[Disease spectrum and pathogenic genes of inherited metabolic disorder in Gansu Province of China]. / ç”˜è‚ƒåœ°åŒºé—ä¼ ä»£è°¢ç— ç–¾ç— è°±åŠè‡´ç— åŸºå› åˆ†æž.

OBJECTIVES: To investigate the disease spectrum and pathogenic genes of inherited metabolic disorder (IMD) among neonates in Gansu Province of China. METHODS: A retrospective analysis was conducted on the tandem mass spectrometry data of 286 682 neonates who received IMD screening in Gansu Provincial Maternal and Child Health Hospital from January 2018 to December 2021. A genetic analysis was conducted on the neonates with positive results in tandem mass spectrometry during primary screening and reexamination. RESULTS: A total of 23 types of IMD caused by 28 pathogenic genes were found in the 286 682 neonates, and the overall prevalence rate of IMD was 0.63 (1/1 593), among which phenylketonuria showed the highest prevalence rate of 0.32 (1/3 083), followed by methylmalonic acidemia (0.11, 1/8 959) and tetrahydrobiopterin deficiency (0.06, 1/15 927). In this study, 166 variants were identified in the 28 pathogenic genes, with 13 novel variants found in 9 genes. According to American College of Medical Genetics and Genomics guidelines, 5 novel variants were classified as pathogenic variants, 7 were classified as likely pathogenic variants, and 1 was classified as the variant of uncertain significance. CONCLUSIONS: This study enriches the database of pathogenic gene variants for IMD and provides basic data for establishing an accurate screening and diagnosis system for IMD in this region.

Prenatal sonographic diagnosis of X-linked hypohidrotic ectodermal dysplasia: An unusual case.

X-linked hypohidrotic ectodermal dysplasia (XLHED) is a rare congenital genetic disorder caused by mutations in the ectodysplasin A gene, resulting in dysplasia or complete absence of teeth, hair, and sweat glands. XLHED is rarely diagnosed prenatally. We describe a case of XLHED diagnosed with prenatal sonography and umbilical cord blood gene testing.

Analysis of spinal muscular atrophy carrier screening results in 32,416 pregnant women and 7,231 prepregnant women.

Objectives: Spinal muscular atrophy (SMA) is an autosomal recessive disease that is one of the most common in childhood neuromuscular disorders. Our screenings are more meaningful programs in preventing birth defects, providing a significant resource for healthcare professionals, genetic counselors, and policymakers involved in designing strategies to prevent and manage SMA. Method: We screened 39,647 participants from 2020 to the present by quantitative real-time PCR, including 7,231 pre-pregnancy participants and 32,416 pregnancy participants, to detect the presence of SMN1 gene EX7 and EX8 deletion in the DNA samples provided by the subjects. To validate the accuracy of our findings, we also utilized the Multiplex Ligation-dependent Probe Amplification (MLPA) to confirm the reliability of screening results obtained by quantitative real-time PCR. Result: Among the 39,647 participants who were screened, 726 participants were the carriers of SMN1. The overall carrier rate was calculated to be 1.83% (95% confidence interval: 0.86-2.8%). After undergoing screening, a total of 592 pregnancy carriers were provided with genetic counseling and only 503 of their spouses (84.97, 95% confidence interval: 82.09-87.85%) voluntarily underwent SMA screening. Conclusion: This study provides crucial insights into the prevalence and distribution of SMA carriers among the female population. The identification of 726 asymptomatic carriers highlights the necessity of comprehensive screening programs to identify at-risk individuals and ensure appropriate interventions are in place to minimize the impact of SMA-related conditions.

[Value of oral mucosa cast-off cells as samples in fluorescent in situ hybridization for the diagnosis of Down's syndrome].

OBJECTIVE: At present, blood and skin biopsy tissues are used in the fluorescent in situ hybridization (FISH) test for the diagnosis of Down's syndrome, however, the samples are usually obtained invasively. This study explores the value of oral mucosa cast-off cells in the FISH test, as samples obtained non-invasively, for the diagnosis of this disorder. METHODS: Peripheral blood and oral mucosa cast-off cells were sampled for the FISH test in 16 children with suspected Down's syndrome between March 2010 and March 2011. Chromosomal karyotype analysis of peripheral blood lymphocytes ("gold standard" for the diagnosis of Down's syndrome) was also conducted. RESULTS: The FISH test, in which both peripheral blood and oral mucosa cast-off cells were examined, showed that 14 children had 21-trosomy syndrome and the other 2 children had normal numbers of cromosome 21. The results of the FISH test were the same as the results of the chromosomal karyotype analysis. CONCLUSIONS: Use of the FISH method to test samples of oral musoca cast-off cells is non-invasive and reliable for the diagnosis of Down's syndrome in children, and is hence worthy of recommendation.

The Mutation Analysis of the AMT Gene in a Chinese Family With Nonketotic Hyperglycinemia.

Background: Nonketotic hyperglycinemia is a metabolic disease with autosomal recessive inheritance due to the glycine cleavage system (GCS) defect leading to the accumulation of glycine that causes severe and fatal neurological symptoms in the neonatal period. Methods: Genomic DNA was extracted from the peripheral blood of the female proband and her family members. The AMT variation was detected in the patient by whole-exome sequencing (WES), and the variant was validated by Sanger sequencing. Results: The WES showed that there were novel compound heterozygous frameshift variations c.977delA (p.Glu326Glyfs*12) and c.982_983insG (p.Ala328Glyfs*22) in exon eight of the AMT gene (NM_000481.4) in the proband. Genetic analysis showed that the former was inherited from the mother, and the latter was inherited from the father. Conclusion: We report the novel compound heterozygous variation of the AMT gene in a Chinese girl with NKH by WES, which has never been reported previously. Our case expanded the AMT gene mutation spectrum, further strengthened the understanding of NKH, and deepened the genetic and clinical heterogeneity of the disease. However, the study of treatment and prognosis is still our future challenge and focus.

[Mutation analysis of KIF21A gene in a Chinese family with congenital fibrosis of the extraocular muscles type I].

OBJECTIVE: To determine the mutation responsible for the congenital fibrosis of the extraocular muscles type I(CFEOM1) in a Chinese family. METHODS: Direct sequencing of exons 20 and 21 in the KIF21A gene was performed for the proband. The mutation c.2860C to T in exon 21 was examined by allele specific-PCR (AS-PCR) analysis in other family members. Haplotype analysis was performed using four STR markers (D12S1668, D12S2194, D12S331 and D12S1048). RESULTS: A heterozygous mutation c.2860C to T in the KIF21A gene was identified in all three affected members with CFEOM1. Haplotype analysis suggested that the mutation might derive from maternal germline mosaicism. CONCLUSION: This Chinese family with CFEOM1 may be caused by a c.2860C to T mutation in the KIF21A gene.

[Mutation analysis of the PAH gene in patients with phenylketonuria in Gansu province].

OBJECTIVE: To characterize the mutations of the phenylalanine hydroxylase (PAH) gene in patients with phenylketonuria in Gansu province. METHODS: Mutations of the PAH gene were detected in exons 3, 5, 6, 7, 11 and 12 with flaking introns of PAH gene by PCR and DNA sequencing. RESULTS: Mutations were identified in 45/58 alleles (detection rate: 96.4%), in total of 18 variants. Among them IVS12+5G>C was a novel mutation. The most frequent mutations were R243Q (22.7%), V399V (12.1%), EX6-96A>G (5.2%), R413P (5.2%) and IVS4-1G>A (5.2%), followed by Y356X (3.4%), R111X (3.4%) and INS7+2T>A (3.4%). CONCLUSION: The mutations of the phenylalanine hydroxylase gene in patients with phenylketonuria in Gansu province were similar to that in other areas of China, with obvious difference in mutation rate of some mutations.