Case Reports in Genetics最新文献

[This corrects the article DOI: 10.1155/2020/7353452.].

In this clinical report, we describe a male infant and his mother, who had similar congenital heart defects. They were both diagnosed neonatally with total anomalous pulmonary venous connection (TAPVC) in combination with other heart defects. Neither of the two had any other organ malformations or dysmorphic facial features. SNP-array identified a central 22q11.2 microdeletion in the male infant and his mother as well as in the maternal grandmother and maternal aunt. The mother and the maternal aunt additionally harbored a 15q11.2 BP1-BP2 microdeletion. The maternal grandmother was unaffected by heart disease. However, heart computed tomography scan of the maternal aunt revealed a quadricuspid aortic valve. Additionally, the maternal grandmother and the maternal aunt both had significant learning disabilities. Rarely, TAPVC has been described in patients with the common 22q11.2 microdeletions. However, to the best of our knowledge, TAPVC has not previously been reported in patients with this small central 22q11.2 microdeletion. Haploinsufficiency of TBX1 was originally thought to be the main cause of the 22q11.2 microdeletion syndrome phenotype, but TBX1 is not included in the atypical central 22q11.2 microdeletion. Previous reports have suggested an association between TAPVC and the 15q11.2 BP1-BP2 microdeletion. Our report does not support this association as the maternal aunt, who harbors both microdeletions, is unaffected by TAPVC, and the male infant affected by TAPVC does not harbor the 15q11.2 BP1-BP2 microdeletion. Our findings support that genes located in the central 22q11.2 region are important for heart development and that haploinsufficiency of these genes plays a crucial role in the development of the rare heart defect TAPVC.

Intracranial undifferentiated pleomorphic sarcoma remains a rare pathology within the sarcoma literature that may arise primarily or secondary after radiation therapy. Despite first-line treatment with maximal surgical resection, followed by nonstandardized adjuvant chemotherapy/radiation regimens, clinical prognosis remains exceedingly poor. Furthermore, there is a lack of genetic or molecular characterization to guide potential for targeted therapies. We present genomic analysis of a radiation-induced intracranial undifferentiated pleomorphic sarcoma in an 83-year-old woman with notable KIT and PDGFRA alterations. Further similar genomic studies of intracranial pleomorphic sarcoma are needed to develop better therapies for this rare but challenging disease entity.

We report a 15-year-old boy with cat-eye syndrome (CES) without short stature or intellectual disorder. The boy was confirmed by cytogenetic and high-resolution chromosome microarray analysis (CMA). The G-banding karyotype confirmed the de novo of the patient. Also, the CMA result showed 1.76 Mb tetrasomy of proximal 22Q11.1 ⟶ 22Q11.21 consistent with CES {arr22q11.1q11.21 (16,888,899-18,644,241) X4}, a typical small type I CES chromosome. The patient has many of the basic characteristics of CES; however, he is taller than his peers instead of shorter. It is rarely reported in the past since short stature is a common feature of this syndrome. Furthermore, the boy has no intellectual disorder and attends a normal school since he was six-year-old. What bothered him most were recurrent respiratory infections, retromicrognathia, and heart defects.

Introduction: Ataxia telangiectasia is a rare genetic condition with an estimated prevalence of 1 in 40,000-100,000 live births. This condition predominantly affects the nervous and immune systems. It is characterized by progressive ataxia beginning from early childhood. The neurological deficit associated with this condition affects one's balance, coordination, walking, and speech and can be accompanied by chorea, myoclonus, and neuropathy. They may also have ocular telangiectasias and high levels of blood alpha-fetoprotein (AFP). The ataxia telangiectasia mutated gene (ATM) is associated with this condition and codes for the ATM protein which is a phosphatidylinositol 3-kinase. This gene occupies 150 kb on chromosome 11q22-23 and contains 66 exons encoding a 13 kb transcript. ATM is a relatively large protein with a molecular weight of 350 kDa and 3,056 amino acids.

Methods: Four patients of Sri Lankan origin presenting with features suggestive of ataxia telangiectasia were referred to our genetics center for specialized genetic counseling and testing. Whole-exome sequencing followed by Sanger sequencing was used to confirm the candidate variants. Protein modeling and genotype to phenotype correlation was performed in the identified variants.

Results: We observed 6 novel ATM gene variants in four patients with ataxia telangiectasia. The identified variants are as follows: homozygous c.7397C > A (p.Ala2466Glu) and c.510_511delGT (p.Tyr171fs) and compound heterozygous c.5347_5350delGAAA (p.Glu1783fs), c.8137A > T (p.Arg2713 ^∗ ) and c.1163A > C (p.Lys388Thr), and c.5227A > C (p.Thr1743Pro). Variant analysis was followed by modeling of the native and altered protein structures.

Conclusion: We report novel ATM gene variants that have implications on the molecular diagnosis of ataxia telangiectasia.

Parkinson's disease (PD) is the second most common neurodegenerative disorder after Alzheimer disease. Five to ten percent of patients have monogenic form of the disease, while most of sporadic PD cases are caused by the combination of genetic and environmental factors. Microtubule-associated protein tau (MAPT) has been appointed as one of the most important risk factors for several neurodegenerative diseases including PD. MAPT is characterized by an inversion in chromosome 17 resulting in two distinct haplotypes H1 and H2. Studies described a significant association of MAPT H1j subhaplotype with PD risk, while H2 haplotype was associated with Parkinsonism, particularly to its bradykinetic component. We report here an isolated case displaying an akinetic-rigid form of PD, with age of onset of 41 years and a good response to levodopa, who developed dementia gradually during the seven years of disease progression. The patient does not carry the LRRK2 G2019S mutation, copy number variations, nor pathogenic and rare variants in known genes associated with PD. MAPT subhaplotype genotyping revealed that the patient has the H1j/H2 diplotype, his mother H1j/H1j, his two healthy brothers H1j/H1v and his deceased father was by deduction H1v/H2. The H1j/H2 diplotype was shown in a total of 3 PD patients among 80, who also did not have known PD-causing mutation and in 1 out of 92 healthy individual controls. The three patients with this diplotype all have a similar clinical phenotype. Our results suggest that haplotypes H1j and H2 are strong risk factor alleles, and their combination could be responsible for early onset of PD with dementia.

Background: Autosomal dominant retinitis pigmentosa (adRP) is a rare cause of progressive visual impairment in young patients and is frequently a result of RHO gene mutations. p.Thr58Arg rhodopsin mutation leads to misfolding of rhodopsin, subsequent accumulation in the endoplasmic reticulum, and leads to consecutive atrophy of photoreceptor cells through apoptosis.

Materials and methods: We describe multimodal imaging findings in a 58-year-old female with adRP due to a c.173 C > G, p.Thr58Arg rhodopsin mutation (confirmed on genotyping), including ultra-wide-field fundus autofluorescence (UWF-FAF), color scanning laser ophthalmoscopy, structural optical coherence tomography (OCT), OCT-angiography (OCT-A), electroretinography (ERG), and visual field testing (HVF). Additionally, we compare the patient's phenotypic findings to those of her offspring, who was also affected by adRP.

Results: The 58-year-old female and her son with symptoms of nyctalopia and decreased vision showed macular pigmentary changes in a bull's-eye pattern along with bone spicules in periphery with retinal atrophy. Genotyping confirmed p.Thr58Arg rhodopsin mutation. Wide area of dystrophic retina was noted on UWF-FAF, along with corresponding atrophy of photoreceptor layer on OCT. OCTA revealed complete nonperfusion of the superficial capillary plexus in areas of retinal dystrophy. ERG revealed increased latency and decreased amplitudes; HVF revealed constriction of visual fields consistent with retinal findings.

Conclusions: Multimodal imaging is extremely helpful in delineating the extent of retinal dystrophy and comparable to ERG for monitoring of progress in retinitis pigmentosa. Photoreceptor layer thickness (measured with OCT) strongly correlated with ERG and can be used as a secondary surrogate for monitoring the disease progress.

Salivary gland tumors (SGTs) of parotid origin are a group of diverse neoplasms which are difficult to classify due to their rarity and similar morphologic patterns. Chromosome analysis can detect clonal abnormalities, and array comparative genomic hybridization (aCGH) analysis can define copy number alterations (CNAs) from tumor specimens. Of the 19 cases of various types of SGTs submitted for cytogenomic analyses, an abnormal clone was detected in nine cases (47%), and CNAs were detected in 14 cases (74%). Recurrent rearrangements involving the PLAG1 gene at 8q12, recurrent CNAs including deletions of 6q, 9p (CDKN2A), and 17p (TP53), loss of Y chromosome, and gain of chromosome 7 were defined from these cases. Combined karyotyping and aCGH analyses could improve diagnostic yield. Future study for more precisive correlation of SGT classification with cytogenomic abnormalities will facilitate better diagnosis and treatment.

Background: Chordomas are rare malignant bone tumors preferentially forming in neuraxial bones. Chondroid chordoma is a subtype of chordoma. Chordomas reportedly present as synchronous multiple lesions upon initial diagnosis. However, it remains unknown whether these lesions are multicentric or metastatic multiple chordoma tumors. Case Presentation. Here, we present the case of a 57-year-old woman with multiple chordomas at the clivus, C6, and T12 upon initial presentation. Sequential surgeries and radiotherapy were performed for these lesions, and postoperative histological diagnosis revealed that all lesions were chondroid chordomas. Next-generation sequencing revealed that these lesions harbored a common somatic mutation in epidermal growth factor receptor (EGFR), c.3617A>C, which is not considered a pathogenic chordoma mutation, thus indicating that these lesions were not multicentric but rather multiple metastatic tumors. Subsequent multiple metastases to the lung and appendicular and axial bones were detected 15 months after the initial surgery. Recurrent lesions at the clivus progressed despite EGFR-targeted therapy, surgery, and radiotherapy.

Conclusion: The present evidence indicates that multiple chordomas in this case were caused by multiple metastases rather than multicentric lesions. Multiple presentations of chordoma imply systemic dissemination of tumor cells, and novel efficient systemic therapy is required to treat this disease.