ABSTRACT
Objective:
To summarize the clinical characteristics and
gene variants of 2 pedigrees of non-
muscle myosin heavy chain 9 related
diseases (MYH9-RD) in
children.
Methods:
The basic information, clinical features,
gene variants and
laboratory tests of MYH9-RD
patients from 2 pedigrees confirmed in the First Affiliated
Hospital of Zhengzhou
University in November 2021 and July 2022 were analyzed retrospectively. "Non-
muscle myosin heavy chain 9 related
disease" "MYH9" and "
children" were used as key words to search at
Pubmed database, CNKI and Wanfang database up to February 2023. The MYH9-RD
gene variant spectrum and clinical data were analyzed and summarized.
Results:
Proband 1 (
male, 11 years old) sought medical
attention due to
epistaxis, the eldest
sister and second
sister of proband 1 only showed excessive menstrual
bleeding, the
skin and
mucous membrane of the their
mother were prone to
ecchymosis after bumping, the uncle of proband 1 had
kidney damage, and the maternal
grandmother and maternal great-
grandmother of proband 1 had a
history of
cataracts. There were 7 cases of phenotypic
abnormalities in this
pedigree.
High-throughput sequencing showed that the proband 1 MYH9
gene had c.279C>G (p.N93K) missense variant, and
family verification
analysis showed that the variant was inherited from the
mother. A total of 4
patients including proband 1 and
family members were diagnosed with MYH9-RD. The proband 2 (
female, 1 year old) sought medical
attention duo to
fever and
cough, and the
father's
physical examination revealed
thrombocytopenia. There were 2 cases of phenotypic
abnormalities in this
pedigree.
High-throughput sequencing showed that there was a c.4270G>A (p.D1424N) missense variant in the proband 2 MYH9
gene, and
family verification
analysis showed that the variant was inherited from the
father. A total of 2
patients including proband 2 and his
father were diagnosed with MYH9-RD. A total of 99 articles were retrieved, including 32 domestic
literatures and 67 foreign
literatures. The MYH9-RD cases totaled 149 pedigrees and 197 sporadic
patients, including 2 pedigrees in our study. There were 101 cases with complete clinical data, including 62 sporadic cases and 39 pedigrees. There were 56
males and 45
females, with an average age of 6.9 years old. The main clinical manifestations were
thrombocytopenia,
skin ecchymosis, and
epistaxis. Most
patients didn't receive special
treatment after
diagnosis. Six English
literatures related to MYH9-RD caused by c.279C>G
mutation in MYH9
gene were retrieved.
Italy reported the highest number of cases (3 cases). Twelve
literatures related to MYH9-RD caused by c.4270G>A
mutation in MYH9
gene were retrieved.
China reported the highest number of cases (9 cases).
Conclusions:
The clinical manifestations of
patients in the MYH9-RD pedigrees varied greatly. MYH9
gene c.279C>G and c.4270G>A
mutations are the cause of MYH9-RD.