von Hippel-Lindau (VHL) protein is the principal negative regulator of hypoxia sensing mediated by transcription factors. Mutations in exon 3 of the VHL gene lead to Chuvash (VHL(R200W)) and Croatian (VHL(H191D)) polycythemias. Here, we describe an infant of Bangladesh ethnicity with a novel homozygous VHL(D126N) mutation with congenital polycythemia and dramatically elevated erythropoietin (EPO) levels, who developed severe fatal pulmonary hypertension. In contrast to Chuvash polycythemia, erythroid progenitors (BFU-Es) did not reveal a marked EPO hypersensitivity. Further, NF-E2 and RUNX1 transcripts that correlate with BFU-Es EPO hypersensitivity in polycythemic mutations were not elevated.
Alpha thalassemia due to nondeletional mutations usually leads to more severe disease than that caused by deletional mutations. Devastating outcomes such as hydrops fetalis can occur with two nondeletional mutations, therefore warranting DNA-based workup for suspected carriers with subtle hematological abnormalities for family counseling purposes. We describe three cases with hemoglobin (Hb) Adana, a nondeletional alpha chain mutation, compounded with an alpha globin gene deletion resulting in thalassemia intermedia. We review the literature, draw genotype-phenotype correlations from published cases of Hb Adana, and propose that this correlation can be used by clinicians to help direct diagnostic studies and urge hematologists to thoroughly workup high-risk patients.
Pediatricians provide a medical home for children with congenital syndromes who often need complex multidisciplinary care. There are some syndromes associated with thrombocytopenia, inherited platelet disorders, factor deficiencies, connective tissue disorders, and vascular abnormalities, which pose a real risk of bleeding in affected children associated with trauma or surgeries. The risk of bleeding is not often an obvious feature of the syndrome and not well documented in the literature. This makes it especially hard for pediatricians who may care for a handful of children with these rare congenital syndromes in their lifetime. This review provides an overview of the etiology of bleeding in the different congenital syndromes along with a concise review of the hematologic and nonhematologic clinical manifestations. It also highlights the need and timing of diagnostic evaluation to uncover the bleeding risk in these syndromes emphasizing a primary care approach.
The goal of our project is to develop a unique ligand-conjugated nanoparticle (NP) therapy against childhood acute lymphoblastic leukemia (ALL). LLP2A, discovered by Dr. Kit Lam, is a high-affinity and high-specificity peptidomimetic ligand against an activated α4β1 integrin. Our study using 11 fresh primary ALL samples (10 precursor B ALL and 1 T ALL) showed that childhood ALL cells expressed activated α4β1 integrin and bound to LLP2A. Normal hematopoietic cells such as activated lymphocytes and monocytes expressed activated α4β1 integrin; however, normal hematopoietic stem cells showed low expression of α4β1 integrin. Therefore, we believe that LLP2A can be used as a targeted therapy for childhood ALL. The Lam lab has developed novel telodendrimer-based nanoparticles (NPs) which can carry drugs efficiently. We have also developed a human leukemia mouse model using immunodeficient NOD/SCID/IL2Rγ null mice engrafted with primary childhood ALL cells from our patients. LLP2A-conjugated NPs will be evaluated both in vitro and in vivo using primary leukemia cells and this mouse model. NPs will be loaded first with DiD near infra-red dye, and then with the chemotherapeutic agents daunorubicin or vincristine. Both drugs are mainstays of current chemotherapy for childhood ALL. Targeting properties of LLP2A-conjugated NPs will be evaluated by fluorescent microscopy, flow cytometry, MTS assay, and mouse survival after treatment. We expect that LLP2A-conjugated NPs will be preferentially delivered and endocytosed to leukemia cells as an effective targeted therapy.
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