Whole‐exome sequencing identified a novel pathogenic mutation of the CYP4F22 gene in a Chinese patient with autosomal recessive congenital ichthyosis and in vitro study of the mutant CYP4F22 protein

Abstract Background: Isolated sulfite oxidase deficiency (ISOD) is the rarest types of life-threatening neurometabolic disorders characterized by neonatal intractable seizures and severe developmental delay with an autosomal recessive mode of inheritance. ISOD is extremely rare and till date only 32 mutations have been identified and reported worldwide. Germline mutation in SUOX gene causes ISOD. Methods: Here, we investigated a 5-days old Chinese female child, presented with intermittent tremor or seizures of limbs, neonatal encephalopathy, subarachnoid cyst and haemorrhage, dysplasia of corpus callosum, neonatal convulsion, respiratory failure, cardiac failure, hyperlactatemia, severe metabolic acidosis, hyperglycemia, hyperkalemia, moderate anemia, atrioventricular block and complete right bundle branch block. Results: Whole exome sequencing identified a novel homozygous transition (c.1227G>A) in exon 6 of the SUOX gene in the proband. This novel homozygous variant leads to the formation of a truncated sulfite oxidase (p.Trp409*) of 408 amino acids. Hence, it is a loss-of-function variant. Proband’s father and mother is carrying this novel variant in a heterozygous state. This variant was not identified in 200 ethnically matched normal healthy control individuals. Conclusions: Our study not only expand the mutational spectrum of SUOX gene associated ISOD, but also strongly suggested the application of whole exome sequencing for identifying candidate genes and novel disease-causing mutations.

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Whole Exome Sequencing of Six Chinese Families With Hereditary Non-Syndromic Hearing Loss: A Genetic Etiology Study

10.21203/rs.3.rs-132767/v1 ◽

2020 ◽

Author(s):

Pengfei Liang ◽

Fengping Chen ◽

Shujuan Wang ◽

Qiong Li ◽

Wei Li ◽

...

Keyword(s):

Hearing Loss ◽

Exome Sequencing ◽

Whole Exome Sequencing ◽

Sanger Sequencing ◽

Large Scale ◽

Autosomal Recessive ◽

Autosomal Recessive Inheritance ◽

Chinese Families ◽

Whole Exome ◽

Syndromic Hearing Loss

Abstract Background: Hereditary non-syndromic hearing loss (NSHL) has a high genetic heterogeneity with >152 genes identified as associated molecular causes. The present study aimed to detect the possible damaging variants of the deaf probands from six unrelated Chinese families.Methods: After excluding the mutations in the most common genes, GJB2 and SLC26A4, 12 probands with prelingual deafness and autosomal recessive inheritance were evaluated by whole-exome sequencing (WES). All the candidate variants were verified by Sanger sequencing in all patients and their parents.Results: Biallelic mutations were identified in all deaf patients. Among these six families, 10 potentially causative mutations, including 3 reported and 7 novel mutations, in 3 different deafness-associated autosomal recessive (DFNB) genes (MYO15A, COL11A2, and CDH23) were identified. The mutations in MYO15A were frequent with 7/10 candidate variants. Sanger sequencing confirmed that these mutations segregated with the hearing loss of each family.Conclusions: Next-generation sequencing (NGS) approach becomes more cost-effective and efficient when analyzing large-scale genes compared to the conventional polymerase chain reaction-based Sanger sequencing, which is often used to screen common deafness-related genes. The current findings further extend the mutation spectrum of hearing loss in the Chinese population, which has a positive significance for genetic counseling.

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Juberg-Hayward syndrome is a cohesinopathy, caused by mutation in ESCO2

European Journal of Orthodontics ◽

10.1093/ejo/cjaa023 ◽

2020 ◽

Author(s):

Piranit Nik Kantaputra ◽

Prapai Dejkhamron ◽

Worrachet Intachai ◽

Chumpol Ngamphiw ◽

Katsushige Kawasaki ◽

...

Keyword(s):

Short Stature ◽

Exome Sequencing ◽

Whole Exome Sequencing ◽

Upper Limb ◽

Autosomal Recessive ◽

Cleft Lip ◽

Clinical Findings ◽

Protein Model ◽

Whole Exome ◽

Cleft Lip Palate

Summary Background Juberg-Hayward syndrome (JHS; MIM 216100) is a rare autosomal recessive malformation syndrome, characterized by cleft lip/palate, microcephaly, ptosis, short stature, hypoplasia or aplasia of thumbs, and dislocation of radial head and fusion of humerus and radius leading to elbow restriction. Objective To report for the first time the molecular aetiology of JHS. Patient and methods Clinical and radiographic examination, whole exome sequencing, Sanger sequencing, mutant protein model construction, and in situ hybridization of Esco2 expression in mouse embryos were performed. Results Clinical findings of the patient consisted of repaired cleft lip/palate, microcephaly, ptosis, short stature, delayed bone age, hypoplastic fingers and thumbs, clinodactyly of the fifth fingers, and humeroradial synostosis leading to elbow restriction. Intelligence is normal. Whole exome sequencing of the whole family showed a novel homozygous base substitution c.1654C>T in ESCO2 of the proband. The sister was homozygous for the wildtype variant. Parents were heterozygous for the mutation. The mutation is predicted to cause premature stop codon p.Arg552Ter. Mutations in ESCO2, a gene involved in cohesin complex formation, are known to cause Roberts/SC phocomelia syndrome. Roberts/SC phocomelia syndrome and JHS share similar clinical findings, including autosomal recessive inheritance, short stature, cleft lip/palate, severe upper limb anomalies, and hypoplastic digits. Esco2 expression during the early development of lip, palate, eyelid, digits, upper limb, and lower limb and truncated protein model are consistent with the defect. Conclusions Our study showed that Roberts/SC phocomelia syndrome and JHS are allelic and distinct entities. This is the first report demonstrating that mutation in ESCO2 causes JHS, a cohesinopathy.

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