Incontinentia pigmenti (type 1) and X;5 translocation.

The authors present a 5-year-old girl with total absence of speech, dysmorphic features, pigmented lesions on the legs, an abnormal EEG and otherwise normal intelligence representing a mild form of type 1 Incontinentia pigmenti associated with an (X;5) (p11.2;q35.2) apparently balanced translocation prenatally diagnosed. The seven previous translocation type 1 IP patients are reviewed and all have the same Xp11 breakpoint. Somatic cell hybrids have been made to further study this breakpoint and further define the putative type 1 IP gene.

Chromosome abnormalities detected in chorionic villus biopsies of failing pregnancies in a subfertile population.

OBJECTIVE: To determine the range and prevalence of chromosomal abnormalities occurring in failing pregnancies in subfertile women. DESIGN: Prospective biochemical and ultrasound monitoring of all pregnancies conceived between 1988 and 1990 in a subfertile population. SETTING: A single-centre specialist fertility clinic in Perth, Western Australia. SUBJECTS: Tissue from 50 early pregnancy losses was successfully cultured for chromosomal analysis from 46 pregnancies comprising 29 anembryonic pregnancies, 9 miscarriages and 8 ectopic pregnancies. MAIN OUTCOME MEASURES: Impending pregnancy loss was identified at an early stage. Chromosomal analysis was performed on chorionic villi obtained before the diagnosis became clinically evident. RESULTS: Significant chromosomal abnormalities were identified in 54% (14/26) of early pregnancy losses where gamete manipulation was involved and 45% (9/20) of those following spontaneous conception. The most common abnormalities were trisomies (12 pregnancies, mainly trisomy 16), triploidies (3 pregnancies) and monosomy X (3 pregnancies). An excess of female fetuses was noted with only 24% of conceptuses (11/46) bearing a Y chromosome. CONCLUSIONS: The data indicate a similar rate of chromosomal abnormalities underlying pregnancy losses at earlier stages of pregnancy and after infertility treatments as that reported from the general population. Gamete manipulation does not appear to confer a higher rate of chromosomal abnormalities in ensuing pregnancies.

Tyrosinase positive albinism with familial 46,XY,t(2;4) (q31.2;q31.22) balanced translocation.

A subject with clinical and biochemical tyrosinase positive oculocutaneous albinism (OCA) also had a balanced translocation, 46,XY,t(2;4)(q31.2;q31.22). This observation provides evidence for a possible gene locus in the q31 region of chromosome 2 or 4.

Intrathoracic carcinoma in an 11-year-old girl showing a translocation t(15;19).

We report here a rare case of intrathoracic undifferentiated carcinoma in an 11-year-old girl. The biopsy tissue stained with antibodies against cytokeratin and carcino-embryonic antigen. The same staining was obtained using a cell line, PER-403, which was derived from the tumor. DNA from PER-403 cells was tested for the presence of Epstein-Barr virus genes, yielding a negative result. The cytogenetic analysis found a translocation t(15;19) (p12;q13), which has not previously been described in a carcinoma.

Campomelic dysplasia with sex reversal: morphological and cytogenetic studies of a case.

Morphological and cytogenetic studies undertaken in a case of sex reversed campomelic dysplasia revealed the presence of primary follicles within the dysgenetic gonads and a familial balanced chromosome translocation t(5;8), a hitherto unreported combination of unusual findings.

Fetal abnormality (Goldenhar syndrome) occurring in one of triplet infants derived from in vitro fertilization with possible monozygotic twinning.

Of 36 infants delivered following conception by in vitro fertilization (IVF), 1 case of significant fetal abnormality has been detected. The infant is one of male triplets exposed to medroxyprogesterone acetate (MPA) in utero and demonstrates abnormalities of the ear, vertebral column, and ribs which fit clearly into the oculoauriculovertebral syndrome described by Goldenhar and which have been reported in monozygotic twins with discordance. Marker studies including eight blood groups, HLA haplotype assignments, and banding studies of the chromosomes indicate that the infant and one of his brothers may well be identical (P less than 0.001 for dizygosity) except for the Fy(a) antigen. It is deduced that the fetal abnormality is not causally related either to MPA exposure or to the techniques applied during fertilization and early embryo culture, and furthermore, if the infant is the monozygotic twin of one of his brothers, the two phenomena are unrelated, as each was likely to have occurred at different stages of embryonic development.

Monozygotic twins from in vitro fertilization.

A case of identical twins following in vitro fertilization and embryo transfer ( IVF -ET) is described. Two embryos were transferred, but it is apparent that only one implanted and subsequently divided in the early implantation phase to produce identical male twins within a monochorionic , diamniotic placental and membrane configuration. Additional marker studies provide an overall probability of less than 0.001 for dizygosity . There is unlikely to be any relationship between this event and the technique of IVF -ET.

The effect of prenatal diagnosis on the incidence of Down syndrome in Western Australia.

This paper compares the incidence rates of Down syndrome livebirths in Western Australia during two 5-year periods before and after the advent of prenatal cytogenetic diagnosis. A statistically significant fall in the incidence of liveborn Down syndrome is demonstrated and the relevance of amniocentesis screening is discussed in the light of possible future demographic change.

Prenatal diagnosis of a double heterozygote for two reciprocal translocations of familial origin.

Two balanced reciprocal translocations were found in an amniotic fluid cell culture undertaken because of maternal age. One translocation had been inherited from each parent. Both translocations were traced through three generations of each family. The importance of banding techniques in diagnostic cytogenetics is stressed.

The utilization of prenatal cytogenetic diagnosis in Western Australia.

Prenatal cytogenetic diagnostic services for the whole of Western Australia are undertaken by 1 central department in Perth. The records of this unit have been used to calculate the utilization rates of amniocentesis by women aged 35 years or older at the estimated date of confinement for the 5-year period 1977-1981. During this time there were 5076 livebirths to mothers aged 35 years or more and 1,408 pregnancies in this age group were cytogenetically monitored, giving an overall utilization rate of 28%. This rate is comparable to similar rates in other developed countries. Possible directions for future expansion of the service are suggested.

Cytogenetic studies in recurrent fetal loss.

The results of cytogenetic studies of 19 couples with a history of a malformed stillbirth plus 1 or more early spontaneous abortions were compared with those of 66 couples with a history of 2 or more early spontaneous abortions and a control group of 583 couples with no history of fetal loss. The incidence of structural chromosome abnormality was highest in the first group and there was no significant difference between groups in the incidence of polymorphisms of the 9 and Y chromosomes.