Brachytelephalangic dwarfism due to the loss of ARSE and SHOX genes resulting from an X;Y translocation

Here we report an 8-year-old male patient who had mesomelic shortening of forearms and legs, brachytelephalangia and ichthyotic skin lesions. Chromosomal analysis showed an X;Y translocation involving the short arm of the X chromosome (Xp). Fluorescence in situ hybridization (FISH) and molecular studies localized the breakpoints on Xp22.3 in the immediate vicinity of the KAL gene demonstrating deletions of steroid sulfatase (STS), arylsulfatase E (ARSE), and short stature homeo box (SHOX) genes. It was suspected that the patient was suffering from chondrodysplasia punctata because of a loss of the arylsulfatase E (ARSE) gene. However, no stippled epiphyses were to be seen in the neonatal radiograph. Interestingly, this patient is the first case with a proven loss of the ARSE gene without chondrodysplasia punctata, assuming that chondrodysplasia punctata is not an obligatory sign of ARSE gene loss. Brachytelephalangia was the only result of ARSE gene deletion in this case. The patient's mother also had dwarfism and showed Madelung deformity of the forearms. She was detected as a carrier of the same aberrant X chromosome. The male patient did not show Madelung deformity, demonstrating that Lerri-Weill syndrome phenotype may be still incomplete in children with SHOX gene deletion. The wide clinical spectrum in the male and the Leri-Weill phenotype in his mother are the results of both a deletion involving several sulfatase genes in Xp22.3 and the SHOX gene located in the pseudoautosomal region. Nevertheless, there is no explanation for the absence of chondrodysplasia punctata despite the total loss of the ARSE gene. Further studies are necessary to investigate genotype/phenotype correlation in cases with translocations or microdeletions on Xp22.3, including the ARSE and the SHOX gene loci.     

High incidence of SHOX anomalies in individuals with short stature

Objective

To study the SHOX gene and the PAR1 region in individuals with short stature.

Methods

The study involved 56 cases of dyschondrosteosis and 84 cases of idiopathic short stature (ISS). The study was designed to determine the following: the prevalence of SHOX anomalies in ISS; the frequency of Madelung deformity in individuals with SHOX anomalies; and the value of a family history of short stature in deciding whether to test for the SHOX gene.

Results

54 SHOX anomalies were observed, including 42 (68%) in the dyschondrosteosis group and 12 (15%) in the ISS group. The high frequency of SHOX anomalies in the ISS group can be explained by the large proportion of boys in this group, reflecting the difficulty in diagnosing dyschondrosteosis in young boys. Clinical evidence of Madelung deformity in six parents of ISS individuals emphasised the importance of family evaluation. Among the 54 SHOX anomalies, 33 PAR1 deletions were identified encompassing the SHOX gene (62%), one partial intragenic deletion (2%), nine deletions located downstream of the SHOX gene (16%), and 11 point mutations (20%).

Conclusions

These data emphasise the value of using microsatellite markers located within and downstream of the SHOX gene.     

Deletion of the SHOX gene in patients with short stature of unknown cause

A fluorescence in situ hybridization (FISH) study was performed in 56 patients with short stature of unknown cause in order to establish the role of deletion of the SHOX gene in this population. FISH analysis was carried out on metaphase spreads and interphase lymphocytes from blood smears using a probe specific for the SHOX gene. Deletion of SHOX was found in four patients (7.1%). No skeletal abnormalities were detected in these patients either at the physical examination or at X-rays of the upper and lower limbs. Present results indicate that SHOX plays an important role also in short stature of unknown cause, and FISH analysis appears as an easy, appropriate, and inexpensive method for the detection of SHOX deletion.     

Translocation t(11;22) in esthesioneuroblastoma

Esthesioneuroblastoma is an exceedingly rare malignant neuroectodermal tumor of olfactory epithelium origin. We have performed cytogenetic studies on a tissue culture line established from a metastatic lesion in one such patient and observed that, among several chromosomal abnormalities, the cells contained a reciprocal translocation, t(11;22)(q24;q12), indistinguishable from the one that has been reported in Ewing's sarcoma, Askin's tumor, and peripheral neuroepithelioma. The uniqueness of this marker suggests that these tumors may be derived from the same type of stem cell, with varying histopathologic and clinical manifestations.     

Genotypes and phenotypes in children with short stature: clinical indicators of SHOX haploinsufficiency

Background

Short stature affects approximately 2% of children, representing one of the more frequent disorders for which clinical attention is sought during childhood. Despite assumed genetic heterogeneity, mutations or deletions of the short stature homeobox‐containing gene (SHOX) are found quite frequently in subjects with short stature. Haploinsufficiency of the SHOX gene causes short stature with highly variable clinical severity, ranging from isolated short stature without dysmorphic features to Léri‐Weill syndrome, and with no functional copy of the SHOX gene, Langer syndrome.

Methods

To characterise the clinical and molecular spectrum of SHOX deficiency in childhood we assessed the association between genotype and phenotype in a large cohort of children of short stature from 14 countries.

Results

Screening of 1608 unrelated individuals with sporadic or familial short stature revealed SHOX mutations or deletions in 68 individuals (4.2%): complete deletions in 48 (70.6%), partial deletions in 4 (5.9%) and point mutations in 16 individuals (23.5%). Although mean height standard deviation score (SDS) was not different between participants of short stature with or without identified SHOX gene defects (–2.6 vs –2.6), detailed examination revealed that certain bone deformities and dysmorphic signs, such as short forearm and lower leg, cubitus valgus, Madelung deformity, high‐arched palate and muscular hypertrophy, differed markedly between participants with or without SHOX gene defects (p<0.001). Phenotypic data were also compared for 33 children with Turner syndrome in whom haploinsufficiency of SHOX is thought to be responsible for the height deficit.

Conclusion

A phenotype scoring system was developed that could assist in identifying the most appropriate subjects for SHOX testing. This study offers a detailed genotype‐phenotype analysis in a large cohort of children of short stature, and provides quantitative clinical guidelines for testing of the SHOX gene.     

Translocation (13;22) in a hemangiopericytoma

Cytogenetic studies on primary hemangiopericytoma tumor cells from a 28 year old woman showed a single karyotypic change: t(13;22)(q22;q11). The relationship of this aberration to previously described abnormalities of chromosome #22 in other solid tumors is discussed.     

The short stature homeobox gene SHOX is involved in skeletal abnormalities in Turner syndrome

Turner syndrome is characterized by short stature and is frequently associated with a variable spectrum of somatic features including ovarian failure, heart and renal abnormalities, micrognathia, cubitus valgus, high-arched palate, short metacarpals and Madelung deformity. Madelung deformity is also a key feature of Leri-Weill syndrome. Defects of the pseudoautosomal homeobox gene SHOX were previously shown to lead to short stature and Leri-Weill syndrome, and haploinsufficiency of SHOX was implicated to cause the short stature phenotype in Turner syndrome. Despite exhaustive searches, no direct murine orthologue of SHOX is evident. SHOX is, however, closely related to the SHOX2 homeobox gene on 3q, which has a murine counterpart, Og12x. We analysed SHOX and SHOX2 expression during human embryonic development, and referenced the expression patterns against those of Og12x. The SHOX expression pattern in the limb and first and second pharyngeal arches not only explains SHOX -related short stature phenotypes, but also for the first time provides evidence for the involvement of this gene in the development of additional Turner stigmata. This is strongly supported by the presence of Turner-characteristic dysmorphic skeletal features in patients with SHOX nonsense mutations.     

Isolated haploinsufficiency of exon 1 of the SHOX gene in a patient with idiopathic short stature

This paper reports the case of a 16-year-old woman with idiopathic short stature (ISS) who was detected to be haploinsufficient in only exon 1 of the short stature homeobox-containing (SHOX) gene by RQ-PCR and had two copies of the other six exons intact. The translation of the SHOX protein and of the SHOX promoter may be potentially affected if the deletion of exon 1 is extended further upstream. Further studies may help in determining the significance of partial exonic deletions of the SHOX gene in relation to ISS.     

Translocation (5;22) in an Askin's tumor.

A boy with a brain metastasis of an Askin's tumor was investigated. Cytogenetic studies revealed a near-diploid karyotype with monosomies of chromosomes 5 and 22 in the presence of a derivative chromosome der(5)t(5;22)(q35;q11). In particular, no involvement of chromosome 11 was seen.     

Translocation Y/5 resulting in Cri du Chat syndrome

A case of 45,X,del(5)(p14/45,X,t(Y;5)(q11;p14) mosaicism is described. The patient displays the clinical features of the Cri du Chat syndrome, together with gross malformation of the distal left arm. The presence of male sex development is consistent with the location of factor(s) controlling the male sex determination in the paracentromeric area of the Y chromosome.     

Di George anomaly associated with a de novo Y;22 translocation resulting in monosomy del(22)(q11.2)

We report on an infant, born to a diabetic mother, who presented with hypocalcemia and congenital heart disease, presurgically diagnosed by echocardiography as truncus arteriosus type I. Cytogenetic analysis showed a 45,X,-Y,-22,+der-(Y)t(Y;22) (p11.3q11.2) chromosome abnormality with del(22)(q11.2). Parental chromosomes were normal. Autopsy showed persistent truncus arteriosus type II and thymic aplasia consistent with DiGeorge anomaly. This report adds to the existing literature demonstrating an association between DiGeorge anomaly and monosomy 22q11.     

Translocation (Y;2) in childhood acute lymphoblastic leukemia.

A case of ALL in a 2 1/2-year-old boy with fatal outcome is presented. Cytogenetic analysis revealed a hypodiploid karyotype: 45,X-Y,-2,+der (2)t(Y;2),-12,i(17q),+mar. Some metaphases represented a sideline with 44 chromosomes and monosomy 8 was a consistent anomaly. These findings are rather uncommon in ALL. Hypodiploidy and the translocation, however, indicated poor prognosis in this case.     

Two cases of variant Philadelphia chromosome resulting from translocation (21;22) and (3;19;22)

Two further cases of variant Philadelphia chromosome are presented. The possible presence of a specific oncogene on the long arm of chromosome #22 is discussed.