Clinical Focus

  • Pediatric Hepatology
  • Pediatric Transplant Hepatology
  • Pediatric Gastroenterology

Academic Appointments

Professional Education

  • Board Certification: American Board of Pediatrics, Transplant Hepatology (2020)
  • Medical Education: New York Medical College Registrar (2012) NY
  • Fellowship: Children's Hospital Los Angeles Pediatric Transplant Hepatology (2019) CA
  • Fellowship: Children's Hospital Los Angeles Pediatric Gastroenterology (2018) CA
  • Board Certification: American Board of Pediatrics, Pediatrics (2015)
  • Residency: Baylor College of Medicine Pediatric Residency (2015) TX

All Publications

  • Profound neonatal lactic acidosis and renal tubulopathy in a patient with glycogen storage disease type IXɑ2 secondary to a de novo pathogenic variant in PHKA2. Molecular genetics and metabolism reports Morales, J. A., Tise, C. G., Narang, A., Grimm, P. C., Enns, G. M., Lee, C. U. 2021; 27: 100765


    The phenotype of individuals with glycogen storage disease (GSD) IX appears to be highly variable, even within subtypes. Features include short stature, fasting hypoglycemia with ketosis, hepatomegaly, and transaminitis. GSD IXɑ2 is caused by hemizygous pathogenic variants in PHKA2, and results in deficiency of the phosphorylase kinase enzyme, particularly in the liver. Like other GSDs, GSD IXɑ2 can present with hypoglycemia and post-prandial lactic acidosis, but has never been reported in a newborn, nor with lactic acidosis as the presenting feature. Here we describe the clinical presentation and course of a newborn boy with profound neonatal lactic and metabolic acidosis, renal tubulopathy, and sensorineural hearing loss (SNHL) diagnosed with GSD IXɑ2 through exome sequencing. Review of the literature suggests this case represents an atypical and severe presentation of GSD IXɑ2 and proposes expansion of the phenotype to include neonatal lactic acidosis and renal tubulopathy.

    View details for DOI 10.1016/j.ymgmr.2021.100765

    View details for PubMedID 34277355

    View details for PubMedCentralID PMC8261893

  • Profound neonatal lactic acidosis and renal tubulopathy in a patient with glycogen storage disease type IXa2 secondary to a de novo pathogenic variant in PHKA2 MOLECULAR GENETICS AND METABOLISM REPORTS Morales, J., Tise, C. G., Narang, A., Grimm, P. C., Enns, G. M., Lee, C. U. 2021; 27
  • Severe Late-Onset Acute Cellular Rejection in a Pediatric Patient With Isolated Small Intestinal Transplant Rescued With Aggressive Immunosuppressive Approach: A Case Report. Transplantation proceedings Narang, A., Xi, D., Mitsinikos, T., Genyk, Y., Thomas, D., Kohli, R., Lin, C. H., Soufi, N., Warren, M., Merritt, R., Yanni, G. 2019; 51 (9): 3181-3185


    Small intestinal transplantation is performed for patients with intestinal failure who failed other surgical and medical treatment. It carries notable risks, including, but not limited to, acute and chronic cellular rejection and graft malfunction. Late severe acute intestinal allograft rejection is associated with increased risk of morbidity and mortality and, in the majority of cases, ends with total enterectomy. It usually results from subtherapeutic immunosuppression or nonadherence to medical treatment. We present the case of a 20-year-old patient who underwent isolated small bowel transplant for total intestinal Hirschsprung disease at age 7. Due to medication nonadherence, she developed severe late-onset acute cellular rejection manifested by high, bloody ostomy output and weight loss. Ileoscopy showed complete loss of normal intestinal anatomic landmarks and ulcerated mucosa. Graft biopsies showed ulceration and granulation tissue with severe architectural distortion consistent with severe intestinal graft rejection. She initially received intravenous corticosteroids and increased tacrolimus dose without significant improvement. Her immunosuppression was escalated to include infliximab and finally antithymocyte globulin. Graft enterectomy was considered repeatedly; however, clinical improvement was noted eventually with evidence of histologic improvement and salvage of the graft. The aggressive antirejection treatment was complicated by development of post-transplant lymphoproliferative disorder that resolved with reducing immunosuppression. Her graft function is currently maintained on tacrolimus, oral prednisone, and a periodic infliximab infusion. We conclude that a prompt and aggressive immunosuppressive approach significantly increases the chance of rescuing small bowel transplant rejection.

    View details for DOI 10.1016/j.transproceed.2019.08.012

    View details for PubMedID 31711586

  • A 10-Year united network for organ sharing review of mortality and risk factors in young children awaiting liver transplantation. Liver transplantation : official publication of the American Association for the Study of Liver Diseases and the International Liver Transplantation Society Leung, D. H., Narang, A., Minard, C. G., Hiremath, G., Goss, J. A., Shepherd, R. 2016; 22 (11): 1584-1592


    Young children < 2 years of age with chronic end-stage liver disease (YC2) are a uniquely vulnerable group listed for liver transplantation, characterized by a predominance of biliary atresia (BA). To investigate wait-list mortality, associated risk factors, and outcomes of YC2, we evaluated United Network for Organ Sharing registry data from April 2003 to March 2013 for YC2 listed for deceased donor transplant (BA = 994; other chronic liver disease [CLD] = 221). Overall, wait-list mortality among YC2 was 12.4% and posttransplant mortality was 8%, accounting for an overall postlisting mortality of 19.6%. YC2 demonstrated 12.2%, 18.7%, and 20.6% wait-list mortality by 90, 180, and 270 days, respectively. YC2 with CLD demonstrated significantly higher wait-list mortality compared with BA among YC2 (23.9% versus 9.8%; P < 0.05). Multivariate analyses revealed that listing Pediatric End-Stage Liver Disease [PELD] > 21 (hazard ratio [HR], 3.2; 95% confidence interval [CI], 1.6-6.5), lack of exception (HR, 5.8; 95% CI, 2.8-11.8), listing height < 60.6 cm (HR, 2.1; 95% CI, 1.4-3.1), listing weight  > 10 kg (HR, 3.8; 95% CI, 1.5-9.2), and initial creatinine > 0.5 (HR, 6.8; 95% CI, 3.4-13.5) were independent risk factors for YC2 wait-list mortality (P < 0.005 for all). Adjusting for all variables, the risk of death among CLD patients was 2 (95% CI, 1.3-3.1) times greater than patients with BA + surgery (presumed Kasai). Furthermore, the risk of death in BA without surgery was 1.9 (95% CI, 1‐3.4) times greater than BA with presumed Kasai. Our data highlight unacceptably high wait-list and early post-liver transplant mortality in YC2 not predicted by PELD and suggest key risk factors deserving of further study in this age group. Liver Transplantation 22 1584-1592 2016 AASLD.

    View details for DOI 10.1002/lt.24605

    View details for PubMedID 27541809

    View details for PubMedCentralID PMC5083224