[Clinical and genetic characteristics of 9 rare cases with coexistence of dual genetic diagnoses].

Objective: To analyze the clinical and genetic characteristics of pediatric patients with dual genetic diagnoses (DGD). Methods: Clinical and genetic data of pediatric patients with DGD from January 2021 to February 2022 in Peking University First Hospital were collected and analyzed retrospectively. Results: Among the 9 children, 6 were boys and 3 were girls. The age of last visit or follow-up was 5.0 (2.7,6.8) years. The main clinical manifestations included motor retardation, mental retardation, multiple malformations, and skeletal deformity. Cases 1-4 were all all boys, showed myopathic gait, poor running and jumping, and significantly increased level of serum creatine kinase. Disease-causing variations in Duchenne muscular dystrophy (DMD) gene were confirmed by genetic testing. The 4 children were diagnosed with DMD or Becker muscular dystrophy combined with a second genetic disease, including hypertrophic osteoarthropathy, spinal muscular atrophy, fragile X syndrome, and cerebral cavernous malformations type 3, respectively. Cases 5-9 were clinically and genetically diagnosed as COL9A1 gene-related multiple epiphyseal dysplasia type 6 combined with NF1 gene-related neurofibromatosis type 1, COL6A3 gene-related Bethlem myopathy with WNT1 gene-related osteogenesis imperfecta type XV, Turner syndrome (45, X0/46, XX chimera) with TH gene-related Segawa syndrome, Chromosome 22q11.2 microduplication syndrome with DYNC1H1 gene-related autosomal dominant lower extremity-predominant spinal muscular atrophy-1, and ANKRD11 gene-related KBG syndrome combined with IRF2BPL gene-related neurodevelopmental disorder with regression, abnormal movement, language loss and epilepsy. DMD was the most common, and there were 6 autosomal dominant diseases caused by de novo heterozygous pathogenic variations. Conclusions: Pediatric patients with coexistence of double genetic diagnoses show complex phenotypes. When the clinical manifestations and progression are not fully consistent with the diagnosed rare genetic disease, a second rare genetic disease should be considered, and autosomal dominant diseases caused by de novo heterozygous pathogenic variation should be paid attention to. Trio-based whole-exome sequencing combining a variety of molecular genetic tests would be helpful for precise diagnosis.

[Analysis of 4 children with DYNC1H1 gene related spinal muscular atrophy with lower extremity predominant 1].

Objective: To investigate the clinical features and gene variation characteristics of children with dynein cytoplasmic 1 heavy chain 1 (DYNC1H1) gene associated spinal muscular atrophy with lower extremity predominant (SMALED) 1. Methods: The clinical data of 4 SMALED1 children admitted to Peking University First Hospital from December 2018 to May 2021, who were found to have pathogenic variation of DYNC1H1 gene through genetic testing, except for other genes known to be related to motor retardation, were retrospectively summarized to analyze the phenotype and genotype characteristics. Results: There were 3 males and 1 female. The age of onset was 1 year, 1 day, 1 day and 4 months, respectively. The age of diagnosis was 4 years and 10 months, 9 months, 5 years and 9 months, and 3 years and 1 month, respectively. The clinical manifestations were muscle weakness and muscular atrophy of lower limbs, 2 cases with foot deformity, 1 case with early non progressive joint contracture, 1 case with hip dislocation and 1 case with mental retardation. De novo heterozygous missense variations in DYNC1H1 gene were found in all 4 children. According to the rating of American College of medical genetics and genomics, they were all possible pathogenic and pathogenic variations, with p.R598C, p.P776L, p.Y1109D variations had been reported, and p.I1086R variation had not been reported. Conclusions: For those with unexplained lower limb muscle weakness, muscle atrophy, joint contracture and foot deformity, upper limb motor ability related retention, with or without mental retardation, as well as the motor ability progresses slowly, it is necessary to consider the possibility of SMALED1 and the detection of DYNC1H1 gene when necessary.

[Correlation between thigh muscle magnetic resonance imaging findings and clinical features of congenital muscular dystrophies: a preliminary study].

Objective: To analyze the clinical and magnetic resonance imaging (MRI) features of congenital muscular dystrophy (CMD) to improve the diagnostic level. Method: Clinical manifestations and thigh muscle MRI results of 8 cases of CMD diagnosed on genetic level from April 2013 to November 2015 were investigated. MRI was performed on the thigh muscles of all cases. Fatty infiltration of different muscles described in T1WI was graded to evaluate. Clinical symptoms and signs, as well as muscle MRI features were analyzed by statistical description. Result: Among these 8 cases, 2 cases were diagnosed with Ullrich congenital muscular dystrophy (UCMD), 1 case had rigid spine with muscular dystrophy type 1 (RSMD1), 1 case had LMNA related muscular dystrophy (L-CMD), 1 case had congenital muscular dystrophy 1C (MDC1C) and 3 cases had congenital muscular dystrophy 1A (MDC1A), with 4 were males and 4 females, aged from 0.9 year to 4.8 years (median age was 2.2 years). All of these 8 cases presented with muscle weakness and hypotonia from birth to within the first six months, together with delayed motor development and joint contractures. Some cases had spinal deformity or skin changes. Various degrees of fatty infiltration in gluteus maximus and thigh muscles were shown in all of the cases, and differences among CMD subtypes in the form of fatty infiltration were detected; muscle edema was present in 5 cases, and muscle atrophy in 7 cases. However, none of them has muscle hypertrophy. Semimembranous muscle absence was detected in 1 case. Conclusion: The clinical manifestations and thigh muscle MRI findings of CMD have some features, and vary in certain CMD subtypes. MRI examination combined with clinical features may provide useful information to select appropriate genetic or other diagnostic techniques, which may help clinicians to make accurate diagnosis.

[Expression of c-fos mRNA induced by pressure overload in the left ventricle].

In the present study the effect of pressure overload on the expression of protooncogene c-fos in the left ventricle was investigated in rats with abdominal aorta constriction. It was found that a remarkable expression of c-fos was induced by pressure overload and the expression was greatly attenuated by angiotensin converting enzyme inhibitor captopril. In the pressure overload group the angiotensinogen mRNA level was found increased. The above results suggest that angiotensin II is involved in the expression of c-fos due to pressure overload.

[Angiotensin II induces c-fos and c-myc proto-oncogene expression in the left ventricle].

In the present study, the effects of angiotension II on the expression of protooncogene c-fos and c-myc in the left ventricle were investigated on Langedorff heart preparations. It was observed that angiotensin induced both c-fos and c-myc expression in a dose-dependent manner and the c-fos expression showed an earlier appearance than c-myc. All these induced expressions were blocked by a Angiotensin II receptor antagonist saralasin. The Angiotensin II induced expression of c-fos was also blocked by TTX, but the c-myc gene expression was unaffected.