Fertility in patients with X chromosome deletions

A Rare Variant of Turner Syndrome in Four Sequential Generations: Effect of the Interplay of Growth Hormone Treatment and Estrogens on Body Proportion

BACKGROUND

Terminal Xp deletion leads to SHOX haploinsufficiency, and when it exceeds Xp22.33 it causes a variant of Turner syndrome (TS) in which gonadal function is preserved and short stature constitutes the major clinical feature.

CASE REPORT

We present a family with vertical transmission of TS that affected six women in four sequential generations. The karyotype was defined as a combination of terminal Xp deletion and terminal Xq duplication: 46,X,rec(X)inv(p21.1q27.3). All affected women had short stature, but had developed spontaneous puberty and normal fertility. Generation IV exclusively received recombinant human growth hormone (rhGH). We investigated the effect of rhGH treatment on skeletal growth and body proportion via the comparison of auxological data from an untreated 39.7-year-old mother to her 14.8-year-old rhGH-treated daughter. The adult height of the daughter was substantially better than that of the mother [160.3 cm (-0.8 SDS) and 150.0 cm (-2.7 SDS), respectively]; however, the disproportion progressed following rhGH treatment and ultimately led to a worse trunk-to-extremities ratio compared with the mother (4.8 and 3.7 SDS, respectively).

CONCLUSION

This rare family confirms the vertical transmission of TS spanning multiple generations. The combination of endogenous estrogen production and exogenous rhGH administration in women with SHOX haploinsufficiency may worsen their body disproportion.

De novo isodicentric X chromosome: 46,X,idic(X)(q24), and summary of literature

We describe a 12-year-old patient, the second live born prenatally ascertained patient in the literature, with a de novo isodicentric X chromosome, karyotype 46,X,idic(X)(q24), with normal growth and development and lack of dysmorphic features. Molecular and cytogenetic studies were performed to further characterize the isodicentric chromosome X behavior. Literature on isodicentric X chromosomes with various breakpoints on Xq is reviewed and summarized.

Short stature in a mother and daughter caused by familial der(X)t(X;X)(p22.1-3;q26)

Deletions of the terminal Xp regions, including the short-stature homeobox (SHOX) gene, were described in families with hereditary Turner syndrome and Léri-Weill syndrome. We report on a 10-2/12-year-old girl and her 37-year-old mother with short stature and no other phenotypic symptoms. In the daugther, additional chromosome material was detected in the pseudoautosomal region of one X chromosome (46,X,add(Xp.22.3)) by chromosome banding analysis. The elongation of the X chromosome consisted of Giemsa dark and bright bands with a length one-fifth of the size of Xp. The karyotype of the mother demonstrated chromosome mosaicism with three cell lines (46,X,add(X)(p22.3) [89]; 45,X [8]; and 47,X,add(X)(p22.3), add(X)(p22.3) [2]). In both daughter and mother, fluorescence in situ hybridization (FISH), together with data from G banding, identified the breakpoints in Xp22.1-3 and Xq26, resulting in a partial trisomy of the terminal region of Xq (Xq26-qter) and a monosomy of the pseudoautosomal region (Xp22.3) with the SHOX gene and the proximal region Xp22.1-3, including the steroidsulfatase gene (STS) and the Kallmann syndrome region. The derivative X chromosome was defined as ish.der(X)t(X;X)(p22.1-3;q26)(yWXD2540-, F20cos-, STS-, 60C10-, 959D10-, 2771+, cos9++). In daughter and mother, the monosomy of region Xp22.1-3 is compatible with fertility and does not cause any other somatic stigmata of the Turner syndrome or Léri-Weill syndrome, except for short stature due to monosomy of the SHOX gene.

Structural chromosome rearrangements in couples with recurrent fetal wastage

OBJECTIVE

A review of the cytogenetic data in 1743 couples (3486 patients) with recurrent fetal wastage (RFW) who were examined for RFW at the Leuven Centre for Human Genetics in the period 1986-1995. These results were compared with a previous study in the period 1970-1985.

SUBJECTS

Patients who had at least two first trimester miscarriages or patients who had a spontaneous first trimester abortion, preceded or followed by a second or third trimester fetal death.

RESULTS

Chromosomal rearrangements were found in 5.34%. Two-thirds of these chromosomal rearrangements were autosomal balanced translocations. This finding is a 30-fold increase compared to the general population. Other chromosomal abnormalities included Robertsonian translocations, inversions and sex-chromosomal abnormalities.

DISCUSSION

The Leuven experience was compared with several other studies. Mechanisms causing these chromosomal abnormalities are presented.

CONCLUSIONS

Chromosomal analyses are an important and necessary part of the etiological investigations in couples with RFW.

Del (X)(p21.2) in a mother and two daughters with variable ovarian function

We report a family in which a woman with the mosaic karyotype 45,X/46,X,del(X)(p21.2) transmitted the deleted X chromosome to two daughters. The nature of the deletion was confirmed by fluorescent in situ hybridization (FISH). All three family members showed somatic Ullrich-Turner syndrome features, but only one daughter had ovarian failure. These observations have implications for the diagnosis of Ullrich-Turner syndrome and genotype/phenotype correlations of X chromosome deletions.

Turner syndrome in a mother and daughter: r(X) and fertility

A patient with mosaic Turner syndrome and normal fertility had three documented pregnancies. She had a 45,X/46,X,r(X) karyotype and did not undergo spontaneous sexual maturation and menarche. Conception occurred while on hormone replacement therapy. Her first pregnancy ended with the birth of a normal 46,XY male, while the third pregnancy resulted in a healthy 45,X/46,X,r(X) female. A review of the literature reveals a myriad of theories to account for the variability of ovarian function in Turner syndrome, but, as yet, there are insufficient data to yield any conclusions. There appears to be an increased risk of trisomy 21 in the offspring of females with Turner syndrome.

Familial transmission of a duplication-deficiency X chromosome associated with partial Turner syndrome

A rearranged X chromosome Xqter-->q13::Xp11.4-->qter was found in a mother and her two daughters, who were affected with short stature, cubitus valgus and hypothyroidism. The mother's menstrual cycles were normal until the age of premenopause. Similar previously reported cases are considered in an attempt to explain the possible origin of this X recombinant, fertility and clinical traits.

Mild phenotype and normal gonadal function in females with 4p trisomy due to unbalanced t(X;4)(p22.1;p14)

In this report we describe the mild phenotypic manifestations and normal gonadal function in a 50-year-old mother and her 17-year-old daughter with 4p trisomy resulting from an unbalanced t(X;4)(p22.1;p14) mat. Late replication of the der(X) was demonstrated by BrdU incorporation with spreading of the late replication to the 4p portion as an explanation of the reduced effect of the trisomy 4p/monosomy Xp on the physical and secondary sexual development in both patients.

Deletions of Xq and growth deficit: a review

A critical review of the literature disclosed 44 cases with a 46,X,Xq- karyotype without apparent mosaicism. Of these, 17 were of normal height (compared to the respective population), 11 had a height of over 1 SD below the mean, and 16 had a height of over 2 SD below the mean with breakpoints between Xq13 and Xq25. Since patients of normal height occurred with breakpoints as proximal as Xq13 we conclude that there is no major "growth gene" on Xq distal to q13. The most likely explanation for the variable phenotypic effect of Xq- is to assume that growth gene(s) in Xp or proximal Xq are inactivated on such a chromosome with some variability similar to the variable spreading of X inactivation seen in some X-autosome translocations.

Deletion of the short arm of the X chromosome: a hereditary form of Turner syndrome

In the mothers of two girls with Turner syndrome due to a deletion of the short arm of an X chromosome, the same chromosomal anomaly was detected. Both mothers and daughters had short stature but normal pubertal development. Short parents and normal pubertal development do not exclude Turner syndrome in a girl with small stature.

Familial Turner syndrome

A 28-year-old Turner female with secondary amenorrhea is described, who showed 45,X/46,X,del(Xp) mosaicism in her blood lymphocytes and a 46,X,del(Xp) karyotype only in her ovaries. 45,X/46,XX mosaicism was found in the patient's mother, who presented short stature, mild Turner dysmorphism and had a normal reproductive life-span. Phenotypic implications of the cytogenetic findings in the patients are discussed, and literature data on fertility in Turner syndrome are briefly reviewed.

Turner syndrome and its variants

Turner syndrome is suspected in females with short stature, gonadal dysgenesis, and lymphedema; however, there are no pathognomonic features of Turner syndrome, and the disorder should be considered in any girl with short stature or delayed puberty. This article discusses the natural history of Turner syndrome and complications that occur in various organ systems; it reviews the physical features and complications seen with various karyotypic changes in Turner syndrome. Age-specific screening and therapies are covered.

Distal long arm deletions of the X chromosome and ovarian failure

A mother and daughter are described with premature menopause and deletion of the X chromosome at q28.

Chromosome studies and fertility treatment in women with ovarian failure

In vitro fertilization and embryo transfer or gamete (or zygote) intra-Fallopian transfer after ovum donation were performed in 16 patients with primary or secondary amenorrhea, associated with chromosome abnormalities. The patients showed the wide range of (mostly X) chromosome abnormalities characteristic for women with primary or premature ovarian failure. Four of these patients became pregnant and three of them have delivered healthy infants with a normal karyotype. This pregnancy rate is far superior to the accepted fertility figure in these patients. When these results were compared with the fertility treatment results of three other groups of women with absent ovarian function (1. ovarian dysgenesis; 2. surgical castration; 3. premature menopause) but with a normal 46,XX karyotype, no difference in treatment efficiency could be detected. These results offer a promising approach for the treatment of infertility in agonadal patients with chromosome aberrations.

Fertility and X-chromosome rearrangements: isodicentric X-chromosome formation in the mother and Xp deletion in her daughter

In the present paper we report the first example of fertility in a female with isodicentric X-formation and karyotype 45,X/46,X,del(X)(pter----p21.3)/46,X,idic(X)(qter----p21.3::p21.3- ---qter). Her daughter was phenotypically almost normal and presented a 46,X,del(X)(pter----p21.3) karyotype in all examined cells.

Fertility with deletion Xq25: report of three cases; possible exceptions for critical region hypothesis

We report on an Arab family in which a mother and two of her daughters, despite having deletion Xq25, are fertile. So far, only one case of deletion Xq25 associated with fertility has been reported. Consistent inactivation of the deleted X chromosome in the proposita and early menopause in the mother were noted. The effect of Xq deletion on fertility and the CRH is discussed.

Complete cloning of the Duchenne muscular dystrophy (DMD) cDNA and preliminary genomic organization of the DMD gene in normal and affected individuals

The 14 kb human Duchenne muscular dystrophy (DMD) cDNA corresponding to a complete representation of the fetal skeletal muscle transcript has been cloned. The DMD transcript is formed by at least 60 exons which have been mapped relative to various reference points within Xp21. The first half of the DMD transcript is formed by a minimum of 33 exons spanning nearly 1000 kb, and the remaining portion has at least 27 exons that may spread over a similar distance. The DNA isolated from 104 DMD boys was tested with the cDNA for detection of deletions and 53 patients exhibit deletion mutations. The majority of deletions are concentrated in a single genomic segment corresponding to only 2 kb of the transcript.

Non-mosaic isodicentric X-chromosome in a patient with secondary amenorrhea

An isodicentric X-chromosome idic(X) (pter----q26.1::q26.1----pter) was found in lymphocytes and ovarian tissue of a 40-year-old female patient with secondary amenorrhea. No mosaicism was observed. The phenotype-karyotype correlation of our case and of previously described non-mosaic cases of idic(X) (q::q) with different breakpoints is discussed.

An isodicentric X chromosome with short arm fusion in a woman without somatic features of Turner's syndrome

A 25 year old woman with gonadal dysgenesis but no other somatic features of Turner's syndrome was found to have a 45,X/46,XidicX(p22.3) karyotype. It is postulated that because her stature is within the normal range there has been no loss of genetic material in the fusion of the two Xs. Her mother, who also had a history of menstrual problems, was found to be a 46,XX/47,XXX mosaic.

Tetraploidy with hydrops fetalis, cystic nuchal hygroma and 90, XX karyotype

In the present report we describe a mid-trimester Turner fetus with cystic nuchal hygroma, hydrops fetalis and 90, XX karyotype. This observation suggests that the development of a typical Turner syndrome in humans is apparently caused by a specific autosome/X chromosome ratio (44:1 in 45, X patients or 88:2 in the present fetus) rather than by an X-chromosome monosomy.

Specific cloning of DNA fragments absent from the DNA of a male patient with an X chromosome deletion

A method that allows the specific cloning of DNA fragments absent from patients homozygous or hemizygous for chromosomal deletions is described. The method involves phenol-accelerated competitive DNA reassociation and subsequent molecular cloning of appropriately reassociated molecules. The deletion DNA sample utilized in the competition was isolated from a patient with a minute interstitial deletion in the short arm of the X chromosome. Sheared DNA isolated from a male child, who was diagnosed as having Duchenne muscular dystrophy, chronic granulomatous disease, and retinitis pigmentosa, was combined in a 200-fold excess with Mbo I-cleaved DNA isolated from a 49, XXXXY human lymphoid cell line, and the mixture was subjected to a phenol-enhanced reassociation technique. Analysis of 81 unique segments derived from cloned reassociated DNA molecules has led to the identification of 4 (5%) human DNA fragments that are absent from the male patient's DNA. The 4 clones were localized, on the basis of hybridization with restriction nuclease-digested genomic DNA from a panel of human and human-rodent hybrid cell lines, into three regions surrounding band 21 of the short arm of the normal human X chromosome. These clones are potential linkage markers for the diseases affecting this boy. Each clone, as well as others obtainable by this approach, may also serve as a starting point in the eventual cloning of these three X-linked-disease loci. Extension of this approach to other loci, including human tumors potentially homozygous for small deletions, should also be possible.

Effect of balanced X/autosome translocations on sexual and physical development. A personal experience in 4 patients

Four different balanced X/autosome translocations: 46,X,t(X;9)(p11;q13); 46,X,t(X;12) (p11;q12); 46,X,t(X;15)(q12;p11) and 46,X,t(X;19)(q26;p12) are described in four female patients. The effect of X/autosome translocations on physical and sexual development of these women and their offspring is discussed.

Long arm deletions of the X chromosome and their symptoms: a new case (bp q24) and a short review of the literature

The clinical and cytogenetic data from a 26-year-old female with del(X)(q24----ter) are reported. This breakpoint has not been described yet. Besides this report we give a comparative summary of 24 cases from the literature with different deletions of Xq.

X long-arm deletions. A review of non-mosaic cases studied with banding techniques

A woman with secondary amenorrhoea and an X long-arm deletion (pter----q21:) is described and compared with 30 adult non-mosaic, banded cases. Approximately 50% of the patients had gonadal dysgenesis associated with a higher frequency of short stature and "Turner stigmata" than in women with indication of ovarian activity. It is suggested that preservation of bands Xq26----28 may be decisive for normal ovarian function.

Reduced fertility in women with X chromosome abnormality

One patient with the karyotype 46,X,del(X)(p11.23) and three patients with 45,X/46,XX mosaicism were fertile or showed normal ovarian function. The patient with the Xp deletion has two daughters with the same chromosomal abnormality. A study of these patients and of others reported in the literature indicated that fertility of patients with X chromosomal abnormality has a markedly shorter duration than fertility of the normal female. Menopause commonly occurred during the second and third decade of age. We suggest that such fertility is related to the rate of germ cell attrition and hypothesize that germ cell attrition in the human female is influenced by genes of multiple effect which are carried on the X chromosome. The more of these genes which are present the slower the rate of germ cell attrition.

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. Three major types: 33 reciprocal translocations (3.09%), 20 Robertsonian translocations (1.87%) and six other chromosomal abnormalities (0.56%) were found, bringing the total number of chromosomal abnormalities to 59 (5.5%) in 1068 couples under investigation. In contrast to couples with reciprocal translocations, a high excess of female over male carriers was found in the group of Robertsonian translocations. In the evaluation of chromosomal polymorphisms, only variants with particularly large paracentromeric constitutive heterochromatin blocks were taken into account, and their low frequency in the present study is therefore not comparable with that in a general population. The impact of further extensive familial investigation on genetic counseling and the follow-up of prenatal diagnosis are discussed.

Replication and inactivation of an isodicentric X: presence of an inactive centromere influences the replication patterns

An isodicentric X-chromosome (idic(X)(pter leads to q23::q23 leads to pter)) was found in a phenotypically normal 30-year-old female with symptoms of premature menopause. A study of DNA replication revealed that in a proportion of cells there was an asymmetric pattern of replication. The region with the inactive centromere had a tendency to replicate later than the portion with the functioning centromere.