Microcephaly-seizures-development delay syndrome in a pedigree: genetic analysis and literature review / 中华围产医学杂志

Objective:To analyze the phenotypes and genetic etiology of microcephaly- seizures-development delay (MCSZ) syndrome.Methods:The patient was diagnosed with MCSZ syndrome in June 2018 at Shenzhen Maternity and Child Healthcare Hospital. She was the couple's first child, and the mother conceived a second child in 2020. The clinical data of the proband were retrospectively analyzed, and the bioinformatics analysis and whole-exome sequencing (WES) were performed on the proband and her parents to identify the pathogenic variants, which were further validated using Sanger sequencing. The prenatal genetic diagnosis of the second fetus was performed following the molecular diagnosis of the proband was confirmed. The clinical manifestations and pathogenesis of MCSZ syndrome were summarized by reviewing related literature.Results:(1) Case report: The patient, an eight-month-old girl, was admitted to our hospital due to microcephaly and repeated seizures. Another clinical characteristic was mental retardation. Auditory evoked potential detected moderate impairment of the left auditory nerve pathway. WES showed a compound heterozygous variation in the PNKP gene of the proband. Moreover, the pathogenic variation, c.199-10_203delinsTCTGAGGGGT, was inherited from the father, and the likely pathogenic variation, c.1505C>T(p.P502>L), was inherited from the mother, which was both de novo mutations. The compound heterozygous variation in the PNKP gene was considered genetic etiology based on the genetic testing and clinical features. Prenatal diagnosis showed that the second fetus did not inherit the PNKP gene variants from the parents and the couples chose to continue the pregnancy. A girl was born, and her psychomotor development and occipitofrontal size circumference were normal at 13 months old. (2) Literature review: 39 MCSZ syndrome cases were retrieved, including the present case and 38 cases from 12 relevant literature. The clinical characteristics were microcephaly (91.7%, 33/36), seizures (88.2%, 30/34), development delay (96.4%, 27/28), hyperactivity (25.6%, 9/39), gastroesophageal reflux (10.3%, 4/39), and hearing loss (7.7%, 3/39). Most patients' first onset of epilepsy was in infancy (96.3%, 26/27). Cranial MRI examination showed brain dysplasia in 31 cases (91.2%, 31/34). Conclusions:When the fetal head circumference is smaller than normal and is progressively reduced combined with postnatal microcephaly, epilepsy, developmental retardation, hyperactivity disorder, gastroesophageal reflux, and hearing loss, MCSZ syndrome should be considered. The prognosis varies widely, and genetic testing facilitates the early diagnosis and genetic counseling of MCSZ syndrome.

Prenatal diagnosis of Aicardi-Goutières syndrome type 3: report of two pedigrees / 中华围产医学杂志

Two pedigrees are reported here including two siblings and a boy who were diagnosed with Aicardi-Goutières syndrome type 3 (AGS3) caused by compound heterozygous variation of RNASEH2C gene. Prenatal gene diagnosis was performed when their mothers were pregnant again. All three cases presented with epilepsy, microcephaly, muscular hypertonia and severe language, motor and mental retardation. In pedigree 1, genetic analysis showed compound heterozygous variants of c.194G>A (p.Gly65Asp) and c.434G>T (p.Arg145Leu) in the RNASEH2C gene of proband 1 and her younger brother, which were inherited from their mother and father respectively. While in pedigree 2, c.194G>A(p.Gly65Asp) and c.227C>T(p.Pro76Leu) compound heterozygous variants in the RNASEH2C gene were found in proband 2, which were inherited from his father and mother, respectively. Diagnosis of AGS3 was confirmed in these three cases based on their medical history and the testing results. The mothers from the two families underwent prenatal diagnosis in their subsequent pregnancy, and the variation only inherited from the mothers was detected, suggesting that the two fetuses are carriers. Both families chose to continue the pregnancy and delivered at full-term. No growth or development abnormalities were reported in the children during a one-year follow-up.

The Influence of Fibrin on the Reaction of Plasminogen Activation by Mut ant of Pro-Urokinase / 生物化学与生物物理进展

Because the influence of fibrin on the reaction of plasm inogen activation by various plasminogen activators is different, the kinetic co nstant of the reaction of plasminogen activation catalyzed by InB with and witho ut fibrin were detected. The result is: Kfibrinm＝4.2 μmol*L -1，greater than the normal Km=0.379 μmol*L-1; kfib rincat＝0.107 s-1，greater than the normal kcat=0.0165 s-1. The results suggest that existence of fibrin in the reaction system of plasminogen activation depress the affinity between InB and plasminog en, but accelerates the hydrolysis of plasminogen by InB. The count up effect is inhibition.

Characterization of Bifunctional Chimeric Molecule of PRGDWR Containing Pro-Urokinase / 生物化学与生物物理进展

In order to obtain the bifunctional chimeric molecule of single-chain urokinase-type plasminogen activator (scu-PA) which can inhibit platelet aggregation, PRGDWR peptide was inserted into the site between Gly 118 and Leu119 (called insertion mutant B, InB). The recombinant gene of InB was expressed by Pichia pastoris. The secreted protein was purified by metal chelate affinity and strong cation exchange chromatography. The amidolytic ability of mutant InB is 5 900 IU/mg, the kinetic constants is: KInB m,plg=56.8 μmol*L-1，kInBcat,plg=0.33 s- 1. The kinetic constants of plasminogen activation reaction is: KInB m,plg=0.397 μmol*L-1，kInBcat,plg=0.0164 s-1. Fibrin inhibit the catalytiv ability of InB during plasminogen activatio n, the influence factor is 0.463(means InB remain 46.3% of the catalytic abili ty when fibrin was involved in the reaction system). The mutant not only has alm ost the same catalytic ability as wild type scu-PA, but also has strong ability of anti-platelet aggregation(compared with scu-PA), IC50 of InB is 12.7 μmol*L-1.