Veronica Bertini

Isolated 6q terminal deletions: an emerging new syndrome.

Deletions of the distal part of the 6q chromosome have not been associated with a clearly distinctive and recognizable phenotype. In order to determine if a “6q terminal deletion syndrome” could be delineated, we compared the phenotype of two new cases with those patients reported in literature presenting with a similar deletion. Cases with more complex karyotypes were excluded. The deletion in our patients was accurately analyzed by loss of heterozygosity (LOH) and fluorescence in situ hybridization (FISH) with a panel of probes located around the putative breakpoint. Interestingly, the breakpoints were located in 6q26 in both our patients, distally to clone RP11‐150P20 and proximally to clone RP11‐152P19, with a deletion size of approximately 8 Mb. The breakpoints fall within the fragile site FRA6E. From a careful evaluation of the selected patients, a common phenotype emerged, including psychomotor retardation, hypotonia, seizures, short neck, and typical facial anomalies, along with nonspecific anomalies. While these features are shared by other chromosome syndromes and are not sufficient on their own for a clinical diagnosis, when considered together, the pattern can allow the identification of the “6q terminal deletion syndrome.” Moreover, the potential role of FRA6E in generating these deletions is suggested.

Homeobox HOXA10 gene analysis in cryptorchidism

BACKGROUND In male mice, targeted disruption of the homeobox gene hoxa10 causes cryptorchidism and infertility. Genetic alterations in exon 1 of HOXA10 have been found in a high number of boys with cryptorchidism. AIM To evaluate whether mutations of HOXA10 can be a common cause of cryptorchidism. PATIENTS AND METHODS Genomic DNA was extracted from 18 patients with cryptorchidism (age 7-44 years; unilateral n = 13; no familial cases) and 28 healthy controls (age 9-39 years). HOXA10 was amplified by PCR and all coding sequences of exon 1 and 2 were sequenced. The PCR products were digested by ScrFI restriction enzyme and the restriction fragments obtained were analyzed on 2% agarose gel. RESULTS One silent polymorphism, G-->A substitution at position 1203, was detected in 2/18 patients (11.1%). The same polymorphism was detected in 3/28 controls (10.7%). CONCLUSIONS These data on HOXA10 analysis indicate that alterations of this gene may be more rare in males with cryptorchidism than previously suggested. This finding agrees with the rare occurrence of INSL3 gene mutations in human cryptorchidism, but needs to be confirmed in a larger series of selected patients.

Molecular cytogenetic definition of a translocation t(X;15) associated with premature ovarian failure

OBJECTIVE To characterize the breakpoints of a t(X;15) found in a woman with premature ovarian failure (POF). DESIGN Case report. SETTING Molecular and cytogenetics unit in a university-affiliated hospital. PATIENT(S) A 19-year-old infertile woman presenting with a normal female phenotype but primary amenorrhea. INTERVENTION(S) Molecular cytogenetic analyses and genetic counseling. MAIN OUTCOME MEASURE(S) Translocation t(X;15) defined by fluorescence in situ hybridization (FISH) and array comparative genomic hybridization (array CGH). RESULT(S) Chromosome and FISH analysis revealed 46,XX, t(X;15)(Xq22.1;p11); the active X was translocated and had been inherited from her mother. Detailed molecular characterization by FISH showed that the NXF5 (nuclear RNA export factor 5) gene was contained in the clone spanning the breakpoint on the X chromosome. CONCLUSION(S) The NXF5 gene is an appealing candidate for POF because it shows functional homology with the FMR1 (fragile X mental retardation 1) gene. Further analyses of its expression as well as mutation screening in other POF patients will help to elucidate its role.

Characterization of the phenotype and definition of the deletion in a new patient with ring chromosome 22

The clinical phenotype of patients with ring chromosome 22 includes mental retardation with severe language impairment, hypotonia, and dysmorphic facial features. In recent years an increasing number of patients with microscopic as well as cryptic terminal deletion involving band 22q13 have been described and their phenotype shows clinical features overlapping with patients with ring chromosome 22. Loss of DNA in the 22q13.3 region may lead to a clinically recognizable syndrome named “22q13.3 deletion syndrome.” We report a patient with a ring chromosome 22 who has hypotonia, profound mental retardation, language impairment, dysmorphic features, and behavioral disorders. To check if the critical region responsible for “22q13.3 deletion syndrome” was absent in this ring, a fluorescent in situ hybridization (FISH) analysis using a probe corresponding to the ARSA locus was performed. In our patient, only one ARSA signal could be detected, indicating that the deletion encompassed the critical 22q13.3 region. A more detailed analysis of the deletion extent then was performed using a panel of fluorescent probes located within 22q13. These experiments allowed the identification of the breakpoint between CTA‐299D3 and RP5‐925J7 probe, located in 22q13.32. Deletion extent could be estimated to be about 2.5 Mb, and this larger deletion may explain the severity of clinical features observed in our patient.

Ring chromosome 21 and reproductive pattern: a familial case and review of the literature

OBJECTIVE To characterize a ring chromosome 21 found in an infertile woman and in her mother. DESIGN Case report. SETTING Molecular and cytogenetics unit in a university-affiliated hospital. PATIENT(S) A 32-year-old infertile woman, presenting a normal female phenotype without clinical signs or major dysmorphisms. INTERVENTION(S) Molecular cytogenetic analyses and genetic counseling. MAIN OUTCOME MEASURE(S) Structure of chromosome ring 21 (r21) was better defined by fluorescent in situ hybridization and array comparative genomic hybridization. RESULT(S) Proband chromosomal analysis detected a mosaicism with three cell lines: one with a chromosome ring 21 (94%), one 45,XX, -21 (4%), and one with a dicentric ring (2%). This ring was inherited from her mother, whose karyotype was 46,XX, r(21)/45,XX, -21 [98%, 2%]. In both cases, the ring breakpoint was in band 21q22.3, with a deletion of about 3.4 Mb. CONCLUSION(S) When a new case of r(21) is found, an accurate molecular definition of the deletion extent is mandatory and prenatal diagnosis should be suggested in case of pregnancy. Even if a strict genotype-phenotype correlation is not easy, mainly owing to a paucity of molecularly defined cases and to the mosaicism problems, prenatal investigations allow excluding chromosome 21 nondisjunction or rearrangements of r(21) that can have a dramatic effect on the fetus phenotype.

Acro‐cardio‐facial syndrome: A microdeletion syndrome?

Acro‐cardio‐facial syndrome (ACFS) is an infrequently reported, variable condition characterized by split‐hand and split‐foot malformation and congenital heart defect (CHD), along with cleft lip and palate, genital anomalies, unusual face and intellectual disability. An autosomal recessive pattern of inheritance has been suggested because of affected sibs born to unaffected parents and parental consanguinity; the cause is unknown. We describe a newborn with the clinical manifestations of ACFS in whom a deletion of the region 6q21‐q22.3 was detected by array CGH. We compare the clinical features of the present patient with earlier reported patients with similar 6q deletions and patients diagnosed with ACFS. The similarities between these patient groups suggest that ACFS may be a microdeletion syndrome caused by loss of the 6q21‐22.3 region. The recurrence in families may be explained by prenatal germline mosaicism. Alternatively, ACFS may be a genetically heterogeneous disorder which can also be caused by biallelic mutations of an autosomal recessive gene.

EML4-ALK translocation in both metachronous second primary lung sarcomatoid carcinoma and lung adenocarcinoma: a case report.

The EML4-ALK gene translocation was described in a non small cell lung cancer (NSCLC) subset, with a potent oncogenic activity. It represents one of the newest molecular targets in NSCLC. We report on the case of a metachronous second primary lung sarcomatoid carcinoma after resection of lung adenocarcinoma both with ALK translocation, in a non-smoking patient. EML4-ALK rearrangement was detected with immunohistochemistry and confirmed with fluorescent in situ hybridization (FISH). To assess the clonal relationship between the two tumors, both adenocarcinoma and sarcomatoid carcinoma were analyzed by array comparative genomic hybridization (aCGH). We observed different genomic profiles suggesting that the tumors arose independently and were thus multiple primaries. To the best of our knowledge, this is the first report concerning the presence of the EML4-ALK fusion gene in a sarcomatoid carcinoma of the lung. Crizotinib, the ALK tyrosine kinase inhibitor, is highly effective in ALK-rearranged NSCLC; therefore, it may be imperative to identify all NSCLC that harbor ALK translocations in the near future. Starting from our evidence, tumors with sarcomatoid histology may need to be screened for the presence of EML4-ALK rearrangement.

Myelodysplastic syndromes: advantages of a combined cytogenetic and molecular diagnostic workup

In this study we present a new diagnostic workup for the myelodysplastic syndromes (MDS) including FISH, aCGH, and somatic mutation assays in addition to the conventional cytogenetics (CC). We analyzed 61 patients by CC, FISH for chromosome 5, 7, 8 and PDGFR rearrangements, aCGH, and PCR for ASXL1, EZH2, TP53, TET2, RUNX1, DNMT3A, SF3B1 somatic mutations. Moreover, we quantified WT1 and RPS14 gene expression levels, in order to find their possible adjunctive value and their possible clinical impact. CC analysis showed 32% of patients with at least one aberration. FISH analysis detected chromosomal aberrations in 24% of patients and recovered 5 cases (13.5%) at normal karyotype (two 5q- syndromes, one del(7) case, two cases with PDGFR rearrangement). The aGCH detected 10 “new” unbalanced cases in respect of the CC, including one with alteration of the ETV6 gene. After mutational analysis, 33 patients (54%) presented at least one mutation and represented the only marker of clonality in 36% of all patients. The statistical analysis confirmed the prognostic role of CC either on overall or on progression-free-survival. In addition, deletions detected by aCGH and WT1 over-expression negatively conditioned survival. In conclusion, our work showed that 1) the addition of FISH (at least for chr. 5 and 7) can improve the definition of the risk score; 2) mutational analysis, especially for the TP53 and SF3B1, could better define the type of MDS and represent a “clinical warning”; 3) the aCGH use could be probably applied to selected cases (with suboptimal response or failure).

Short Stature in Isodicentric Y Chromosome and Three Copies of the SHOX Gene: Clinical Report and Review of Literature.

Short stature homeobox gene (SHOX) mutations and pseudoautosomal region 1 (PAR1) deletions encompassing SHOX are known causes of Léri-Weill dyschondrosteosis and isolated short stature, while 3 copies of SHOX in cases with triple sex chromosome constitution are responsible for tall stature. Duplications involving SHOX have been rarely reported, and they were found in individuals with short, normal and tall stature. An adopted boy with short stature, isodicentric Y chromosome and 3 copies of SHOX is described. Normal growth hormone (GH) secretion and insulin-like growth factor 1 (IGF1) increase during an IGF1 generation test were found, ruling out impaired GH-IGF1 axis. No other organic or psychiatric causes of impaired growth were found. GH treatment improved linear growth, as reported in children with SHOX haploinsufficiency. This new report and the review of literature support that SHOX duplication may cause short stature, especially in those children with duplications of the 5′SHOX regulatory elements. Chromosome analysis and detailed molecular characterization of the duplicated region should be warranted in individuals with SHOX duplications in order to investigate the presence of occult chromosome imbalance. Additional reports and follow-up till adult height are needed to give conclusions on long-term efficacy and safety of GH treatment in short children with SHOX duplication.

Long-term growth hormone treatment in a boy with 45,X/46,X,idic(Yp) mixed gonadal dysgenesis: comparison with growth pattern of an untreated patient

BACKGROUND: Mixed gonadal dysgenesis (MGD) is a rare disorder. Short stature is a well known feature of this condition. Although growth hormone (GH) treatment has been suggested to treat growth impairment, conflicting data surround this issue. CASE REPORT: We report on long-term growth hormone (GH) therapy at pharmacological doses (0.33 mg/kg/week) in a boy (age 4.6 years) with MGD [karyotype 45,X/46,X,idic(Yp)]. An untreated boy of similar karyotype and growth delay served as control. The treated boy showed a progressive improvement of stature during GH administration. His height completely normalized after 6.5 years of treatment and he reached his target height centile before puberty onset. In the untreated boy, no improvement of growth pattern was found. CONCLUSIONS: We conclude that short boys with MGD and 45,X/46,X,idic(Yp) karyotype may benefit from early GH therapy at pharmacological doses. Evaluation of larger patient samples and additional follow-up till final height are needed to reach definitive conclusions as to the optimal growth-promoting therapy for this disorder of sex development.