A man who inherited his SRY gene and Leri-Weill dyschondrosteosis from his mother and neurofibromatosis type 1 from his father

We report on a man with neurofibromatosis type 1 (NF1) and Leri-Weill dyschondrosteosis (LWD). His father had NF1. His mother had LWD plus additional findings of Turner syndrome (TS): high arched palate, bicuspid aortic valve, aortic stenosis, and premature ovarian failure. The proband's karyotype was 46,X,dic(X;Y)(p22.3;p11.32). Despite having almost the same genetic constitution as 47,XXY Klinefelter syndrome, he was normally virilized, although slight elevation of serum gonadotropins indicated gonadal dysfunction. His mother's karyotype was mosaic 45,X[17 cells]/46,X,dic(X;Y)(p22.3;p11.32)[3 cells].ish dic(X;Y)(DXZ1 +,DYZ1 + ). The dic(X;Y) chromosome was also positive for Y markers PABY, SRY, and DYZ5, but negative for SHOX. The dic(X;Y) chromosome was also positive for X markers DXZ1 and a sequence < 300 kb from PABX, suggesting that the deletion encompassed only pseudoautosomal sequences. Replication studies indicated that the normal X and the dic(X;Y) were randomly inactivated in the proband's lymphocytes. LWD in the proband and his mother was explained by SHOX haploinsufficiency. The mother's female phenotype was most likely due to 45,X mosaicism. This family segregating Mendelian and chromosomal disorders illustrates extreme sex chromosome variation compatible with normal male and female sexual differentiation. The case also highlights the importance of karyotyping for differentiating LWD and TS, especially in patients with findings such as premature ovarian failure or aortic abnormalities not associated with isolated SHOX haploinsufficiency.     

True hermaphroditism with ambiguous genitalia due to a complicated mosaic karyotype: clinical features,cytogenetic findings,and literature review

Abnormal recombination between the X and Y chromosomes during meiosis, occurring outside the pseudoautosomal region, can result in translocation of the SRY gene from the Y to the X chromosome, and consequently in abnormal sexual differentiation, such as the development of 46,XX males or true hermaphroditism. In this report we present clinical, cytogenetic, and molecular-cytogenetic data of a patient with ambiguous genitalia and true hermaphroditism, who had a unique mosaic karyotype, comprising three different cell lines: 46,XX(SRY+), 45,X(SRY+), and 45,X. The mosaic karyotype of our patient probably represents two different events: abnormal recombination between the X and Y chromosomes during paternal meiosis, and postzygotic loss of one of the X chromosomes. Replication studies demonstrated that in 80% of the XX cells, the SRY sequence was located on the active X chromosome. This finding suggests nonrandom X inactivation and, together with the presence of the SRY gene, explains the male phenotype of our patient. On the other hand, the presence of the 45,X cell line may have contributed to genital ambiguity. We conclude that fluorescence in situ hybridization (FISH) analysis with SRY probes is highly recommended and allows accurate diagnosis and optimal management in cases of 46,XX hermaphroditism and ambiguous genitalia.     

A man who inherited his SRY gene and Leri‐Weill dyschondrosteosis from his mother and neurofibromatosis type 1 from his father

We report on a man with neurofibromatosis type 1 (NF1) and Leri‐Weill dyschondrosteosis (LWD). His father had NF1. His mother had LWD plus additional findings of Turner syndrome (TS): high arched palate, bicuspid aortic valve, aortic stenosis, and premature ovarian failure. The proband's karyotype was 46,X,dic(X;Y)(p22.3;p11.32). Despite having almost the same genetic constitution as 47,XXY Klinefelter syndrome, he was normally virilized, although slight elevation of serum gonadotropins indicated gonadal dysfunction. His mother's karyotype was mosaic 45,X[17 cells]/46,X,dic(X;Y)(p22.3;p11.32)[3 cells].ish dic(X;Y)(DXZ1 + ,DYZ1 + ). The dic(X;Y) chromosome was also positive for Y markers PABY, SRY, and DYZ5, but negative for SHOX. The dic(X;Y) chromosome was also positive for X markers DXZ1 and a sequence < 300 kb from PABX, suggesting that the deletion encompassed only pseudoautosomal sequences. Replication studies indicated that the normal X and the dic(X;Y) were randomly inactivated in the proband's lymphocytes. LWD in the proband and his mother was explained by SHOX haploinsufficiency. The mother's female phenotype was most likely due to 45,X mosaicism. This family segregating Mendelian and chromosomal disorders illustrates extreme sex chromosome variation compatible with normal male and female sexual differentiation. The case also highlights the importance of karyotyping for differentiating LWD and TS, especially in patients with findings such as premature ovarian failure or aortic abnormalities not associated with isolated SHOX haploinsufficiency. © 2001 Wiley‐Liss, Inc.     

Léri-Weill syndrome associated with a pseudodicentric X;Y translocation chromosome and skewed X-inactivation: implications for genetic counselling

A female patient of normal intelligence with short stature and Madelung deformity is reported with Léri-Weill dyschondrosteosis and a de novo pseudodicentric X;Y translocation chromosome. The phenotype is consistent with the observed deletion of the SHOX gene by FISH and molecular studies. The Y chromosome breakpoint was in the short arm but proximal to SRY, consistent with her phenotypic sex. X-inactivation studies have shown a skewed pattern in favour of the dic (X;Y) chromosome. The ARSE gene was also deleted on the dic (X;Y) chromosome but chondrodysplasia punctata was not expressed, as CDP is recessive and ARSE escapes inactivation on the normal X chromosome. Breakpoint mapping assisted in karyotype/phenotype correlation and reproductive counselling. In particular, molecular analysis showed that the putative MRX 49 gene for mental retardation is unlikely to be deleted in this case.     

Identification of a Gypsy SHOX mutation (p.A170P) in Léri-Weill dyschondrosteosis and Langer mesomelic dysplasia

We report the clinical and molecular characteristics of 12 Spanish families with multiple members affected with Léri-Weill dyschondrosteosis (LWD) or Langer mesomelic dysplasia (LMD), who present the SHOX (short stature homeobox gene) mutation p.A170P (c.508G>C) in heterozygosity or homozygosity, respectively. In all studied families, the A170P mutation co-segregated with the fully penetrant phenotype of mesomelic limb shortening and Madelung deformity. A shared haplotype around SHOX was observed by microsatellite analysis, confirming the presence of a common ancestor, probably of Gypsy origin, as 11 of the families were of this ethnic group. Mutation screening in 359 Eastern-European Gypsies failed to identify any carriers. For the first time, we have shown SHOX expression in the human growth plate of a 22-week LMD fetus, homozygous for the A170P mutation. Although the mutant SHOX protein was expressed in all zones of the growth plate, the chondrocyte columns in the proliferative zone were disorganized with the chondrocytes occurring in smaller columnal clusters. We have also identified a novel mutation at the same residue, c. 509C>A (p.A170D), in two unrelated Spanish LWD families, which similar to A170P mutation impedes nuclear localization of SHOX. In conclusion, we have identified A170P as the first frequent SHOX mutation in Gypsy LWD and LMD individuals.     

Atypical XX male with the SRY gene located at the long arm of chromosome 1 and a 1qter microdeletion

Male individuals with a 46,XX karyotype have been designated as XX males. In 80% of the cases, the presence of Yp sequences, including the male sex-determining gene, SRY, has been demonstrated by molecular and/or fluorescence in situ hybridization (FISH) analyses. In most cases, Yp sequences are located on the short arm of the X chromosome, resulting from unequal recombination between Yp and Xp during paternal meiosis. Much less frequent in XX males is the localization of the SRY gene to an autosome. Here we report on the genetic investigation of an atypical XX male in which the SRY gene was located at the end of the long arm of chromosome 1. The patient, with a normal male phenotype, was referred for azoospermia. Conventional cytogenetic analysis showed a 46,XX karyotype. Molecular-cytogenetics (FISH) and molecular (PCR and MLPA) studies identified not only Yp-specific sequences located on the distal long arm of chromosome 1 but also the deletion of the subtelomeric 1qter region. A specific phenotype has been reported for a deletion of the 1qter region associated with mental retardation. The molecular investigation of the 1qter region showed that in our patient the microdeletion is more telomeric than in patients reported with mental retardation. To our knowledge, this is the first report of a XX male with the Yp region transferred to the terminal long arm of chromosome 1. This is also the first microdeletion of the subtelomeric 1qter region not associated with mental retardation.     

Circulating cell-free fetal DNA in maternal serum appears to originate from cyto- and syncytio-trophoblastic cells. Case report

Circulating cell-free fetal DNA in maternal serum offers an early and non-invasive method for prenatal diagnosis, but the origin of this DNA is still unknown. We report the absence of the SRY gene in maternal serum of a pregnant woman despite male genitalia at ultrasound. The karyotype was 45,X after direct trophoblast analysis and 45,X/46,Xidic(Yp) after culture and in all fetal tissues studied. Due to the absence of the SRY sequence in maternal blood and in the cytotrophoblast, we presume that free fetal DNA in this case originates from trophoblastic cells. As the case presented here is exceptional, it only has a minor impact on the accuracy of fetal sex determination by maternal serum analysis, but highlights the importance of and the necessity for the complementary ultrasonographic control.     

47,XXX male: A clinical and molecular study

We report a 53-year-old Japanese male with a 47,XXX karyotype. His clinical features included hypoplastic scrotal testes (4 ml bilaterally), normally formed small penis (3.8 cm), relatively poor pubic hair development (Tanner stage 3), gynecomastia, age-appropriate male height (159.1 cm), and mental retardation (verbal IQ of 56). Serum testosterone was markedly reduced (0.6 nmol/L). A needle biopsy showed severe testicular degeneration. FISH analysis revealed complex mosaicism consisting of (1) 47,XXX cells with a single copy of SRY (n = 177), two copies of SRY (n = 3), and no SRY (n = 1); (2) 46,XX cells with a single copy of SRY (n = 9) and no SRY (n = 3); (3) 45,X cells with no SRY (n = 5); and (4) 48,XXXX cells with a single copy of SRY (n = 1) and two copies of SRY (n = 1). PCR analysis showed the presence of Yp portion with the breakpoint between DYS264 and AMELY. Microsatellite analysis demonstrated three alleles for DMD and AR. X-inactivation analysis for the methylation status of the AR gene showed random inactivation of the three X chromosomes. The results suggest that this 47,XXX male has resulted from abnormal X-Y interchange during paternal meiosis and X-X nondisjunction during maternal meiosis. Complex mosaicism may be due to the age-related increase in mitotic nondisjunction which is prone to occur in rapidly dividing lymphocytes and to the presence of two randomly inactivated X chromosomes which may behave asynchronously during mitosis, and clinical features of this male would primarily be explained by the genetic information on the SRY (+) der(X) chromosome and his advanced age.     

PAR1 deletions downstream of SHOX are the most frequent defect in a Spanish cohort of Léri-Weill dyschondrosteosis (LWD) probands

Léri-Weill dyschondrosteosis (LWD) is a skeletal dysplasia characterized by disproportionate short stature and Madelung deformity. Mutations or deletions of the SHOX gene have been previously identified as the main cause of LWD. We recently identified the existence of a second class of pseudoautosomal region 1 (PAR1) deletions which do not include SHOX, implicated in the etiopathogenesis of LWD. The deletions map at least 30-250 kb downstream of SHOX, are variable in size and clearly cosegregate with the LWD phenotype. In order to determine the frequency of this new type of deletions in the Spanish population we analyzed the distribution of PAR1 defects, including the screening of SHOX deletions, mutations, and PAR1 deletions downstream of SHOX, in a total of 26 LWD probands by a combination of MLPA, microsatellite analysis, SNP genotyping, dHPLC, and DNA sequencing. A molecular defect was identified in 16/26 LWD patients (61.5%): 10 PAR1 deletions downstream of SHOX, four SHOX encompassing deletions, and two SHOX mutations. No apparent phenotypic differences were observed between patients with SHOX defects and those with PAR1 deletions downstream of SHOX. In the examined cohort of Spanish LWD probands, PAR1 deletions downstream of SHOX represent the highest proportion of identified mutations (38%) compared to SHOX deletions (15%) and mutations (8%). As a consequence of our findings, the screening of this region should be included in the routine genetic testing of LWD. Also, LWD patients who tested negative for SHOX defects should be re-evaluated for PAR1 deletions downstream of SHOX.     

Detection of SRY in 45, X/47, XYY mosaicism leading to phenotypic female

SRY on the Y chromosome initiates male sex determination. We tested a phenotypic female with sex chromosome mosaicism, X/XYY, for SRY expression. SRY was determined by polymerase chain reaction (PCR) amplification in genomic DNA from a female patient with a sex chromosome mosaic complement, 45, X/47, XYY, followed by sequencing analyses. The patient yielded the PCR product with predicted size and homology to the consensus sequence of SRY. The demonstration of SRY provides evidence that the female phenotype in the presence of sex chromosome mosaicism, X/XYY, may result from alterations in another part of the sex-determining pathway or downstream from SRY.     

Mitotic and meiotic instability of a telomere association involving the Y chromosome

Constitutional telomere associations and jumping translocations (JTs) are rare events and usually occur post-zygotically. We report a telomere association involving the Y chromosome which "jumped" during meiosis. A 21-year-old woman was referred for amniocentesis due to non-immune hydrops seen in a previous pregnancy. Cytogenetic analysis of the amniocytes showed a 45,X,tas(Y;15)[4]/45,X[16] karyotype with the long arm of the Y chromosome attached to the end of the short arm of chromosome 15. Parental chromosome analyzes revealed a tas(Y;19)[63]/45,X[7] karyotype in the father with Yq attached to the end of the short arm of chromosome 19. A phenotypically normal male was born and blood chromosome analysis confirmed a 45,X,tas(Y;15)[39]/45,X[10]/46,XY[1] karyotype. Two other male children have 46,XY karyotypes, which further demonstrates the instability of the tas(Y;19) in meiosis. Fluorescence in situ hybridization (FISH) analysis with probes for theY-centromere, the Yqh region, the shared Xq/Yq telomere and SRY showed hybridization on the tas(Y;19) and tas(Y;15). A chromosome 19p specific subtelomeric probe showed hybridization to the tas(Y;19) in the father. In addition, a probe for the simple telomeric sequences TTAGGG showed positive hybridization to the junction of the associations. The presence of TTAGGG telomere repeats and unique telomere sequences indicate that the Y;15 and Y;19 associations occur with no detectable loss of any sequences. The interstitial telomere sequences at the junction of the telomere association may explain the mitotic and meiotic instability of the association.     

Identification and characterization of different SHOX gene deletions in patients with Leri–Weill dyschondrosteosys by MLPA assay

Deletions of the SHOX gene (Xp22-Yp11.3) are associated with Leri–Weill dyschondrosteosys (LWD) and idiopathic short stature. It has been estimated that SHOX deletions occur in 1,000–2,000 individuals in the total population, suggesting that this alteration should be investigated in all cases with unexplained short stature. SHOX deletions are currently investigated using fluorescence in situ hybridization (FISH) or molecular analysis of intragenic CA repeats. However, both techniques show some limitations. In the present study, the use of the multiple ligation probe amplification (MLPA) assay for the identification and characterization of SHOX deletions in 15 LWD patients, 3 of which carriers of chromosome abnormalities involving the SHOX gene, is reported. MLPA analysis demonstrated the heterozygous deletion of SHOX in seven patients (46.6%), disclosing the presence of two different proximal breakpoints. In patients with abnormal karyotype, MLPA analysis was able to identify the chromosomal rearrangement, showing, in addition to the SHOX deletions, the gain or loss of other genes mapped on the X and Y chromosomes. Since MLPA analysis can be carried out on a simple buccal swab, avoiding invasive peripheral blood collection, this technique represents a fast, simple and high throughput approach in the screening of SHOX deletions, able to provide more information as compared to FISH and microsatellite analysis.     

46,XX男性综合征患者的细胞和分子遗传学研究

目的探讨SRY阳性的46,XX男性综合征患者的临床及细胞分子遗传学特征。方法对其外周血淋巴细胞进行染色体核型分析;同时提取外周血基因组DNA,进行SRY基因检测,并以正常男性及女性作对照。结果患者染色体核型为46,XX,SRY基因存在。结论基因组中存在SRY基因可能与该例46,XX男性综合征患者为男性表型密切相关,对其进行检测有利于明确性反转综合征的临床诊断,通过染色体核型分析和分子遗传学检测,可为性发育异常患者明确病因,并为其治疗提供依据。     

一例46,XY女性患者SRY基因的无义突变分析

采用ＰＣＲ－ＳＳＣＰ检测及ＤＮＡ测序技术，对一例４６，ＸＹ女性患者ＳＲＹ基因的ＨＭＧ基序进行了突变分析。结果发现在该基因的Ｓｐ引物扩增区域内存在突变。进一步的ＤＮＡ序列分析证实该突变为第６９９位碱基Ｃ被Ｔ置换，导致产生终止密码子的无义突变。结合临床表型可以认为本例患者的性反转是由于该突变所致。这一研究结果为ＳＲＹ基因是ＴＤＦ最佳候选基因的假说提供了一直接证据，有助于进一步阐明４６，ＸＹ女性发病的分     

Inherited partial X chromosome duplication in a mentally retarded male.

A mentally retarded male patient with a structurally abnormal X chromosome is reported (karyotype 46, dir dup (X)(p11.2 leads to p21.2)Y). In the normal mother a similar X chromosome duplication was found, which was preferentially inactivated. Xg blood groups were studied in the family. The findings indicated that recombination took place at maternal meiosis, as both karyotypically normal sons and the proband were Xg(a-), the mother being Xg(a+). Functional X chromosome disomy may explain clinical abnormalities in reported patients with X duplication and a normal Y chromosome.     

Molecular and cytogenetic characterization of a non-mosaic isodicentric Y chromosome in a patient with Klinefelter syndrome

We report on an adult male with Klinefelter phenotype and an isodicentric Y chromosome (47,XX,+idic(Y)(q12)), a combination which has to the best of our knowledge not been reported before. The patient was hospitalized in forensic psychiatry because of repeated delinquency, aggressive, aberrant and inappropriate behavior, and borderline intelligence. Molecular cytogenetic studies (FISH) showed that the SRY gene was present on both ends of the idicY, while there was only one signal for the Yq subtelomere probe. Molecular investigations by multiplex PCR, using STS markers covering the short and long arm of the Y chromosome did not indicate a deletion of Y chromosomal material. Molecular investigations of STR markers located on Xp22.3 and Xq28 indicated paternal origin of the additional X chromosome and an error in paternal meiosis I. Results of FISH analysis and molecular investigations are compatible with a phenotype as described for individuals with a 48,XXYY karyotype and support the findings that isodicentric Y chromosomes are frequently accompanied by other sex chromosomal abnormalities.     

Pseudodominant inheritance of Langer mesomelic dysplasia caused by a SHOX homeobox missense mutation

We report the clinical and molecular analysis in a consanguineous family in which the skeletal dysplasias Léri-Weill dyschondrosteosis (LWD) and Langer mesomelic dysplasia (LMD) both segregate. A newborn male and his mother, both with Langer mesomelic dysplasia, are described. A homozygous SHOX homeobox point mutation, C517T, was identified by direct sequencing in the proband and his mother. The same mutation was present in the heterozygous state in the proband's father and in the maternal grandmother, both of whom had features of LWD. This C to T transition is predicted to cause an arginine to cysteine amino acid change in a highly conserved region of the recognition helix of the homeodomain, which may reduce the stability of the interaction between the SHOX protein and its target DNA. In addition, the mutation may disrupt a nuclear localization signal in SHOX. This is the first SHOX point mutation identified in a case of LMD, and the first case in which parent to child transmission of LMD has been described.     

45,X/46,X,idic(Yq) mosaicism: Clinical,cytogenetic, and molecular studies in four individuals

45,X/46,X,idic(Yq) mosaicism is associated with a variety of sex phenotypes, including Ullrich-Turner syndrome (UTS), intersexuality, and complete male. It remains unclear whether the phenotypic variability results from a dilutional effect by the 45,X cell line in the primordial gonad or an abnormality of the SRY gene (SRY). We conducted cytogenetic and molecular studies on four patients with such mosaicism, two of whom had a complete male phenotype and two who had UTS. Chromosome analyses showed that the frequency of cells carrying an idic(Yq) chromosome in peripheral blood lymphocytes and skin fibroblasts was not related to the given sex phenotype. The SRY, PABY, and ZFY genes were present in all four patients. A fluorescence in situ hybridization (FISH) study showed that both a patient with a complete male phenotype and another with UTS had duplicate copies of SRY in their idic(Yq) chromosomes, whereas a patient with UTS had a single copy of the gene. These findings suggested that the coexisting 45,X cell line is more influential on the determination of the sex phenotype in individuals with 45,X/46,X,idic(Yq) mosaicism. Am. J. Med. Genet. 78:424–428, 1998. © 1998 Wiley-Liss, Inc.