Correction: Identification and In-Silico study of non-synonymous functional SNPs in the human SCN9A gene

[This corrects the article DOI: 10.1371/journal.pone.0297367.].

Identification and In-Silico study of non-synonymous functional SNPs in the human SCN9A gene

Single nucleotide polymorphisms are the most common form of DNA alterations at the level of a single nucleotide in the genomic sequence. Genome-wide association studies (GWAS) were carried to identify potential risk genes or genomic regions by screening for SNPs associated with disease. Recent studies have shown that SCN9A comprises the NaV1.7 subunit, Na+ channels have a gene encoding of 1988 amino acids arranged into 4 domains, all with 6 transmembrane regions, and are mainly found in dorsal root ganglion (DRG) neurons and sympathetic ganglion neurons. Multiple forms of acute hypersensitivity conditions, such as primary erythermalgia, congenital analgesia, and paroxysmal pain syndrome have been linked to polymorphisms in the SCN9A gene. Under this study, we utilized a variety of computational tools to explore out nsSNPs that are potentially damaging to heath by modifying the structure or activity of the SCN9A protein. Over 14 potentially damaging and disease-causing nsSNPs (E1889D, L1802P, F1782V, D1778N, C1370Y, V1311M, Y1248H, F1237L, M936V, I929T, V877E, D743Y, C710W, D623H) were identified by a variety of algorithms, including SNPnexus, SNAP-2, PANTHER, PhD-SNP, SNP & GO, I-Mutant, and ConSurf. Homology modeling, structure validation, and protein-ligand interactions also were performed to confirm 5 notable substitutions (L1802P, F1782V, D1778N, V1311M, and M936V). Such nsSNPs may become the center of further studies into a variety of disorders brought by SCN9A dysfunction. Using in-silico strategies for assessing SCN9A genetic variations will aid in organizing large-scale investigations and developing targeted therapeutics for disorders linked to these variations.

Echocardiographic features and behavior of cardiac structural abnormalities in mucopolysaccharidosis

Funding Acknowledgements

Type of funding sources: None.

Mucopolysaccharidosis (MPS) is a rare genetic lysosomal storage disorder with a wide variability of phenotype. A systematic descriptive study dealing with the echocardiographic (E) features of valvular involvement and their evolution over the time in adolescent and adult patients, whose number is growing up in adult echocardiographic laboratory, is lacking in the medical literature.

Purpose

To detect the E features of valvular involvement and their evolution in adolescent and adult patients.

Method

Study design: observational descriptive retrospective. Study group: 142 E studies in 17 adolescent and adult patients with diagnosis of MPS from 2001 until 2020. Mitral (M), aortic (A), tricuspid (T) valves (V) E features (thickness, mobility, calcification, and function), their evolution over the time and the behaviour with Enzyme replacement therapy (ERT) or bone marrow transplant (BMT) were assessed.

Result

52% male, mean age 21 yrs ranges 16 to 48 yrs. 5% of the patient had MPS type I, 11% MPS type II, 29% MPS type IV, and 52% MPS type VI. 70% received ERT and 11% BMT.

In the severe case all the valves were involved (panel A, B, C; white arrows point to valve leaflets; yellow arrows MV apparatus) the whole MV apparatus was involved since the earlier stage and in the latest stage the calcification was massive (panel C). The predominant valvular dysfunction was the regurgitation followed by mixed disorder while the most frequent severe lesion was the stenosis; the echocardiographic pattern differs from the classical hockey stick appearance of the early phase of rheumatic MV and the thickening is different from the myxomatous MV for the reduced mobility and the presence of calcification. The reduced mobility of the TV (panel C) also differs from the Loeffler syndrome because of the restriction of the leaflets and the association with thickening and calcification. Under treatment, the MV thickening was found to have a slow progression of less than 1 mm yearly in 61% cases.

Conclusion

Our results showed that all the valves are affected mainly the MV; the echocardiographic pattern of MPS, different from other valvular diseases of adolescent and adult age, can help in avoiding misdiagnose. Our observations also suggest that the cardiac involvement show slow rate of progression after the initiation of the therapy. Further studies are required to confirm our results.

Type of valve % of valve thickness % of reduced mobility % calcification diffuse % valve lesion Mitral valve 88% 65% 47% 75% Aortic valve 76% 23% 41% 57% Tricuspid valve 82% 47% 17% 52% Abstract Figure. Echocardiographic features

Genetic and phenotypic characterization of NKX6-2-related spastic ataxia and hypomyelination

Background and purpose

Hypomyelinating leukodystrophies are a heterogeneous group of genetic disorders with a wide spectrum of phenotypes and a high rate of genetically unsolved cases. Bi‐allelic mutations in NKX6‐2 were recently linked to spastic ataxia 8 with hypomyelinating leukodystrophy.

Methods

Using a combination of homozygosity mapping, exome sequencing, and detailed clinical and neuroimaging assessment a series of new NKX6‐2 mutations in a multicentre setting is described. Then, all reported NKX6‐2 mutations and those identified in this study were combined and an in‐depth analysis of NKX6‐2‐related disease spectrum was provided.

Results

Eleven new cases from eight families of different ethnic backgrounds carrying compound heterozygous and homozygous pathogenic variants in NKX6‐2 were identified, evidencing a high NKX6‐2 mutation burden in the hypomyelinating leukodystrophy disease spectrum. Our data reveal a phenotype spectrum with neonatal onset, global psychomotor delay and worse prognosis at the severe end and a childhood onset with mainly motor phenotype at the milder end. The phenotypic and neuroimaging expression in NKX6‐2 is described and it is shown that phenotypes with epilepsy in the absence of overt hypomyelination and diffuse hypomyelination without seizures can occur.

Conclusions

NKX6‐2 mutations should be considered in patients with autosomal recessive, very early onset of nystagmus, cerebellar ataxia with hypotonia that rapidly progresses to spasticity, particularly when associated with neuroimaging signs of hypomyelination. Therefore, it is recommended that NXK6‐2 should be included in hypomyelinating leukodystrophy and spastic ataxia diagnostic panels.

Woodhouse-Sakati syndrome in a family is associated with a homozygous start loss mutation in the DCAF17 gene

BACKGROUND

Woodhouse-Sakati syndrome (WSS) is a rare neuroendocrine and ectodermal disorder inherited in an autosomal recessive pattern. The syndrome presents prominent clinical features, including alopecia, neuroendocrine defects, neurological findings and progressive hearing loss. The condition results from mutations in the DCAF17 gene.

AIMS

To search for the underlying genetic defect in a Pakistani family with WSS phenotypes.

METHODOLOGY

Whole exome sequencing was used to search for the disease-causing variant.

RESULTS

Analysis of the exome data revealed a start loss sequence variant (c.1A>G, p.M1?) in DCAF17.

CONCLUSION

This variant is predicted to abolish translation of the DCAF17 polypeptide. To our knowledge, this is the first start loss variant identified in the DCAF17.

Marshall syndrome: further evidence of a distinct phenotypic entity and report of new findings

Marshall syndrome and type II Stickler syndrome are caused by mutations in COL11A1, which codes for the proα1chain of collagen XI. Collagen XI is a minor fibrillar collagen co-expressed with collagen II in cartilage and the vitreous of the eye. Characteristic features of Marshall syndrome include midfacial hypoplasia, high myopia, and sensorineural-hearing deficit. Deletions, insertions, splice site, and missense mutations in COL11A1 have been identified in Stickler syndrome and Marshall syndrome patients. In this study, we describe the clinical presentations of seven patients with Marshall syndrome from three unrelated Saudi families, inherited as autosomal dominant (two families) and autosomal recessive (one family). Cardinal clinical features of Marshall syndrome are manifested in all patients. One patient had ectodermal abnormalities. Mutations (c.2702G > A in exon 34,IVS50 + 1G > A, and IVS50 + lG > C) were identified in COL11A1 in affected members. Interestingly, the first report of autosomal recessive Marshall syndrome was from Saudi Arabia caused by the same mutation (c.2702G > A, p.Gly901Glu) as in one of our families. This study depicts detailed phenotypic and genetic description of dominant and recessive forms of Marshall syndrome due to COL11A1 mutations.