PMC9884804_01
Changes in pulmonary imaging. (A) Consolidation of the bilateral lower lobe; (B) atelectasis of the posterior basal segment of the right lung.
fped-10-993165-g001.jpg
PMC9884804_01_fped-10-993165-g001.jpg
F1
A chest and abdominal CT scan indicated the presence of bilateral pneumonia (Figure 1) and pleural effusion, enlarged liver volume, a small effusion around the liver, a strip-shaped high-density focus in the gallbladder (nature to be determined), thickened bilateral abdominal wall muscle tissue, and atrophic bilateral erector spinal muscles. A spinal CT scan showed scoliosis of the lumbar spine and no bone destruction in each vertebral body.
Histochemical and immunohistochemical staining of muscle biopsies (x200). Following HE staining (A), different sizes of muscle fibers were observed, and degeneration, necrosis, and regeneration of the muscle fibers was evident as well as the deposition of amorphous materials. Some muscle fiber staining was significantly darker than the surrounding myofibrils according to modified Gomori trichrome staining (B). Fluorescence antibody staining of desmin, alpha-crystallin (C), and myotilin (D) revealed high expression levels of these proteins in the sediment.
fped-10-993165-g002.jpg
PMC9884804_01_fped-10-993165-g002.jpg
F2
Trichrome, ORO and PAS), enzyme histochemistry and special staining (NADH-TR, SDH, COX, SDH / COX, ATPase, ACP, AMP, NSE, phosphorylase and PFK), immunohistochemistry staining (Alexa Fluor or FITC labelled Desmin, alpha-Crystallin, Myotilin, titin, dystrophin, alpha, beta, gamma, delta-Sarcoglycan, Dysferlin, Lamininalpha2), and monoclonal antibody staining of Collagen VI were conducted in muscle biopsy. The Pathological results showed the accumulation of desmin, alpha-crystallin, and myotilin in the musculus biceps brachii, and dense granules were observed in muscle fibers using electron microscopy, which demonstrated myogenic fibromyopathy (Figure 2).
CRYAB gene sequences of the proband and her parents (mutation sites are marked with arrows). The CRYAB c.302A > C (p.H101P) mutation was located in the region of exon 3 of chromosome 11 and resulted in the mutation of the NO. 302 nucleotide from adenine to cytosine (A). The proband with FIHMM and her mother carried the same gene mutation; however, her father's gene locus was normal. The CRYAB 3G > A (p.M1I) mutation was located in the region of exon 2 of chromosome 11 and caused the mutation of a synthetic amino acid from methionine to isoleucine (B). The mutation carried by the proband was inherited from her unaffected father, whereas her mother's gene locus was normal.
fped-10-993165-g003.jpg
PMC9884804_01_fped-10-993165-g003.jpg
F3
The variant, CRYAB (NM_001885): c.302A > C (p.His101Pro), was located in the region of exon 3 of CRYAB, in which the NO.302 nucleotide was mutated from adenine to cytosine (c.302A > C), leading to a mutation of the NO.101 amino acid from histidine to proline (Figure 3A), which was inherited from currently asymptomatic, heterozygous carrier mother. The other variant, CRYAB (NM_001885): c.3G > A (p.Met1Ile) (provided in Data S.), inherited from her unaffected heterozygous carrier father, was located in the region of exon 2 of CRYAB (Figure 3B), in which the NO.3 nucleotide was mutated from guanine to adenine (c.3G > A), resulting in a mutation of the NO.1 amino acid from methionine to isoleucine.
Effect of the CRYAB c.302A > C (p.H101P) mutation on the three-dimensional structure of the protein predicted by functional model software. (A) Wide type and (B) mutant type. A hydrogen bond was absent in the mutation site of alphaB-crystallin.
fped-10-993165-g004.jpg
PMC9884804_01_fped-10-993165-g004.jpg
F4
The CRYAB c.302A > C (p.His101Pro) mutation affected the formation of a hydrogen bond (Figure 4), which influenced the three-dimensional structure of the CRYAB protein severely and caused functional defects, indicating the disease causing mutation.