PMC10203705_01
Clinical image presentation of the proband. (A) ECG recording demonstrated abnormal signals in right atrial, suspected right ventricular hypertrophy, sinus tachycardia, and ST segment changes (lead I, II, III, aVF, and V3-V6 depression of 0.1-0.5 mV and aVR and V1 increase by 0.1-0.2 mV). (B) Echocardiography revealed type I truncus arteriosus. (C) Cerebral CT examination demonstrated bilateral cerebral hemispheric parenchyma atrophy at 9 months old. (D) Cerebral MRI identified aggressive atrophy at 12 months old.
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An electrocardiogram (ECG) revealed abnormal signals in the right atrium and suspected right ventricular hypertrophy, as well as sinus tachycardia and ST segment changes (depression in lead I, II, III, aVF, and V3-V6 of 0.1-0.5 mV and an increase in aVR and V1 of 0.1-0.2 mV), as illustrated in Figure 1A. The echocardiogram identified a severe type of CHD, type I truncus arteriosus, with ventricular septal defect (VSD) and patent foramen ovale (PFO) (Figure 1B). The neurological system was assessed through cranial computed tomography (CT) scanning, which showed the presence of bilateral apical, occipital, and temporal subdural effusions; slightly wider bilateral lateral ventricles and annular cisterns; and bilateral cerebral hemispheric parenchyma atrophy (Figure 1C). A summary of all reported variants of TMEM260 is presented in Figure 2D and Table 1. The patient also experienced regression in motor performance, and a follow-up cranial CT scan revealed aggressive progression of cerebral atrophy (Figure 1D).
Molecular analysis of TMEM260 variants. (A) Family pedigree of the proband. (B) The prevalence of the TMEM260 variant identified in the proband. (C) Molecular structure based on the AF-Q9NX78-F1 template. (D) Reported variants of the TMEM260 gene.
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The c.1336_1339DEL homozygous variant was found to result in a frameshift mutation in the amino acid sequence (p.L447Vfs*9). The parents of the proband were found to be carriers of the variant by WES analysis and did not exhibit any clinical manifestations (Figure 2A). The frequency of this mutation in the general population is not recorded in any database (Figure 2B). TMEM260 gene. This led to a change in amino acid 447 from leucine to valine and the creation of a stop codon after the ninth amino acid, causing a structural deletion in the TMEM260 protein and resulting in the loss of gene function (Figure 2C). A summary of all reported variants of TMEM260 is presented in Figure 2D and Table 1.