XYY syndrome and other Y chromosome polysomies. Mental status and psychosocial functioning.

In this report we review the data on 75 male patients with extra Y chromosome diagnosed in Leuven in the period 1968-1993 among 98,725 patients (males and females) referred for constitutional chromosomal analysis. Special attention was given to their mental performance and psychosocial functioning. 1.

On the excess of mental retardation and/or congenital malformations in apparently balanced reciprocal translocations. A critical review of the Leuven data 1966-1991.

In this report we review 286 reciprocal translocations (rcpt) diagnosed in Leuven in the period 1966, mid 1991. They were selected from a total number of 82,000 patients karyotyped for constitutional reasons. Special attention is paid to: (1) the phenotypic effect of de novo reciprocal chromosomal rearrangements and (2) the incidence of mental retardation/congenital malformations (MR/CM) in familial rcpt.

Turner syndrome: II. Associated anomalies, mental performance and psychological problems in 218 patients diagnosed in Leuven in the period 1965-1989.

Selected medical and psychosocial problems in 218 Turner syndrome patients diagnosed at the Leuven Centre for Human Genetics are reported here. Special attention is paid to the associated congenital malformations, the mental performance and the occurrence of psychosocial and/or characterological difficulties. Mental underdevelopment was documented in 50 patients (22.

Turner syndrome: the Leuven experience (1965-1989) in 478 patients. I. Patient's age at the time of diagnosis in relation to chromosomal findings.

Within the past 25 years 478 patients with Turner syndrome have been diagnosed in the Leuven Centre for Human Genetics. After exclusion of 36 lost pregnancies, mostly first trimester spontaneous abortions, almost 20 per cent of the remaining 442 Turner syndrome patients have been early detected, i.e.

Cytogenetic findings in a consecutive series of 478 patients with Turner syndrome. The Leuven experience 1965-1989.

In this report, we present the cytogenetic findings in 478 patients with Turner syndrome diagnosed in Leuven in the period 1965-1989. The karyotypic anomalies are classified into seven groups: 1) classic, 45,X karyotype (52.1%); 2) mosaic 45,X/46,XX (10.

[Structural chromosomal rearrangements in couples with repeated miscarriages. Experience in Louvain].

In this paper we report our experience in the cytogenetic study of 1555 couples with recurrent first trimester fetal wastage. The frequency of chromosomal anomalies was found to be 6.36%, the majority of then (greater than 50%) being autosomal reciprocal translocations.

Excess of mental retardation and/or congenital malformation in reciprocal translocations in man.

In this report the Leuven experience (1970-1984) on reciprocal translocations is summarized. A total of 153 unrelated index patients, carriers of different types of reciprocal translocations, and their families were investigated. Familial reciprocal, apparently balanced translocations were found in 75 unrelated families bringing the total numbers of translocation carrier parents and their offspring to 132 and 445, respectively.

Inactivation pattern of the fragile X in heterozygous carriers.

Chromosome analysis with conventional staining, G-banding, and R-banding with 5-bromodeoxyuridine (BrdU) incorporation were performed on the lymphocytes of ten females, who were heterozygous for the fragile X-chromosome. Mental development of these females varied greatly: moderate to severe mental retardation was found in one and moderate mental retardation in four females. Normal to borderline intelligence was found in three and normal intelligence was noted in two further females.

Cytogenetic survey in couples with recurrent fetal wastage.

Cytogenetic studies have been performed in 1068 couples with antecedent fetal wastage, i.e., at least two spontaneous first trimester abortions or one spontaneous first trimester abortion and one late fetal death, particularly with multiple congenital malformations.

Cytogenetic findings in moderate and severe mental retardation. A study of an institutionalized population of 1991 patients.

The cytogenetic data of a large scale study in an institutionalized population of 1991 moderately and severely mentally retarded patients are presented. In 21.3% of these patients a chromosomal aberration was diagnosed (14.

Ring chromosome 14. A distinct clinical entity.

In this report two non consanguineous children are presented with strikingly similar phenotypes confirming the existence of a characteristic phenotype due to a ring chromosome 14 formation.

XY/XXY mosaicism and fragile X syndrome.

Clinical and cytogenetic data of a XY/XXY mosaic Klinefelter patient with fragile X are presented.

Familial translocation t(lp--;21q+) associated with Down's syndrome.

Familial occurrence of 1/21 translocation in connection with trisomy 21 was described. The possibilities of inheritance of further chromosome rearrangements arising during the gametogenesis of persons with this translocation were considered.

Familial occurrence of chromosome variant 17ph+.

A structural chromosome variant 17ph+ was found in a high genetic risk family. The authors consider the possibility of a causal connection between minor structural changes in the karyotype and congenital defects appearing in one member of the family.