which patients with Downs syndrome, and their families, should be studied by chromosomal analysis to determine if the disorder is genetically transmitted. Tables are presented to indicate the approximate incidence or frequency of the trisomy and translocation syndromes at different maternal ages, as well as the probability of a transmittable translocation. Available data indicate that if the maternal age is less than 30 years at the time of the birth of an infant with Downs syndrome, there is a 1 in 50 probability that the affected child has an inherited translocation; if the maternal age is 30 years or over, the chances are about 1 in 333. These estimates do not refer to recurrence risks, but rather to probabilities of an inherited translocation associated with Downs syndrome.

Ring 10 chromosome: 46,XX,r10(p15q26)

SummaryA teenage girl with mild retardation and some clinical features suggestive of the Turner syndrome was found to have an r10(p15q26) in blood and skin cells. Quantitative evaluation of 28 red cell enzymes, including two (hexokinase and glutamic-oxaloacetic transaminase) known to be on chromosome 10, gave normal values.

Ring 11 chromosome (46,XX,r11(p15q25))

SummaryA girl has a stable ring chromosome 11, which does not reveal loss of any chromosomal material. She demonstrates small stature, mild retardation, behavior problems, mild abnormal EEG, prominent sole furrows, increased deep tendon reflexes and hypothyroidism; this latter condition may have contributed to her retardation.

Insertional translocation into the X chromosome of a 46, XY male

A baby boy with multiple congenital anomalies and low birth weight has an apparent de novo insertional translocation into the long arm of his only X chromosome. The origin of the translocated material is not evident and both cytogenetic and X‐linked marker studies do not indicate any loss of genetic material from the X chromosome. His findings are compared with other males who have X‐translocations, none of which appear to be insertional translocations.

Clinical and cytogenetic variations of gonadal dysgenesis in 3 patients

Abstract The clinical and cytogenetic heterogeneity of gonadal dysgenesis is illustrated by three patients who have a partially deleted X chromosome in some or all of their cells. Their variable findings emphasize the need for extensive evaluations in patients with gonadal dysgenesis to accurately define the syndrome in each patient. Comparisons with similar patients from the literature are made. Chromosome-phenotype correlations and special problems of sex chromosome abnormalities are discussed.

Double monosomy mosaicism (45,X/45,XX,21–) in a retarded child with multiple congenital malformations

Double monosomy mosaicism was observed in a three-year-old girl who had mental and physical retardation. Routine blood-lymphocyte and bone-marrow chromosome studies showed an apparent 45, X pattern, w

Ring 13 or ring 14: distinction by banding analysis of a culture derived from tissue frozen for 10 years

Several years ago, before banding analysis was available, we described a patient with a ring D chromosome which appeared to be a r(14) by autoradiography with tritiated thymidine (Sparkes et al., 1967). The patient died shortly after our report. Skin fibroblasts had been stored in liquid nitrogen but several recent attempts to carry out banding chromosome analyses on these were unsuccessful. Specimens of testes obtained at autopsy were stored in liquid nitrogen (Kihara et al., 1975). The testes were prepared by washing with a buffer-antibiotic solution and by mincing to explant size. These small pieces of tissue (10 pieces in 1 ml/ampule) were added to the following freezing solution: medium 199 with Earles salts (Gibco E-11), 0.1 g glutamine, 2.2 g NaHCO3, 10 000 units penicillin, 10rag streptomycin, 10ml calf serum, 5ml fetal calf serum, made to 100ml, pH 7.4; 10 ml of DMSO were added to 90 ml of this medium to make the freezing solution. The ampules were sealed, cooled at the rate of 1--2 ° C/min to -40 ° C and then placed in liquid nitrogen. Approximately 10 years later the tissues were recovered by placing the ampules in a 37°C water bath for rapid thawing and were explanted in plastic T-flasks to which were added 5ml of the following medium: MEM with Earles salts (Gibco F-11), 0.1 g glutamine, 2.2g NaHCO3, 5.96 g HEPES, 50 mg Aureomycin, 5000 units Mycostatin, 15 ml fetal calf serum made to 100 ml, pH 7.4. The flasks were incubated at 37 ° C with tight caps and the media changed twice weekly. Outgrowths were first noted after 10 days of culture and were ready for subculture 2 weeks later. Trypsin-Giemsa chromosome banding analysis was made from a subculture and showed 13 cells with a ring (13) chromosome (Fig. 1) while 6 cells lacked the ring chromosome and contained one normal 13 chromosome; a similar porportion of cells had been noted earlier from a fibroblast culture (Sparkes et al., 1967). The size of the ring appears to be relatively constant and contains about half the usual amount of chromosome 13 material. The banding pattern .of the ring chromosome is not sufficiently clear to identify which specific parts of the chromosome have been lost in the ring formation, although the results are compatible with this lost material being derived largely from the distal 13q.