POS0393 ASSOCIATION BETWEEN GENETICALLY PREDICTED EXPRESSION OF TPMT AND AZATHIOPRINE ADVERSE EVENTS IN PATIENTS WITH INFLAMMATORY CONDITIONS

Background

Azathioprine is a widely used immunosuppressant for the treatment of inflammatory conditions such as systemic lupus erythematosus (SLE), systemic vasculitis, dermatomyositis, and inflammatory bowel disease. However, its use is often limited by myelotoxicity. Variants in the gene encoding thiopurine-S-methyltransferase (TPMT), an enzyme in the metabolic pathway of azathioprine, increase the risk for myelotoxicity1. We know little about the relationship between the genetically predicted expression of TPMT and side effects of azathioprine.

Objectives

To examine whether genetically predicted expression of TPMT in liver tissue is associated with azathioprine adverse effects.

Methods

We assembled a retrospective cohort of new users taking azathioprine for inflammatory conditions at a tertiary care center. We performed genotyping with Illumina Infinium Expanded Multi-Ethnic Genotyping Array plus custom content data, and we then used Michigan Imputation servers for genetic imputation and PrediXcan models trained with GTEx/Genotype-Tissue Expression Project version 8 data to impute TPMT expression in liver tissue. We prespecified nine groups of phecodes (comprised of ICD9 and ICD10 codes) corresponding to known adverse effects of azathioprine. We then tested the association between the predicted expression of TPMT and these adverse events; for outcomes significant in the Wilcoxon ranksum tests (p<0.05), each case was reviewed in clinical records for confirmation. Finally, we grouped the predicted expression of TPMT in liver tissue into tertiles and conducted logistic regressions to assess the associations between predicted expression and side effects. We conducted a sensitivity analysis restricted to patients with EHR-reported White race.

Results

The cohort included 1034 patients (Table 1). Phecodes for 3 side effects—leukopenia (n=29), skin cancer (n=13), and rash (n=52)—were identified as associated with predicted TPMT expression in liver tissue. Of these, cases of side effects attributed to azathioprine were validated by chart review: leukopenia (96.6%; n=28), skin cancer (92.3%; n=12), and rash (9.6%; n=5) and used for analysis. When assessed by tertile of predicted TPMT expression, patients in the highest tertile had lower odds of having leukopenia (OR=0.35, 95%CI: 0.12-0.98, p=0.045) and a trend towards higher odds for skin cancer, but the number of cases was small (OR=3.56, 95%CI: 0.73-17.27, p=0.115). Confirmed cases of rash attributed to azathioprine were too few for meaningful analysis. We found similar results when restricted to patients with reported White race.

Table 1.

Characteristics of patients by TPMT expression

Lowest TertileMiddle TertileHighest TertileN=345N=345N=344Female sex, n (%)228 (66.1)244 (70.7)238 (69.2)EHR-reported White race, n (%)306 (88.7)293 (84.9)290 (84.3)Age, median [IQR]42 [29-58]43 [30-55]46 [30-56]Indication, n (%)Systemic lupus erythematosus38 (11.0)42 (12.2)38 (11.0)Inflammatory bowel disease191 (55.3)185 (53.6)190 (55.2)Other connective tissue disorder/autoimmune92 (26.7)96 (27.8)100 (29.1)Other24 (7.0)22 (6.4)16 (4.7)Verified leukopenia attributed to azathioprine, n (%)14 (4.1)9 (2.6)5 (1.5)Verified skin cancer attributed to azathioprine, n (%)2 (0.6)3 (0.9)7 (2.0)Verified rash attributed to azathioprine, n (%)2 (0.6)3 (0.9)0 (0)

Conclusion

This analysis suggests that PrediXcan may be useful for examining the association between gene expression and side effects of medications. Moreover, this approach successfully identified leukopenia as a side effect associated with predicted TPMT expression.

Acknowledgements

None to declare.

Disclosure of Interests

None declared.

POS1444 FLT1 AND EPHB2 ARE NOVEL GENETIC MARKERS ASSOCIATED WITH PANCREATITIS IN PATIENTS TAKING AZATHIOPRINE FOR IMMUNE-MEDIATED CONDITIONS: INTEGRATING GENOME- AND TRANSCRIPTOME-WIDE ASSOCIATION STUDIES

Background

Azathioprine (AZA) is a thiopurine immunosuppressant medication used to treat a variety of immune-mediated diseases. Unfortunately, its use is limited by adverse effects. Pancreatitis, a potentially severe, life-threatening side effect is independent of dose and necessitates AZA discontinuation given the high risk of recurrent pancreatitis with continued use or re-challenge. The mechanisms driving pancreatitis are unclear. While classic thiopurine-induced acute pancreatitis (TIAP) has been associated with HLA haplotypes, most patients taking AZA and presenting with pancreatitis do not fulfill the stringent criteria for TIAP.

Objectives

To identify genetic risk factors for pancreatitis in patients taking azathioprine for immune-mediated conditions.

Methods

Using a biobank linked to electronic health records (EHR) from a tertiary center, we identified new users of AZA. Patients were excluded if the primary indication for AZA was organ transplant or if there was a history of pancreatitis prior to AZA use. The analysis was restricted to patients with EHR-reported race as White due to insufficient case counts for the non-White group. We then identified patients with amylase or lipase values that exceeded twice the upper limit of normal (“>2x ULN”) or with ICD-9/ICD-10 codes for acute pancreatitis. Each record was manually reviewed to confirm the timing of AZA use in relation to laboratory derangements or ICD coding, as well as to further classify patients into three increasingly strict, but not exclusive categories: 1) pancreatic injury (amylase or lipase >2x ULN); 2) acute pancreatitis1, or 3) TIAP2. We completed genotyping with Illumina Infinium Expanded Multi-Ethnic Genotyping Array plus custom content data, employed Michigan Imputation servers for genetic imputation, and used PrediXcan (GTEx v8) to impute gene expression. We then conducted genome-wide association and transcriptome-wide association studies (GWAS, TWAS). Acknowledging the relatively small overall cohort, and possible imbalance of cases vs controls, we used the Firth logistic regression method, which is a penalized likelihood-based method.

Results

We studied 2127 AZA users (35.4% male; mean 44.5+/-17.2 years). The median AZA dose was 100mg/day (IQR: 50-125mg/day). Rheumatologic conditions (56.9%) and inflammatory bowel disease (40.4%) comprised the most common primary indications for AZA. Pancreatic injury, pancreatitis, and TIAP were diagnosed in 42 (2.0%), 16 (0.8%), and 9 (0.4%) patients, respectively. GWAS identified several significantly associated genes, many with overlapping TWAS findings in the pancreas and liver (Figure 1). From these, the two protein-encoding genes Fms Related Receptor Tyrosine Kinase-1 (FLT1) and Ephrin type-B receptor-2 (EPHB2) overlapped in two or more pancreatitis phenotypes in the TWAS and GWAS, respectively. EPHB2 was associated with a 8.6-fold (P=1.84 x 10-8) and a 31.4-fold (P=2.87x 10-8) higher likelihood of pancreatic injury and TIAP, respectively.

Figure 1.

Conclusion

FLT1—a gene that encodes a receptor tyrosine kinase and is a member of the vascular endothelial growth factor receptor (VEGFR) family—and EPHB2—a gene that encodes a member of the Eph receptor family, which is the largest subgroup of the receptor tyrosine kinase family—are novel genetic markers associated with pancreatitis in patients taking AZA. VEGF can potentiate inflammation and the pancreas microenvironment is known to promote VEGF expression, which has been linked to pancreatic cancer development; anti-VEGF treatments have been investigated both for mitigating inflammation and also anti-pancreatic cancer treatment. Future studies validating our findings in AZA-induced pancreatitis are warranted.

References

[1]Crockett et al. Gastroenterology (2018). 154(4):1096-1101.

[2]Heap et al. Nature Genetics (2014). 46:1131-1134

Disclosure of Interests

Shailja Shah Consultant of: ad hoc consultant for Phathom pharmaceuticals, Tyler Reese: None declared, Jacy Zanussi: None declared, Alyson Dickson: None declared, Laura Daniel: None declared, Ran Tao: None declared, Tyne Miller-Fleming: None declared, Peter Straub: None declared, Adriana Hung: None declared, Puran Nepal: None declared, Wei-Qi Wei: None declared, Elizabeth Phillips: None declared, Nancy Cox: None declared, Charles M. Stein: None declared, QiPeng Feng: None declared, Cecilia P. Chung: None declared

Use of ring fixator in the management of degloving injuries of lower limb

High-velocity trauma causes degloving injuries of extremities. Management depends upon the viability of the degloved flap. The degloved area must be covered either with flaps or with split skin grafts. Various methods have been described to provide skin coverage. However, graft uptake depends upon the surgical expertise, graft quality, graft bed circulation and of course immobilization of the grafted area, especially across joints. We describe here a simple technique, which eventually helps graft bed preparation, eases application of graft tissue, facilitates graft care and allows passive mobilization of joints as well.

Bilateral Congenital Cataract Associated with Multiple Epiphyseal Dysplasia: A case Report

Cataract in children has varied etiology. It may be associated with systemic diseases including skeletal dysplasias. However cataract in Multiple Epiphyseal Dysplasia is a rare association. A child presented with bilateral dense posterior sub capsular cataract and multiple bony abnormalities. Clinical and radiographic findings suggested the disease to be Multiple Epiphyseal Dysplasia. The aim of presenting this case is to report a case of congenital cataract having a rare association with the Multipe Epiphyseal Dyspalsia. Key words: Congenital cataract; Multiple Epiphyseal Dysplasia; Skeletal dysplasia DOI: http://dx.doi.org/10.3126/jnps.v32i1.5434   J. Nepal Paediatr. Soc. Vol.32(1) 2012 71-72

Randomized controlled trial comparing above- and below-elbow plaster casts for distal forearm fractures in children

PURPOSE

Long arm cast is the method of immobilization after closed reduction of the fracture of the distal third of the forearm, although short arm cast has been used to immobilize the forearm by some orthopedic surgeons. We conducted this study to evaluate the rate of displacement, union time, complication, and cost of treatment between the above-elbow and below-elbow plaster cast groups.

METHODS

We designed a prospective randomized controlled trial to compare above- and below-elbow casts for patients of distal forearm fracture aged 4-12 years. One hundred and one patients were presented to our institution during the period from 1st June 2007 to 31st May 2008. Twelve patients were excluded from the study. Eighty-nine patients were randomized into two groups. Four patients were lost to follow up. Hence, 85 patients, 42 in the above-elbow group and 43 in the below-elbow group, were analyzed. Informed consent was obtained prior to participation in the trial. The parameters to be studied were defined before treatment and noted in the pilot-tested pro forma and follow up was done.

RESULTS

Among the 85 patients analyzed, randomization was successful. Pain and swelling on the next day and at one week following cast application was significantly higher (P = 0.000) in the above-elbow group. Three cases in the above-elbow group needed slitting of the plaster cast. Remanipulation was needed more often in the above-elbow group (9.5%). Although the cast index was not statistically significant (P = 0.054) between the groups, those who needed remanipulation had a larger cast index (0.80). The total cost of the treatment and the number of school days lost was significantly higher (P = 0.000) in the above-elbow group.

CONCLUSION

Below-elbow cast treatment was comparable in terms of redisplacement, union time, and movement of the wrist to the above-elbow treatment. The complications rate and total cost was higher in the above-elbow plaster group, which could be a cost benefit if a below-elbow cast is used.

Comparison of Ponseti and Kite's method of treatment for idiopathic clubfoot

BACKGROUND

The manipulation and corrective cast application for club foot was known to be done by Kite's method. The Kite's method of manipulation (center of rotation of malaligned foot and fulcrum on cuboid) was modified by Ponseti (fulcrum on head of talus). Recently, Ponseti's method has gained popularity and vastly improved results are reported. We report randomized controlled trial where manipulation of club foot was done by Ponseti's and Kite's method and correction evaluated by Pirani score to compare the outcome of treatment.

MATERIALS AND METHODS

Sixty feet in 38 patients, 22 with bilateral and 16 with unilateral clubfeet in children less than two years of age and without any prior manipulation or surgical treatment were randomly allocated to the Ponseti (30 feet) and Kite (30 feet) methods of manipulation. This process resulted in the right and left feet of the same patient in 12 bilateral cases being compared with one another (Paired analysis). In the remaining 10 bilateral cases, four patients had both feet treated by Ponseti and six had both feet treated by Kite (unpaired analysis). Finally, in 16 unilateral cases, 10 feet were allocated to the Ponseti and six to Kite methods of manipulation (unpaired analysis). Feet were followed up weekly for 10 weeks for change of cast and recording of hindfoot, midfoot and total Pirani scores. Correction was measured as a difference between hindfoot, mid foot and total Pirani scores weekly from weeks 1 to 10 and corresponding baseline scores. Absolute correction and rate of correction in (i) bilateral clubfeet treated by Ponseti's method on one side and Kite's method on the other side in the same patient were compared using paired Student's t test and (ii) patients with unilateral clubfoot (where either of the methods was used) or those with bilateral clubfoot (where both feet treated by either of the two methods on both the sides) were compared using difference between means (mean correction by Ponseti minus mean correction by Kite) for magnitude of difference and unpaired Student's t test (if data was normally distributed) or Mann Whitney U statistics (otherwise) for significance of difference.

RESULTS

In 12 bilateral clubfeet, where one foot received Kite's method and the other Ponseti's manipulation, feet treated by Ponseti's technique showed faster rates of decrease in Pirani score (improvement) as compared to feet treated by Kite's method with the mean of difference between baseline and follow up scores showing significantly greater (P<0.05) difference from zero from fourth week onwards to up to 10 weeks. In unpaired analysis, both for unilateral or bilateral clubfeet, regardless of side, mean Pirani scores in Ponseti feet improved much faster than Kite feet but the difference achieved statistical significance only at the 10(th) week from the start of treatment.

CONCLUSIONS

Hind foot, midfoot and total Pirani scores reduce much faster with Ponseti than the Kite's method of manipulation of clubfoot. In paired analysis the difference becomes statistically significant at fourth week and in unpaired analysis at 10(th) week from the start of treatment.

Tumor de células gigantes da extremidade distal do fêmur: um desafio de tratamento

Apresentamos aqui um caso de tumor de células gigantes na extremidade distal do fêmur direito tratado com ressecção da massa tumoral em bloco com remoção aguda da extremidade proximal e distal e fixado com hastes longas em K atravessando o joelho, do fêmur à tíbia. Após a consolidação / união completa das extremidades, foi feita a remoção da haste em K, seguida pela corticotomia juntamente com a osteogênese da distração com o auxílio do anel fixador de Ilizarov. O comprimento foi alcançado com este processo. O resultado final foi muito bom neste caso. Revisamos as opções de tratamento para tumor maligno de células gigantes na extremidade distal do fêmur e as dificuldades de tratá-lo.

Complex elbow dislocation with ipsilateral segmental fracture of radius and ulna in a young boy: a complex injury with multiple fractures

Complex elbow dislocation1 (fracture of lateral condyle and avulsion fracture of medial epicondyle) with ipsilateral segmental fracture of radius and ulna without distal neurovascular deficit following machinery rolling belt injury in a 14 years boy presenting to emergency room of BP Koirala Institute of Health Sciences, is reported due to its complex nature of injury and good outcome after adequate follow up. The literature is reviewed for complex elbow dislocation to show its rarity.

Polyarticular tuberculosis in a young boy: a rare presentation

Polyarticular tuberculosis involving bilateral hip and bilateral knee joints without obvious pulmonary or disseminated form of tuberculosis in a young boy is presented along with literature review.

Giant malignant nerve sheath tumor of lumbosacral plexus with intraspinal extension in a child with neurofibromatosis type 1

Malignant peripheral nerve sheath tumors (MPNSTs) are the leading cause of death in young adults and are one of the most frequent non-rhabdomyosarcomatous soft tissue tumors in pediatric age. These tumors usually occur in young adults from a previously recognized neurofibroma, neurofibromatosis type 1 (NF1), with a noted change in size and pain. This child reached the age of 10 without the presence of the more commonly seen manifestations of NF1. Pseudoarthrosis in children has a high rate of association with NF1, and in this case diagnosis of NF1 was supported by development of MPNST in a pre-existing plexiform neurofibroma.

Osteosarcoma in pregnancy

Osteosarcoma in pregnant women is rare. Delay in diagnosis may be due to lack of any signs or symptoms during gestation, clinical misdiagnoses, religious attitude and refusal of the patients. Most cases soft-tissue and bone tumors during pregnancy can be managed successfully with surgery during gestation. Therapies with fetal toxicity were more likely to be deferred to postpartum period. This case is rare and liable to be missed, hence is reported.

Osteosarcoma in Pregnancy

Osteosarcoma in pregnant women is rare. Delay in diagnosis may be due to lack of any signs or symptomsduring gestation, clinical misdiagnoses, religious attitude and refusal of the patients. Most cases soft-tissueand bone tumors during pregnancy can be managed successfully with surgery during gestation. Therapieswith fetal toxicity were more likely to be deferred to postpartum period. This case is rare and liable to bemissed, hence is reported.