Congenital amegakaryocytic thrombocytopenia with severe
neurological findings
O
¨
zcan Bo ¨r
a
, Ayse B. Turhan
a
and Coskun Yarar
b
Congenital amegakaryocytic thrombocytopenia (CAMT) is a
rare autosomal recessive disorder characterized by
thrombocytopenia from failure of megakaryopoiesis. The
genetic background of CAMT is mutations in the
myeloproliferative ligand gene encoding the
thrombopoietin receptor. In our patient with CAMT, we
identified homozygous missense mutations [c.407C>T
(p.P136L)]. The association of CAMT and central nervous
system (CNS) abnormalities is uncommon. Here we present
a case in which CAMT appears linked to CNS abnormalities
(encephalomalacia, global atrophy) and developmental
delay related with intrauterine intracranial hemorrhage.
Blood Coagul Fibrinolysis 26:000–000 Copyright ß 2016
Wolters Kluwer Health, Inc. All rights reserved.
Blood Coagulation and Fibrinolysis 2016, 27:00–00
Keywords: amegakaryocyte, central nervous system abnormalities,
mutation, newborn, thrombocytopenia
a
Division of Pediatric Hematology and Oncology and
b
Division of Pediatric
Neurology, Department of Pediatrics, University of Eskis ¸ehir Osmangazi, School
of Medicine, Eskisehir, Turkey
Correspondence to Ayse B. Turhan, Division of Pediatric Hematology and
Oncology, Department of Pediatrics, Eskisehir Osmangazi University Faculty of
Medicine, Eskisehir 26480, Turkey.
Tel: +0090 530 527 19 þ97; fax: +0090 216 651 98 58;
e-mail: aysebturhan@hotmail.com
Received 2 July 2015 Revised 4 November 2015
Accepted 7 November 2015
Introduction
Congenital amegakaryocytic thrombocytopenia (CAMT)
is a rare disorder characterized by thrombocytopenia and
absence or decline in the number of megakaryocytic
precursors in the bone marrow. In most of the cases
the disease is caused by homozygous or compound
heterozygous mutations in the gene myeloproliferative
ligand (MPL) encoding the receptor for the hematopoie-
tic growth factor thrombopoietin [1–3].
The association of CAMT and central nervous system
(CNS) abnormalities is uncommon. c-Mpl is expressed
not only in platelets, but also in hematopoietic precursor
cells, brain and liver among other organs. c-Mpl mutation
may also affect brain development during infancy,
explaining the association between thrombocytopenia
and cerebral malformations in some patients with CAMT
[4,5]. The most frequently described CNS malformations
in patients with CAMT are intra or extra utero intracra-
nial hemorrhages reported in only up to 25% of patients
[4]. The association between CAMT and other types
of CNS malformations is even less common. Here we
present a case where CAMT appears linked to CNS
abnormalities (encephalomalacia, global atrophy) and
developmental delay.
Brief report
Our patient was referred to our hospital with the com-
plaint of petechiae and thrombocytopenia (12 000/mm
3
)
at the 7th day of life. Physical examination, hemoglobin
and white blood cell count and mean corpuscular eryth-
rocyte volume were normal. When viewed on peripheral
blood smears, platelets were of normal size and granu-
larity. Over the first 3 days the blood culture was sterile
and antibiotic treatment was stopped. A urine culture
for cytomegalovirus was negative, as were rapid diagnos-
tic tests for herpes simplex and titers for toxoplasmosis,
cytomegalovirus, rubella and herpes. An echocardiogram
was normal, as was a head ultrasound study. Almost daily
platelet transfusions were required to maintain platelet
counts higher than 50 000/mm
3
in the neonatal period.
Bone marrow aspirate has been performed at the 19th day
of life, and revealed as apparently normocellular bone
marrow morphology with decreased number of megakary-
ocytes with normal nuclear lobulation and cytoplasmic
granularity.
The full spectrum of erythroid and myeloid maturation
was present with no dyspoietic features in addition to
no evidence of malignancy, leukemia, lymphoma and
metastasis. In neonatal period, cranial magnetic reson-
ance imaging revealed chronic bleeding areas (Fig. 1).
There were no responses to either recurrent intravenous
immunoglobulin or steroid treatment. Beyond 8 month
of age, platelet counts were maintained higher than
10 000–20 000/mm
3
with transfusions twice a week.
Genetic analysis revealed as CAMT, with positive
homozygous mutation of c-Mpl [c.407C>T (p.P136L)].
During the follow-up period, progressive and severe
neurodevelopmental delay has been seen. On physical
examination, he had increased muscle tone, especially in
the lower extremities, and flexion deformities have been
noted on the right hand. Cranial magnetic resonance
imaging revealed encephalomalacia and global atrophy
(Fig. 2). Neurological findings of our patients with spastic
hemiplegic cerebral palsy were called. Neurological
course and findings of our patient might be related with
Case report 1
0957-5235 Copyright ß 2016 Wolters Kluwer Health, Inc. All rights reserved. DOI:10.1097/MBC.0000000000000508
Copyright © 2016 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.