Gene analysis of six cases of congenital protein S deficiency and functional analysis of protein S mutations (A139V, C449F, R451Q, C475F, A525V and D599TfsTer13)

Molecular autopsy for sudden death in Japan

Japan has various death investigation systems; however, external examinations, postmortem computed tomography, macroscopic examinations, and microscopic examinations are performed regardless of the system used. These examinations can reveal morphological abnormalities, whereas the cause of death in cases with non-morphological abnormalities can be detected through additional examinations. Molecular autopsy and postmortem genetic analyses are important additional examinations. They are capable of detecting inherited arrhythmias or inherited metabolic diseases, which are representative non-morphological disorders that cause sudden death, especially in infants and young people. In this review, we introduce molecular autopsy reports from Japan and describe our experience with representative cases. The relationships between drug-related deaths and genetic variants are also reviewed. Based on the presented information, molecular autopsy is expected to be used as routine examinations in death investigations because they can provide information to save new lives.

PROS1 variant c.1574C>T p.Ala525Val causes portal vein thrombosis with Protein S Deficiency

BACKGROUND

Protein S (PS) is a vitamin K-dependent plasma glycoprotein, and the deficiency of PS increases the risk of venous thromboembolism (VTE). PS deficiency has been found in 1.5-7% of selected groups of thrombophilic patients. However, the reported PS deficiency patients with portal vein thrombosis are scarce.

CASE REPORT AND RESULTS

Our case described a 60-year-old male patient presented portal vein thrombosis with protein S deficiency. Imaging findings of the patient revealed extensive thrombosis involving the portal vein and superior mesenteric vein. His medical history revealed lower extremity venous thrombosis 10 years ago. The level of PS activity was greatly reduced (14%, reference: 55-130%). Acquired thrombophilia caused by antiphospholipid syndrome, hyperhomocysteinemia, or malignancy were excluded. Whole exome sequencing revealed a heterozygous missense variation c.1574C>T, p.Ala525Val in the PROS1 gene. The in-silico analysis of the variant was performed by SIFT and PolyPhen-2. The results showed that the variant is a pathogenic and likely pathogenic variation respectively (SIFT, -3.404; PolyPhen-2, 0.892), the amino acid substitution A525V is presumed to result in unstable PS protein which is degraded intracellularly. Mutation site of the proband and his family members was validated by Sanger sequencing.

CONCLUSION

According to the clinical manifestation, imaging findings, protein S level, and the genetic results, a diagnosis of portal vein thrombosis with PS deficiency was made. To the best of our knowledge, our case is the second reported PS deficiency patient caused by PROS1 c.1574C>T, p.Ala525Val variant in Asia, and the case is also the only reported case with PROS1 c.1574C>T, p.Ala525Val variant presents portal vein thrombosis.

Identification of potential novel biomarkers to differentiate malignant thyroid nodules with cytological indeterminate

Background

The fine-needle aspiration (FNA) biopsy was broadly applied to clinical diagnostics evaluation for thyroid carcinomas nodule, while companioning with higher uncertainty rate (15~30%) to identify malignancy for cytological indeterminate cases. It is requirement to discover novel molecular biomarkers to differentiate malignant thyroid nodule more precise.

Methods

We employed weighted gene co-expression network analysis (WGCNA) to discover genes significantly associated with malignant histopathology for cytological indeterminate nodules. In addition, identified significantly genes were validated through another independently investigations of thyroid carcinomas patient’s samples via cBioportal and Geipa. The key function pathways of significant genes involving were blast through GenClip.

Results

Twenty-four signature genes were identified significantly related to thyroid nodules malignancy. Furthermore, five novel genes with missense mutation, FN1 (R534P), PROS1((K200I), (Q571K)), SCEL (T320S), SLC34A2(T688M) and TENM1 (S1131F), were highlighted as potential biomarkers to rule out nodules malignancy. It was identified that the key functional pathways involving in thyroid carcinomas.

Conclusion

These results will be helpful to better understand the mechanism of thyroid nodules malignant transformation and characterize the potentially biomarkers for thyroid carcinomas early diagnostics.

Ischemic Stroke with Protein S Deficiency Treated by Apixaban

A 57-year-old man with atherosclerosis obliterans was admitted with sudden-onset sensory aphasia and right hemiparesis. Brain MRI revealed acute cerebral infarctions in the left temporal lobe and magnetic resonance angiography showed occlusion of the posterior branch of the left middle cerebral artery. Transesophageal echocardiography and ultrasonography respectively confirmed a patent foramen ovale and deep vein thrombosis in the bilateral femoral veins. Blood findings showed low protein S antigen, low protein S activity, and a missense mutation of the PROS 1 gene. The administration of apixaban 10 mg BID prevented ischemic stroke recurrence and decreased the deep vein thrombosis. These outcomes indicated that apixaban may be alternative to warfarin for the secondary prevention of ischemic stroke in a patient with a protein S deficiency.