Diagnosis of FOXG1 syndrome caused by recurrent balanced chromosomal rearrangements: case study and literature review.

BACKGROUND: The FOXG1 gene plays a vital role in mammalian brain differentiation and development. Intra- and intergenic mutations resulting in loss of function or altered expression of the FOXG1 gene cause FOXG1 syndrome. The hallmarks of this syndrome are severe developmental delay with absent verbal language, post-natal growth restriction, post-natal microcephaly, and a recognizable movement disorder characterized by chorea and dystonia. CASE PRESENTATION: Here we describe a case of a 7-year-old male patient found to have a de novo balanced translocation between chromosome 3 at band 3q14.1 and chromosome 14 at band 14q12 via G-banding chromosome and Fluorescence In Situ Hybridization (FISH) analyses. This rearrangement disrupts the proximity of FOXG1 to a previously described smallest region of deletion overlap (SRO), likely resulting in haploinsufficiency. CONCLUSIONS: This case adds to the growing body of literature implicating chromosomal structural variants in the manifestation of this disorder and highlights the vital role of cis-acting regulatory elements in the normal expression of this gene. Finally, we propose a protocol for reflex FISH analysis to improve diagnostic efficiency for patients with suspected FOXG1 syndrome.

Recurrent copy number variants associated with bronchopulmonary dysplasia.

BACKGROUND: Variability in the incidence and severity of bronchopulmonary dysplasia (BPD) among premature infants suggests that genetic susceptibility plays a role in pathogenesis. An assessment of copy number variants (CNV) in BPD subjects may help to identify loci that harbor genetic susceptibility factors. METHODS: We conducted a retrospective analysis of clinical DNA microarray data from our institution. We identified 19 BPD subjects, and 2 controls groups (full-term and preterm) with no lung-related disease. We reanalyzed raw data from each of these subjects to identify recurrent CNV loci in BPD subjects. RESULTS: We identified three loci (at 11q13.2, 16p13.3, and 22q11.23-q12.1) with recurrent CNV in BPD subjects. The frequency of these CNV was significantly higher in BPD subjects when compared with at least one control group. We interrogated 21 genes residing within the recurrent CNV regions for development-associated changes in expression. Fifteen genes demonstrated significant changes in expression between the pseudoglandular and canalicular stage in human lungs, a time commensurate with birth at highest risk for BPD. We also identified pathways represented by the genes present within the recurrent loci. CONCLUSION: These data identify novel loci that may harbor genes contributing to the genetic susceptibility of BPD.

Laparoscopic donor nephrectomy versus open donor nephrectomy: recipient's perspective.

Effects of laparoscopic donor nephrectomy (LDN) on graft function, especially early post-transplant, have been controversial. To assess and compare early and late graft function in kidneys procured by open and laparoscopic methods, a retrospective observational study was carried out on 37 recipients-donors who underwent LDN after introduction of this technique in February 2007 at our center, a tertiary care nephrology referral center. Demographic, immunological and intraoperative variables as well as immunosuppressive protocols and number of human leukocyte antigen (HLA) mismatches were noted. Early graft function was assessed by serum creatinine on Days two, five, seven, 14 and 28 and at the time of discharge. Serum creatinine values at three months and at one year post-transplant were considered as the surrogates of late graft function. Data obtained were compared with the data from 33 randomly selected kidney transplants performed after January 2000 by the same surgical team, in whom open donor nephrectomy was used. Pearson's chi square test, Student's t test and Mann-Whitney U test were used for statistical analysis. Early graft function (serum creatinine on Day five 2.15 mg/dL vs 1.49 mg/dL, P = 0.027) was poorer in the LDN group. Late graft function as assessed by serum creatinine at three months (1.45 mg/dL vs 1.31 mg/dL, P = 0.335) and one year (1.56 mg/dL vs 1.34 mg/dL, P = 0.275) was equivalent in the two groups. Episodes of early acute graft dysfunction due to acute tubular necrosis were significantly higher in the LDN group (37.8% vs 12.1%, Z score 2.457, P = 0.014). Warm ischemia time was significantly prolonged in the LDN group (255 s vs 132.5 s, P = 0.002). LDN is associated with slower recovery of graft function and higher incidence of early acute graft dysfunction due to acute tubular necrosis. Late graft function at one year is however comparable.

Will a peripheral blood (PB) sample yield the same diagnostic and prognostic cytogenetic data as the concomitant bone marrow (BM) in myelodysplasia?

In patients with myelodysplastic syndromes (MDS), chromosome anomalies are detected by conventional cytogenetic studies (CCS) and/or interphase fluorescence in situ hybridization (FISH) of bone marrow (BM) samples and provide prognostic and diagnostic information, which can direct therapy. Whether peripheral blood (PB) can be substituted for bone marrow in these cases and can provide the same information remains unknown. Concurrent BM and PB specimens collected from 100 patients with recently diagnosed MDS were studied using both CCS and FISH. While 68% of BM samples showed an abnormal karyotype by CCS, only 31% of PB samples were abnormal by CCS. In 12% of patients, FISH and CCS were discordant due to the inability of the FISH panel to detect all possible abnormalities. However, only one case (1%) had a cryptic abnormality detected by FISH. BM and PB FISH were discordant in 3% of cases, most likely due to the smaller clone size in PB vs. BM. While PB should not be substituted for BM at diagnosis, it is a viable alternative for monitoring patients using the appropriate FISH probe(s).