Fetus with a 9q22q34 interstitial deletion and hygroma

Nuchal translucency thickness in the prediction of unbalanced translocations

OBJECTIVE

The aim of this study was to assess the role of nuchal translucency (NT) in the prediction of unbalanced translocation in offspring of couples in which one of the parents is a balanced translocation carrier.

MATERIAL AND METHODS

From January 1996 to December 2012, fetal NT was measured before chorionic villus sampling in 86 pregnancies referred because of parental balanced translocation.

RESULTS

No significant differences in pregnancy characteristics and in NT expressed in millimetres or in multiples of the median (MoMs) were observed between the 41 fetuses with a normal karyotype [1.72 mm, 95% confidence interval (CI): 1.49-1.96; 1.14 MoM; 95% CI: 1.01-1.26], the 38 fetuses with balanced translocations (1.78 mm, 95% CI: 1.44-2.12; 1.22 MoM; 95% CI: 1.01-1.43) and the 7 fetuses with unbalanced translocations (2.21 mm, 95% CI: 1.33-3.09; 1.59 MoM; 95% CI: 0.72-2.45). The proportions of fetuses with NT above 95th centile in the three groups were 9.1% in fetuses with normal karyotype, 18.4% in balanced translocations and 28.6% in unbalanced translocations, not significantly different.

CONCLUSION

Although a trend to an increased NT was observed in fetuses with unbalanced translocation, no significant differences were reached. According to our results, a normal NT evaluation should not preclude the performance of CVS in pregnancies of balanced translocation parents.

Multiple tumor types including leiomyoma and Wilms tumor in a patient with Gorlin syndrome due to 9q22.3 microdeletion encompassing the PTCH1 and FANC-C loci

Gorlin syndrome or nevoid basal cell carcinoma syndrome (NBCCS) is an autosomal dominant condition mainly characterized by the development of mandibular keratocysts which often have their onset during the second decade of life and/or multiple basal cell carcinoma (BCC) normally arising during the third decade. Cardiac and ovarian fibromas can be found. Patients with NBCCS develop the childhood brain malignancy medulloblastoma (now often called primitive neuro-ectodermal tumor [PNET]) in 5% of cases. The risk of other malignant neoplasms is not clearly increased, although lymphoma and meningioma can occur in this condition. Wilms tumor has been mentioned in the literature four times. We describe a patient with a 10.9 Mb 9q22.3 deletion spanning 9q22.2 through 9q31.1 that includes the entire codifying sequence of the gene PTCH1, with Wilms tumor, multiple neoplasms (lung, liver, mesenteric, gastric and renal leiomyomas, lung typical carcinoid tumor, adenomatoid tumor of the pleura) and a severe clinical presentation. We propose including leiomyomas among minor criteria of the NBCCS.

Microdeletion 9q22.3 syndrome includes metopic craniosynostosis, hydrocephalus, macrosomia, and developmental delay

Basal cell nevus syndrome (BCNS), also known as Gorlin syndrome (OMIM #109400) is a well-described rare autosomal dominant condition due to haploinsufficiency of PTCH1. With the availability of comparative genomic hybridization arrays, increasing numbers of individuals with microdeletions involving this locus are being identified. We present 10 previously unreported individuals with 9q22.3 deletions that include PTCH1. While 7 of the 10 patients (7 females, 3 males) did not meet strict clinical criteria for BCNS at the time of molecular diagnosis, almost all of the patients were too young to exhibit many of the diagnostic features. A number of the patients exhibited metopic craniosynostosis, severe obstructive hydrocephalus, and macrosomia, which are not typically observed in BCNS. All individuals older than a few months of age also had developmental delays and/or intellectual disability. Only facial features typical of BCNS, except in those with prominent midforeheads secondary to metopic craniosynostosis, were shared among the 10 patients. The deletions in these individuals ranged from 352  kb to 20.5  Mb in size, the largest spanning 9q21.33 through 9q31.2. There was significant overlap of the deleted segments among most of the patients. The smallest common regions shared among the deletions were identified in order to localize putative candidate genes that are potentially responsible for each of the non-BCNS features. These were a 929  kb region for metopic craniosynostosis, a 1.08  Mb region for obstructive hydrocephalus, and a 1.84  Mb region for macrosomia. Additional studies are needed to further characterize the candidate genes within these regions.

9q22 Deletion--first familial case

Background

Only 29 cases of constitutional 9q22 deletions have been published and all have been sporadic. Most associate with Gorlin syndrome or nevoid basal cell carcinoma syndrome (NBCCS, MIM #109400) due to haploinsufficiency of the PTCH1 gene (MIM *601309).

Methods and Results

We report two mentally retarded female siblings and their cognitively normal father, all carrying a similar 5.3 Mb microdeletion at 9q22.2q22.32, detected by array CGH (244 K). The deletion does not involve the PTCH1 gene, but instead 30 other gene,s including the ROR2 gene (MIM *602337) which causing both brachydactyly type 1 (MIM #113000) and Robinow syndrome (MIM #268310), and the immunologically active SYK gene (MIM *600085). The deletion in the father was de novo and FISH analysis of blood lymphocytes did not suggest mosaicism. All three patients share similar mild dysmorphic features with downslanting palpebral fissures, narrow, high bridged nose with small nares, long, deeply grooved philtrum, ears with broad helix and uplifted lobuli, and small toenails. All have significant dysarthria and suffer from continuous middle ear and upper respiratory infections. The father also has a funnel chest and unilateral hypoplastic kidney but the daughters have no malformations.

Conclusions

This is the first report of a familial constitutional 9q22 deletion and the first deletion studied by array-CGH which does not involve the PTCH1 gene. The phenotype and penetrance are variable and the deletion found in the cognitively normal normal father poses a challenge in genetic counseling.

Fine mapping of breakpoints in two unrelated patients with rare overlapping interstitial deletions of 9q with mild dysmorphic features

Approximately, 20 cases of interstitial deletions of 9q have been reported in the literature spanning the breakpoints from 9q21 to 9q34. Unlike the 9q subtelomeric deletions, the interstitial deletions do not demonstrate a specific recognizable phenotype, although the majority of patients had microcephaly. Lack of precise molecular delineation of the extent of deletions in the published cases makes it difficult to develop an accurate genotype-phenotype correlation. We report on fine mapping of breakpoints using the Affymetrix Human Mapping 500K Array Set in two unrelated female patients with overlapping de novo deletion in 9q. SNP oligonucleotide microarray analysis (SOMA) indicated these to be relatively large deletions with Patient 1 having a 6.47 Mb deletion (>60 genes) spanning 9q32-q33.2 and Patient 2 having a 9.68 Mb deletion (>20 genes) localized to 9q31.1-q33.1. FISH analysis with BAC clones localized to the breakpoints showed discrepant results in Patient 1. Based on the review of previously reported interstitial 9q deletion patients and our patients, the minimal region of overlap (MRO) appears to encompass the 9q32 region and a phenotype characterized by microcephaly, neurological dysfunction and facial dysmorphism can be deduced. Our study shows the investigative nature of the latest array technology and the limitations of this technology in the accurate delineation of breakpoints.

Nuchal Translucency Thickness in Fetuses With Chromosomal Translocation at 11–12 Weeks of Gestation

OBJECTIVE

To investigate differences in nuchal translucency thickness among fetuses in which either parent is a balanced chromosome translocation carrier.

METHODS

A prospective observational study was conducted with 98 pregnant women in the first trimester. Each had been advised to undergo chorionic villous sampling for fetal karyotyping for the indication of parental balanced chromosomal translocation. Fetal nuchal translucency measurement was performed before chorionic villous sampling. Nuchal translucency thickness was compared among fetuses with 3 kinds of karyotypes: normal, balanced translocation, and unbalanced translocation.

RESULTS

There were no differences in maternal age, gestational age, parity, and number of previous miscarriages among pregnancies with normal karyotype, balanced chromosomal translocation, and unbalanced chromosomal translocation. A significantly greater nuchal translucency thickness was shown in the unbalanced chromosomal translocation group (2.9 +/- 1.2 mm) compared with both the balanced chromosomal translocation group (1.0 +/- 0.6 mm; P < .001) and the normal karyotype group (1.0 +/- 0.8 mm; P < .001). No statistically significant difference in nuchal translucency thickness was found between the balanced chromosomal translocation group and normal karyotype group (P = .991). Nuchal translucency thickness did not differ significantly between unbalanced chromosomal translocation dependent on paternal origin and that dependent on maternal origin (P = .611).

CONCLUSION

In fetuses with unbalanced chromosomal translocation, nuchal translucency thickness tends to be greater, and thus nuchal translucency measurement might be considered part of the investigation for pregnancies marked by a parental balanced chromosomal translocation.

Prenatal diagnosis ofde novo proximal interstitial deletion of 9q and review of the literature of uncommon aneuploidies associated with increased nuchal translucency

OBJECTIVES

To present the prenatal diagnosis and molecular cytogenetic analysis of de novo proximal interstitial deletion of 9q and to review the literature of uncommon aneuploidies associated with increased nuchal translucency (NT).

CASE

Obstetric ultrasound at 11 weeks' gestation revealed an increased NT thickness of 6.6 mm in a 31-year-old primigravid woman. At 13 weeks' gestation, repeat ultrasound examinations revealed a normal NT thickness of 1.8 mm. The subcutaneous nuchal fluid accumulation was no longer present at the following ultrasound scans. An amniocentesis was performed at 18 weeks' gestation.

RESULTS

Cytogenetic analysis revealed a karyotype of 46,XX,del(9)(q21.1q22.2). The parental karyotypes were normal. At 21 weeks' gestation, a 442-g female fetus was delivered with low-set ears, hypertelorism, and a thick nuchal fold. The parental origin of the interstitial deletion of 9q was analyzed with polymorphic DNA markers. With the microsatellite markers D9S238 (9q13), D9S889 (9q21.11), and D9S253 (9q22.2), two alleles inherited from the parents were seen in the proband, but with markers D9S1780 (9q21.31), D9S303 (9q21.32), D9S252 (9q21.33), and D9S316 (9q22.1), only one maternal allele was present. The deletion was of paternal origin.

CONCLUSIONS

Fetuses with uncommon aneuploidies may manifest increased NT in the first trimester. The present case provides evidence for a correlation between increased NT and interstitial 9q deletion. Prenatal identification of increased NT should alert subtle structural chromosome aberrations and prompt high-resolution karyotyping.

Intracranial dural venous anomalies in familial cervical cystic hygroma

This report describes a 3-year-old male with a familial cervical cystic hygroma and intracranial dural venous abnormalities consisting of a falcine sinus between the superior sagittal and the straight sinus with a rudimentary posterior part of the superior sagittal sinus; a prominent occipital sinus with narrowed transverse sinuses; and no intraparenchymal vascular abnormality. We hypothesize that a genetic factor that resulted in familial cervical cystic hygromas may also have caused the intracranial dural venous anomalies.

Interstitial deletion 9q22.32-q33.2 associated with additional familial translocation t(9;17)(q34.11;p11.2) in a patient with Gorlin-Goltz syndrome and features of Nail-Patella syndrome

The phenotype of Gorlin-Goltz syndrome or basal cell nevus syndrome (BCNS, #109400, OMIM), a Mendelian trait due to PTCH mutations has been reported in a few cases of interstitial deletion of chromosome 9q. We present an 11-year-old girl with clinical features consistent with BCNS including bridging of sella turcica, biparietal bossing, downward slanting palpebral fissures, mandible prognathism, pectus excavatum, thumb abnormalities, occult spina bifida at L5-S4, numerous basal cell nevi, and single basal cell carcinoma. Cytogenetic analysis using high-resolution banding techniques and fluorescence in situ hybridization (FISH) revealed interstitial chromosome deletion 9q22.32-q33.2 involving the PTCH gene as a secondary breakage event to a chromosome translocation t(9;17)(q34.1;p11.2)mat. Further FISH studies showed the translocation breakpoint on 9q34.11 maps proximal to ABL, between the BAC clone RP11-88G17 and the LMX1B gene. The latter gene encodes a transcription factor, in which loss of function mutations are responsible for the nail-patella syndrome (NPS, #161200 OMIM). Interestingly, some features of our proband (e.g., bilateral patellar dysplasia and abnormal clavicular shape), as well as her healthy sister who carries the same translocation, are also found in patients with NPS. The chromosome 17p11.2 breakpoint maps in the Smith-Magenis syndrome common deletion region, within two overlapping BAC clones, CTD-2354J3 and RP11-311F12.