Medical Student Research Fellowship for Summer 2007

Mentor: Gregory L. Jackson, M.D., William D. Engle, M.D., Dorothy M. Sendelbach, M.D.
Department: Pediatrics
Room number: Parkland Newborn Nursery
Mail Code: 9063
Phone number: 214-590-8034
E-mail: Greg.jackson@utsouthwestern.eduProject title: Incidence of Hematologic Disorders in Predominantly Hispanic Neonates with Down Syndrome
Human subjects IRB approved project number (where applicable): Pending
Animal subjects IRB approved project number (where applicable):

Project Type (patient-based research, animal-based research, or basic research; this characterization is only to permit a general classification for grouping similar types of projects) Patient-based
Brief Description of Project:
Transient myeloproliferative disorder (TMD) - also referred to as "transient leukemia" - is a phenomenon seen in only Down Syndrome or Trisomy 21 mosaicism. It consists of immature white blood cells (progenitors such as mywloblastsblasts, metamyelocytes, and prometamyelocytes) in the peripheral blood smear of neonates. Most often, TMD is discovered incidentally if a complete blood count with differential (CBC) is performed on these patients. The incidence is unknown, since studies of individual populations have not been performed. However, most articles and texts refer to Doyle and Zipursky , stating that the incidence could be approximately 10% of babies with Down Syndrome. Additionally, thrombocytopenia and polycythemia also occur in higher frequency with these neonates.
Since 2001, American Academy of Pediatrics guidelines have recommended a routine CBC in the neonatal period for neonates suspected of having Down Syndrome. However, the Newborn Nursery at Parkland Memorial Hospital (NBN) has been performing CBCs on these patients for at least 10 years, with a population base of over 150,000 neonates during that time. Our impression has been that, in our population of predominantly Hispanic neonates, the incidence of TMD is much lower than 10%, approaching 1% or less. We are also not aware of our incidence of thrombocytopenia and polycythemia in the neonatal period. However, we have not reviewed this information.
It would be a useful addition to the literature to review our experience of hematologic abnormalities in babies with suspected Down Syndrome. We propose a retrospective review of charts for babies identified in our NBN quality assurance database as being suspected as having Down Syndrome. In addition, we will ask to review the Medical Records database at Parkland Memorial Hospital to cross-reference the ICD-9 code for this chromosomal abnormality (code 758.0 is "Down Syndrome;" also, code 758 is "chromosomal anomalies not otherwise specified"). This will capture those neonates who were admitted directly to the Neonatal Intensive Care Unit (those that are not a part of the NBN database).

With time permitting, we also propose to cross-reference these neonate's records with those at the Genetics Clinics at Children's Medical Center (CMC), since all neonates suspected of having Down Syndrome are referred there for follow-up at 3 months of age. Information from CMC will include CBC results and hematologic outcomes (e.g., development of leukemia).
Previous Research Activities or Publications with Medical Students:
Elaine Duryea: Summer 2005 and Summer 2006
Susanna Lai: Summer 2005 and Summer 2006
Holly Barko: Doris Duke Fellow 2005-2006

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