Detection of a novel PAX6 variant in a Chinese family with multiple ocular abnormalities

Background Aniridia is a congenital, panocular disease that can affect the cornea, anterior chamber angle, iris, lens, retina and optic nerve. PAX6 loss-of-function variants are the most common cause of aniridia, and variants throughout the gene have been linked to a range of ophthalmic abnormalities. Furthermore, particular variants at a given site in PAX6 lead to distinct phenotypes. This study aimed to characterize genetic variants associated with congenital aniridia in a Chinese family. Methods The proband and family underwent ophthalmologic examinations. DNA was sampled from the peripheral blood of all 6 individuals, and whole-exome sequencing was performed. Sanger sequencing was used to verify the variant in this family members. Results A novel variant (c.114_119delinsAATTTCC: p.Pro39llefsTer17) in the PAX6 gene was identified in subjects II-1, III-1 and III-2, who exhibited complete aniridia and cataracts. The proband and the proband’s brother also had glaucoma, high myopia, and foveal hypoplasia. Conclusions We identified that a novel PAX6 frameshift heterozygous deletion variant is the predominant cause of aniridia in this Chinese family. Trial registration We did not perform any health-related interventions for the participants.

Novel variants in PDE6A and PDE6B genes and its phenotypes in patients with retinitis pigmentosa in Chinese families

Background Retinitis pigmentosa (RP) is a genetically heterogeneous disease with 89 causative genes identified to date. However, only approximately 60% of RP cases genetically solved to date, predicating that many novel disease-causing variants are yet to be identified. The purpose of this study is to identify novel variants in PDE6A and PDE6B genes and present its phenotypes in patients with retinitis pigmentosa in Chinese families. Methods Five retinitis pigmentosa patients with PDE6A variants and three with PDE6B variants were identified through a hereditary eye disease enrichment panel (HEDEP), all patients’ medical and ophthalmic histories were collected, and ophthalmological examinations were performed, followed by an analysis of the possible causative variants. Sanger sequencing was used to verify the variants. Results We identified 20 variants in eight patients: 16 of them were identified in either PDE6A or PDE6B in a compound heterozygous state. Additional four heterozygous variants were identified in the genes ADGRA3, CA4, OPTN, RHO. Two novel genetic changes in PDE6A were identified (c.1246G > A and c.1747 T > A), three novel genetic changes in PDE6B were identified (c.401 T > C, c.2293G > C and c.1610-1612del), out of the novel identified variants one was most probably non-pathogenic (c.2293G > C), all other novel variants are pathogenic. Additional variant was identified in CA4 and RHO, which can cause ADRP (c.243G > A, c.688G > A). In addition, a novel variant in ADGRA3 was identified (c.921-1G > A). Conclusions This study reveals novel and known variants in PDE6A and PDE6B genes in Chinese families with autosomal recessive RP, and expands the clinical and genetic findings of photoreceptor-specific enzyme deficiencies.

Right retrocolic intrasaccular duodenum: Is it a novel variant of isolated duodenal nonrotation? A case report

Background: Almost all of the studies on anomalies of the midgut rotation and fixation in the literature and related sections in textbooks were designed according to Dott's classification. Focusing only on common rotation anomalies has led to the exclusion and neglect of other rare variants. Isolated pure duodenal nonrotation is such a variant. Case Presentation: We report a case of an unusual form of isolated pure duodenal nonrotation, in a 3-day-old newborn presenting with bilious vomiting. Ultrasonographic examination revealed the sign of 'whirlpool'. When this finding was evaluated together with bilious vomiting, midgut volvulus was considered and the patient was operated on urgently. Peroperatively, it was observed that the jejunum entered between the leaves of the terminal ileum mesentery. Proximally, the duodenum was located posterior to the right colon in a "sack". This "sack" was surrounded by thick Ladd's bands laterally, mesentery of the ascending colon medially, the posterior surface of the cecum and ascending colon anteriorly, and by the posterior abdominal wall posteriorly. Conclusion: In isolated duodenal nonrotation, the duodenum may be completely retro-colic. Consequently, the duodenojejunal junction and the ileocecal region may almost overlap. Unlike isolated duodenal nonrotation cases, in the surgical treatment of this variant, separation of Ladd bands alone is not sufficient, additionally, the right colon should be placed in a nonrotation position and care should be taken not to kink the terminal ileum under the cecum.

Comprehensive Genetic Analysis of RASopathy in the Era of Next-Generation Sequencing and Definition of a Novel Likely Pathogenic KRAS Variation

<b><i>Introduction:</i></b> Germline pathogenic variations of the genes encoding the components of the Ras-MAPK pathway are found to be responsible for RASopathies, a clinically and genetically heterogeneous group of diseases. In this study, we aimed to present the results of patients genetically investigated for RASopathy-related mutations in our Genetic Diagnosis Center. <b><i>Methods:</i></b> The results of 51 unrelated probands with RASopathy and 4 affected relatives (31 male, 24 female; mean age: 9.327 ± 8.214) were included in this study. Mutation screening was performed on DNA samples from peripheral blood of the patients either by Sanger sequencing of <i>PTPN11</i> hotspot regions (10/51 probands), or by a targeted amplicon next-generation sequencing panel (41/51 probands) covering the exonic regions of <i>BRAF</i>, <i>CBL</i>, <i>HRAS</i>, <i>KRAS</i>, <i>LZTR1</i>, <i>MAP2K1</i>, <i>MAP2K2</i>, <i>NF1</i>, <i>NRAS</i>, <i>PTPN11</i>, <i>RAF1</i>, <i>RASA2</i>, <i>RIT1</i>, <i>SHOC2</i>, <i>SOS1</i>, <i>SOS2</i>, <i>SPRED1</i>, and <i>KAT6B</i> genes. <b><i>Results:</i></b> Pathogenic/likely pathogenic variations found in 22 out of 51 probands (43.13%) and their 4 affected family members were located in <i>PTPN11</i>, <i>BRAF</i>, <i>KRAS</i>, <i>NF1</i>, <i>RAF1</i>, <i>SOS1</i>, and <i>SHOC2</i> genes. The c.148A&#x3e;C (p.Thr50Pro) variation in the <i>KRAS</i> gene was a novel variant detected in a sibling in our patient cohort. We found supportive evidence for the pathogenicity of the <i>NF1</i> gene c.5606G&#x3e;T (p.Gly1869Val) variation which we defined in an affected boy who inherited the mutation from his affected father. <b><i>Conclusion:</i></b> Although <i>PTPN11</i> is the most frequently mutated gene in our patient cohort, as in most previous reports, different mutation distribution among the other genes studied motivates the use of a next-generation sequencing gene panel including the possible responsible genes.

Clinical, pathological and molecular spectrum of patients with glycogen storage diseases in Pakistan

Objectives Evaluation of clinical, biochemical and molecular analysis of Pakistani patients with hepatic GSDs. Methods Medical charts, biochemical, histopathological and molecular results of patients with hepatic GSD were reviewed. Results Out of 55 GSD patients, 41 (74.5%) were males and 14 (25.5%) were females with consanguinity in 50 (91%) patients. The median age of initial symptoms, clinic diagnosis and molecular diagnosis were 450 (IQR: 270–960), 1,095 (IQR: 510–1,825) and 1717 (IQR: 796–3,011) days, respectively. Molecular analysis and enzyme activity was available for 33 (60%) and two patients, respectively. GSD III (n=9) was most prevalent followed by GSD Ib (n=7), GSD IXc (n=6), GSD VI (n=4), GSD Ia (n=3), GSD XI (n=3), GSD IXb (n=2) and GSD IXa (n=1). In patients (n=33) who underwent molecular analysis; 19 different variants in eight genes associated with GSD were identified. We also report five novel variants, two in SLC37A4, one in AGL and two in PYGL contributing to the diagnosis of GSD Ib, GSD III and GSD VI, respectively. Conclusions Fifty-five patients of GSDs in 26 families from a single care provider indicate a relatively high frequency of GSD in Pakistan, with multiple unrelated families harboring identical disease-causing variants, on molecular analysis, including two known pathogenic variants in SLC37A4 and PHKG2, and a novel variant in AGL.

Three Novel Variants of CEP290 and CC2D2DA and a Link Between ZNF77 and SHH Signaling Pathway Are Found in Two Meckel-Gruber Syndrome Fetuses

Meckel-Gruber syndrome (MKS) is a rare lethal autosomal recessive inherited disorder. Missed diagnosis might happen in clinical works due to an unclear genotype–phenotype correlation. We analyzed two families visiting our center; the parents are normal; each of the family aborted a fetus at 12WG. Following ultrasonography and pathological examination, both were diagnosed as MKS. Whole exome sequencing identified a compound heterozygous of two novel variants of CEP290 and a heterozygous of a novel variant of CC2D2A. Frameshift mutations in ZNF77 were also detected. Western blot analyzing whole-brain tissue showed that the expression of ZNF77, CC2D2A, and CEP290 was enhanced. HEK293T transfected with over-expression wildtype/mutated ZNF77 plasmid showed that SHH was increased in wildtype ZNF77 cells, while SHH and CC2D2A were increased in mutated ZNF77 cells. Our research provided two novel pathogenic variants of CEP290 and CC2D2A and suggested that ZNF77 might promote the expression of CC2D2A and regulate the amount of SHH.

Cochlear implantation in a Chinese patient with a novel frameshift variant in POU3F4 gene and incomplete partition type III: a case report

Variations in the POU Class 3 Homeobox 4 ( POU3F4) gene are associated with X-linked mixed deafness. Here, the identification of a novel variant of POU3F4 in a male paediatric patient (the proband) with incomplete partition type III (IP-III) hearing impairment, is described. Clinical data were collected from the proband and his biological parents. Whole exome sequencing of the proband revealed a novel frameshift insertion mutation in POU3F4 (c.717_718ins GTGCCTTGCAG : p.Leu240Valfs*5) in a hemizygous state. This variant likely truncates the protein within the POU-specific domain, and the proband’s biological mother was found to be a carrier of this variant. After excluding all contraindications, the proband underwent cochlear implantation in the right ear in June 2020. Cerebrospinal fluid (CSF) gushing was observed during surgery, but there were no postoperative complications, such as CSF leak, meningitis, or facial nerve stimulation. A novel pathogenic frameshift variant of POU3F4 was identified, enriching the known mutation spectrum of POU3F4. Effective perioperative prevention and response measures should be taken to reduce the incidence of CSF gushing and meningitis in patients receiving IP-III cochlear implantation.