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MYH9-related disorders: a rare cause of neonatal thrombocytopaenia
  1. Maria Inês Marques1,2,
  2. Luísa Carrington Queiró1,
  3. Ana Rita Prior3,
  4. Madalena Lopo Tuna3
  1. 1Paediatric Department, Centro Hospitalar de Lisboa Ocidental EPE, Lisboa, Portugal
  2. 2Paediatric Department, Centro Hospitalar Tondela-Viseu, Viseu, Portugal
  3. 3Neonatal Intensive Care Unit, Centro Hospitalar de Lisboa Ocidental EPE, Lisboa, Portugal
  1. Correspondence to Dr Maria Inês Marques, mariainesmarques{at}


Myosin heavy chain 9-related disorders (MYH9RD) are a genetic condition characterised by large platelets and thrombocytopaenia. The May-Hegglin anomaly (MHA), an uncommon condition with a potential risk of bleeding complications once thought to be separate, is now known to be part of MYH9RD.

There are very limited data on the clinical course and neonatal/paediatric outcome in children with MHA. We present the case of a newborn with a normal physical examination whose mother had MHA. Peripheral blood examination revealed a platelet count of 16×109/L with giant platelets and neutrophils containing Döhle bodies. Neonatal brain ultrasound examination showed no haemorrhage. The infant received three platelet transfusions during the first 29 days of life, remaining asymptomatic. The genetic molecular test was positive for MYH9RD. It is important to identify at-risk infants with this condition and to initiate therapy to prevent related complications, if needed, in a multidisciplinary team approach.

  • neonatal health
  • preventative paediatrics
  • materno-fetal medicine
  • congenital disorders

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  • Contributors All authors, in addition to being involved in the patient’s care, made an individual contribution to the writing of this article and approve the version submitted. MIM, ARP, MLT: were present at the birth of this child, which forced us to research and inspired us to share this challenge. LCQ: followed up the patient during her hospitalisation. MIM, LCQ: did the main research for this article, its design and conception. ARP, MLT: reviewed the article. All authors reviewed and agree with all the changes suggested by the reviewers.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Provenance and peer review Not commissioned; externally peer reviewed.