Li et al. BMC Medical Genetics(2020) 21:224
https://doi.org/10.1186/s12881-020-01163-2

CASE REPORTOpen AccessCongenital thrombocytopenia associatedwith GNE mutations in twin sisters: a casereport and literature review
Li Xin1,2, Ying Li1, Min Lei1, Jing Tian1, Zuocheng Yang1, Shoujin Kuang1, Yanjuan Tan1 and Tao Bo1*

Abstract
Background: Neonatal thrombocytopenia is common in preterm and term neonates admitted to neonatal
intensive care units. The etiology behind neonatal thrombocytopenia is complex. Inherited thrombocytopenia israre and usually results from genetic mutations.
Case presentation: Here we report a case of twins with severe inherited thrombocytopenia presented in the
neonatal period who were shown to be compound heterozygotes for 2 UDP-N-acetylglucosamine 2-epimerase(GNE) gene mutations, c.1351C > T and c.1330G > T, of which c.1330G > T is a novel mutation.
Conclusion: These two GNE mutations may help in the diagnosis and management of thrombocytopenia
diagnosed in neonates.
Keywords: Congenital thrombocytopenia, UDP-N-acetyl-glucosamine 2-epimerase/N-acetylmannosamine kinase(GNE), Sialic acid, Neonates, Twins

Background
Thrombocytopenia is defined as a platelet count < 150 ×
109/L and is the most frequent hematological disorderobserved in neonates admitted to the neonatal intensive
care unit (NICU). This disorder has an incidence between 18 and 35% [1] It is known that reduced production of platelets induces thrombocytopenia, whose
heritable forms are frequently caused by genes that regulate megakaryocytic differentiation and/or platelet production [2] With the development of diagnostic
methods, neonatal thrombocytopenia, especially the congenital type, was linked to genetic mutations.
UDP-N-acetyl-glucosamine 2-epimerase/N-acetylmannosamine kinase (GNE), a key enzyme of sialic acid biosynthesis, initiates and regulates the biosynthesis of Nacetylneuraminic acid [3] Mutations in GNE have been
* Correspondence: boily@yeah.net
1
Department of Pediatrics, The Third Xiangya Hospital, Central South
University, Tongzipo Road NO.138, Changsha 410013, China
Full list of author information is available at the end of the article

identified in both hereditary inclusion body myopathy andNonaka myopathy, which is also termed as distal myopathy
with rimmed vacuoles (DMRV; MIM#605820) [2, 4] In recent years, the relationship between GNE mutations andcongenital thrombocytopenia has been reported [3, 5–8]
Here, we report a case of twin sisters who were shown tohave novel combined heterozygous GNE mutations and diagnosed with refractory thrombocytopenia.

Case report
A 22-day-old female newborn exhibited a platelet countof 1 × 109/L and showed detectable traces of blood in
her stools. At the same time, her twin sister also had aplatelet count of 6 × 109/L. The twins were born 37 3/7
weeks of gestational through cesarean section to amother who denies unfavorable obstetric or medical histories. Moreover, there was no history ofthrombocytopenia in the family. When the newborns
were admitted to the NICU, vital signs and physical examinations appeared normal. Blood laboratory studies© The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License,
which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give
appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate ifchanges were made. The images or other third party material in this article are included in the article's Creative Commonslicence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commonslicence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain
permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to thedata made available in this article, unless otherwise stated in a credit line to the data.

Li et al. BMC Medical Genetics(2020) 21:224

showed severe thrombocytopenia and mild anemia in
the twins. The size of their peripheral blood platelets
was shown to range from normal to large and theirmean platelet volume was 10.6–13.2 fl (reference range:
6.5-12 fl). Routine urine, stool, liver function and renal
function tests all appeared as normal. TORCH- andplatelet-associated antibodies were negative. Megakaryocytes in the bone marrow showed normal morphology,
but their maturation was hindered. Whole exon sequencing (WES) analysis revealed novel compound heterozygous mutations in exon 6 of the GNE gene (Fig. 1a),including c.1351C > T, (p. Arg451*) and c.1330G > T, (p.
Asp444Tyr) (Fig. 1b, c). No other gene mutations related
to thrombocytopenia were identified. A genogram directly confirmed that the twins were compound heterozygotes for these mutations (Fig. 1d). In the Genome
Aggregation Database (gnomAD), the occurrence frequency of the two mutations was found to be 4/251452(c.1351C > T) and 1/251452 (c.1330G > T). The c.
1330G > T was found to be a novel mutation. Despite
being reported in HGMD as described by Tomimitsu [9]et al and Mori-Yoshimura [10] et al, c.1351C > T mutations associated with thrombocytopenia are first reported here. The p. Arg451* based reference sequence
NM_005476.6 is a non-sense mutation. Furthermore,mutation pathogenicity prediction software, including
Sorting Intolerant From Tolerant (SIFT), Polyphen2,
LRT, MutationTaster, PredictSNP (https://loschmidt.
chemi.muni.cz/predictsnp/) and FATHMM, predictedthat the c.1330G > T mutation was harmful and destabilizing. Homology modeling was performed for the wildtype or mutant proteins using the SWISS-MODEL server (https://swissmodel.expasy.org/). As shown in Fig.
1e, c.1351C > T results in the deletion of 8 amino acids
starting at position 451, whereas c.1330G > T results in
an Asp to Tyr mutation at position 444. Therefore, thetwins were diagnosed with congenital thrombocytopenia
associated with GNE mutations.
The twins received platelet and intravenous immunoglobulin (IVIG) transfusions soon after admission to the
NICU given their severe thrombocytopenia, but theirbaseline platelet counts remained as less than 10 × 109/L.
After a 3-month follow-up, the twins did not show
bleeding or signs of muscle wasting.

Discussion and conclusion
The human GNE gene (NM_001128227.2), localized on
chromosome 9p13.3, consists of 14 exons and encodes
724 amino acids [3, 5, 6, 11] The protein encoded by thisgene is a bifunctional enzyme that initiates and regulates
the biosynthesis of N-acetylneuraminic acid (NeuAc),
which is a precursor of sialic acid [12].
Mutations in the GNE gene decreases its enzymatic activity and affects the two initial steps in sialic acid

Page 2 of 4

biosynthesis. As a result, sialic acid production decreases
and consequently, sialylation, or the incorporation of sialic acid to glycoproteins and glycolipids, also decreases[13] Hyposialylation was previously identified in mousemodels of GNE myopathy [14] More than 10 GNE genemutations have been reported in human DMRV. However, the exact mechanisms behind GNE defects leading
to DMRV are still not fully understood.
As a major determinant of cell surface sialylation inhuman hematopoietic cell lines and a critical regulatorof cell surface adhesion molecules [15], GNE is also
expressed in bone marrow. Sialic acid is known to playsignificant roles in platelet functions and is located in
the platelet membrane, forming during glycosylation.
Several groups have shown that platelets deficient in sialylation are removed from circulation, resulting in shortened circulation lifetimes and thrombocytopenia [16]In 2014, two families diagnosed with DMRV associatedwith thrombocytopenia were reported. Izumi et al [2] reported that two adult siblings diagnosed with DMRV andthrombocytopenia harbored two compound heterozygous
GNE mutations, p.V603L and p.G739S. Zhen et al [17] reported that two adult siblings in a DMRV family exhibited
thrombocytopenia and showed compound heterozygous
GNE mutations including a missense mutation c.649 T >C, (p.Y217H) and a frameshift mutation c.1543–1544 delGA, (p.D515Qfs*2). These patients showed mild-tomoderate thrombocytopenia and no obvious bleeding.
In 2018, it was reported that GNE mutations cause
thrombocytopenia without associated myopathy. Futterer
et al [8] reported that two cousins in a consanguineousfamily manifested moderate to severe bleeding associatedwith severe thrombocytopenia and required regular platelet transfusions. In addition, homozygous mutations c.
1246 G > A, (p. G416r) in the GNE gene were detected.
Revel-Vilk et al [18] summarized nine patients from threefamilies all exhibiting thrombocytopenia and mild to moderate hemorrhagic tendencies. All of these individuals
contained compound homozygous or heterozygous mutations in GNE, of which eight of the nine patients inshowed no evidence of myopathy and one patient withneuromuscular symptoms showed a muscle biopsy inconsistent with GNE myopathy.
In the case of the twins described here, refractory severe
thrombocytopenia was identified in the neonatal period
and two novel compound heterozygous GNE mutations,p.Arg451* and p.Asp444Tyr, were detected using wholeexome sequencing. Compared with other reports, thesetwins are some of the youngest reported and their baseline
platelet counts were of the lowest values when they werediagnosed. Consistent with other reports [17, 19, 20], mutations in GNE associated with thrombocytopenia were
within the N-acetylmannosamine (ManNAc) kinase domains of the GNE protein. Thus, this domain may be anLi et al. BMC Medical Genetics(2020) 21:224

Page 3 of 4

Fig. 1 Sequencing and a genogram of the Trio. a:Schematic diagram of GNE exons. Mutation positions were labeled with black lines. b: Thec.1351C > T mutation. This mutation is a non-sense mutation, where arginine (Arg) mutates to a termination codon, which is inherited from themother. c: The c.1330G > T mutation. This mutation is inherited from the father and is a missense mutation, resulting when aspartic acid (Asp)mutates to tyrosine (Tyr). d: Parents are carriers of each mutation and show no phenotypes. The twins simultaneously inherited two mutations
from their parents and presented with refractory thrombocytopenia several days after birth. e: 3D homology model changes induced by the c.
1330G > T and c.1351C > T mutations

interesting site for further investigation related to congenital thrombocytopenia associated with GNE mutations.
In summary, in this report, we describe twins with twonovel compound heterozygous GNE mutations, including p.Arg451* and p.Asp444Tyr, who manifested only
severe thrombocytopenia without myopathy. Yet the roleof GNE protein in the synthesis and functions of platelet
requires further investigation.

Abbreviations
GNE: UDP-N-acetyl-glucosamine 2-epimerase/N-acetylmannosamine kinase;
NeuAc: N-acetylneuraminic acid; ExAC: Exome Aggregation Consortium;
gnomAD: Genome Aggregation Database; SIFT: Sorting Intolerant From
Tolerant
Acknowledgments
We first thank the patients and their parents. We are also grateful to CIPHER
GENE company, providing us the whole-exome sequencing and data
analysis.

Li et al. BMC Medical Genetics(2020) 21:224

Authors’ contributions
YL, ML, JT, ZCY, SJK, YJT participated in the management of the patients,
acquired the clinical data, and prepared the samples from the family
members. XL, TB drafted the initial manuscript, and reviewed and revised themanuscript. All authors approved the final manuscript as submitted andagree to be accountable for all aspects of the work.
Funding
No funding was received.
Availability of data and materials
The datasets analysed during the current study are available in the 360
medical repository(https://yunpan.360.cn/surl_yPErJZuASnH).
NM_005476.6(genebank https://www.ncbi.nlm.nih.gov/nuccore/NM_005476.6).
NM_001128227.2(genebank https://www.ncbi.nlm.nih.gov/nuccore/NM_
001128227.2).
Ethics approval and consent to participate
This study was approved by the Ethics Committee of the 3rd Xiangya
Hospital, Central South University. Written informed consent was obtained
from the parents of the patient.
Consent for publication
Written informed consent was obtained from the parents for publication ofthis case report.
Competing interests
The authors have no conflicts of interest to disclose.
Author details
1
Department of Pediatrics, The Third Xiangya Hospital, Central South
University, Tongzipo Road NO.138, Changsha 410013, China. 2Chengdu
Women’s and Children’s Central Hospital, School of Medicine, University ofElectronic Science and Technology of China, Chengdu 611731, Sichuan,
China.
Received: 5 September 2019 Accepted: 4 November 2020

References
1. Cremer M, Sallmon H, Kling PJ, Buhrer C, Dame C. Thrombocytopenia andplatelet transfusion in the neonate. Semin Fetal Neonatal Med. 2016;21(1):
10–8.
2. Izumi R, Niihori T, Suzuki N, Sasahara Y, Rikiishi T, Nishiyama A, et al. GNE
myopathy associated with congenital thrombocytopenia: a report of two
siblings. Neuromuscul Disord. 2014;24(12):1068–72.
3. Alrohaif H, Pogoryelova O, Al-Ajmi A, Aljeryan LA, Alrashidi NH, Alefasi SA,
et al. GNE myopathy in the bedouin population of Kuwait: genetics,
prevalence, and clinical description. Muscle Nerve. 2018;58(5):700–7.
4. Carrillo N, Malicdan MC, Huizing M. GNE myopathy: etiology, diagnosis, andtherapeutic challenges. Neurotherapeutics. 2018;15(4):900–14.
5. Barel O, Kogan E, Sadeh M, Kol N, Nayschool O, Benninger F. Abdominal
muscle weakness as a presenting symptom in GNE myopathy. J Clin
Neurosci. 2019;59:316–17.
6. Bhattacharya S, Khadilkar SV, Nalini A, Ganapathy A, Mannan AU, MajumderPP, et al. Mutation Spectrum of GNE myopathy in the Indian sub-continent.
J Neuromuscul Dis. 2018;5(1):85–92.
7. Chen Y, Xi J, Zhu W, Lin J, Luo S, Yue D, et al. GNE myopathy in Chinese
population: hotspot and novel mutations. J Hum Genet. 2019;64(1):11–6.
8. Futterer J, Dalby A, Lowe GC, Johnson B, Simpson MA, Motwani J, et al.
Mutation in GNE is associated with severe congenital thrombocytopenia.
Blood. 2018;132(17):1855–8.
9. Tomimitsu H, Shimizu J, Ishikawa K, Ohkoshi N, Kanazawa I, Mizusawa H.
Distal myopathy with rimmed vacuoles (DMRV): new GNE mutations andsplice variant. Neurology. 2004;62(9):1607–10.
10. Mori-Yoshimura M, Monma K, Suzuki N, Aoki M, Kumamoto T, Tanaka K,
et al. Heterozygous UDP-GlcNAc 2-epimerase and N-acetylmannosamine
kinase domain mutations in the GNE gene result in a less severe GNE
myopathy phenotype compared to homozygous N-acetylmannosamine
kinase domain mutations. J Neurol Sci. 2012;318(1–2):100–5.

Page 4 of 4

11. Leoyklang P, Class B, Noguchi S, Gahl WA, Carrillo N, Nishino I, et al.
Quantification of lectin fluorescence in GNE myopathy muscle biopsies.
Muscle Nerve. 2018;58(2):286–92.
12. Keppler OT, Hinderlich S, Langner J, Schwartz-Albiez R, Reutter W, Pawlita M.
UDP-GlcNAc 2-epimerase: a regulator of cell surface sialylation. Science.
1999;284(5418):1372–6.
13. Gagiannis D, Orthmann A, Danssmann I, Schwarzkopf M, Weidemann W,
Horstkorte R. Reduced sialylation status in UDP-N-acetylglucosamine-2epimerase/N-acetylmannosamine kinase (GNE)-deficient mice. Glycoconj J.
2007;24(2–3):125–30.
14. Malicdan MC, Noguchi S, Hayashi YK, Nonaka I, Nishino I. Prophylactic
treatment with sialic acid metabolites precludes the development of the
myopathic phenotype in the DMRV-hIBM mouse model. Nat Med. 2009;15(6):690–5.
15. Kitazume S, Imamaki R, Ogawa K, Taniguchi N. Sweet role of platelet
endothelial cell adhesion molecule in understanding angiogenesis.
Glycobiology. 2014;24(12):1260–4.
16. Li R, Hoffmeister KM, Falet H. Glycans and the platelet life cycle. Platelets.
2016;27(6):505–11.
17. Zhen C, Guo F, Fang X, Liu Y, Wang X. A family with distal myopathy withrimmed vacuoles associated with thrombocytopenia. Neurol Sci. 2014;35(9):1479–81.
18. Revel-Vilk S, Shai E, Turro E, Jahshan N, Hi-Am E, Spectre G, et al. GNE
variants causing autosomal recessive macrothrombocytopenia without
associated muscle wasting. Blood. 2018;132(17):1851–4.
19. Soule T, Phan C, White C, Resch L, Lacson A, Martens K, et al. GNE
myopathy with novel mutations and pronounced Paraspinal muscle
atrophy. Front Neurol. 2018;9:942.
20. Wu Y, Yuan L, Guo Y, Lu A, Zheng W, Xu H, et al. Identification of a GNE
homozygous mutation in a Han-Chinese family with GNE myopathy. J Cell
Mol Med. 2018;22(11):5533–8.

Publisher’s NoteSpringer Nature remains neutral with regard to jurisdictional claims inpublished maps and institutional affiliations.