Clinical and genetic analysis of a case with centronuclear myopathy caused by SPEG gene mutation: a case report and literature review

Figures

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  Fig. 1. a T2WIF transverse position shows the fat infiltration of the bilateral gluteus maximus (arrow 1), tensor fascia lata (arrow 2), and rectus femoris (arrow 3). b T2WI fat suppression transverse position shows swelling of the bilateral lateral femoris (arrow 1), rectus femoris (arrow 2), sartorius (arrow 3), and midfemoris muscle (arrow 4), intermuscular edema, and the obvious left side. c T2WI transection position shows the fat infiltration of the bilateral biceps femoris (arrow 1), semitendinosus (arrow 2), semimembranosus (arrow 3) and gracilis (arrow 4), and increased intermuscular fat

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  Fig. 2. Distribution of alterations across the schematic of SPEG. Domains are also indicated

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  Fig. 3. Two mutations in exon 13 of the SPEG gene in the child: c.3715 + 4C > T splicing mutation, derived from the father; c.3588delC frameshift mutation, derived from the mother; her younger sister carries the same mutation site

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  Fig. 4. Histological examination of the patient’s muscle biopsies: a The acid reaction series of ATPase showed checkerboard distribution of myofibers, and the pathology of type I myofibers was dominant. There are two types of atrophic myofibers, mainly type I. The diameter of type I myofiber is generally smaller than that of type II myofiber. b The alkaline reaction series of ATPase confirmed the abovementioned distribution characteristics of myofibers. Slightly atrophied-type II fiber is 15–25 μm in diameter. c HE staining shows that the nuclei of some myofibers are located in the center of the cell. d NADH1 staining showed that the center of some myofibers was slightly darker

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  Fig. 5. The mutation of the SPEG gene; c.3588delC was predicted by Mutation Taster to cause multiple Ig-like and protein kinase domains to be lost. The protein structure was predicted that a was wild type and b was mutant

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  Fig. 6. The result of cDNA PCR gel electrophoresis showed that the novel c.3715 + 4C > T splicing mutation produced an abnormal transcript; The PCR product of normal transcript was 608 bp, and that of abnormal transcript was 384 bp. SPEG cDNA forward primer: 5′-GAGCTGCCCGTTTCGACTGCAA-3′. SPEG cDNA reverse primer: 5′-GACCACATCTGTGACATACAGG-3′