A novel MAPT variant (E342K) as a cause of familial progressive supranuclear palsy.

Background: MAPT variants are a known cause of frontotemporal dementia and Parkinsonian syndrome, of which progressive supranuclear palsy syndrome (PSP) is a rare manifestation. Objective: To report a novel MAPT variant in a PSP pedigree with autosomal dominant inheritance pattern, and to produce a literature review of PSP patients with MAPT variants. Methods: A comprehensive clinical, genetic, and molecular neuroimaging investigation was conducted on a 61 years-old female proband diagnosed with PSP. We also collected the clinical presentation data and history of the patient's pedigree, and performed further genetic analysis of 4 relatives, from two generations, with and without symptoms. Results: The proband exhibited typical clinical manifestation of PSP. A cranial MRI revealed midbrain atrophy, and an FDG-PET scan suggested hypo-metabolic changes in caudate nucleus, left prefrontal lobe, both temporal poles, and midbrain. 18F-florzolo-tau-PET revealed tau-protein deposits in the thalamus and brainstem bilaterally. A gene test by whole-exome sequencing identified a novel MAPT variant [NM_005910.6, exon 11, c.1024G > A (p.E342K)], and the same variant was also identified in one affected relative and one asymptomatic relative, a probable pre-symptomatic carrier. Conclusion: The PSP pedigree caused by the novel MAPT (E342K) variant, expanded the mutational spectrum of MAPT.

Case report: Whole exome sequencing and genome-wide methylation profiling of Czech dysplasia in a Chinese pedigree.

Background: Czech dysplasia is a rare skeletal disorder with symptomatology including platyspondyly, brachydactyly of the third and fourth toes, and early-onset progressive pseudorheumatoid arthritis. The disorder segregates in an autosomal dominant fashion. A specific missense mutation (R275C, c.823C > T) in exon 13 of the COL2A1 gene has been identified in German and Japanese families. Case summary: We present the case of a Chinese woman diagnosed with Czech dysplasia (proband) who carried a variant in the COL2A1 gene. Whole-exome sequencing (WES) identified the COL2A1 missense mutation (R275C, c.823C > T) in close relatives of the proband who also exhibited the same disorder. Conclusion: This study is a thorough clinical and physiological description of Czech dysplasia in a Chinese patient.

Two Novel and a Recurrent ATP2C1 Mutations in Chinese Population with Hailey-Hailey Disease.

Purpose: Hailey-Hailey disease (HHD), also known as familial benign chronic pemphigus, is a rare autosomal dominant inherited blistering dermatosis. Pathogenic variants in ATP2C1 have been associated with HHD since 2000. This study aimed to identify the mutations in the ATP2C1 gene in two Chinese pedigrees and two sporadic cases with HHD. Patients and Methods: Two Chinese pedigrees and two sporadic cases were included in this study. Whole-exome sequencing and Sanger sequencing were performed to detect the mutation of the ATP2C1 gene. Predictions of protein structure and function were performed using bioinformatics tools, including Mutation Taster, Polyphen-2, SIFT, and Swiss-Model. Results: In this study, we detected three heterozygous mutations, including novel compound mutations of (c.1840-4delA and c.1840_1844delGTTGC), splice site mutation of c.1570+3A>C, and a previously known nonsense mutation c.1402C>T in the ATP2C1 gene. Combined with our previous study, ten patients with c.1402C>T mutation in the ATP2C1 gene have been identified, and all these patients originated from Jiangxi Province. Conclusion: c.1402C>T mutation in the ATP2C1 gene was considered a regional highly prevalent mutation in the Chinese population with HHD. The results added new variants to the database of ATP2C1 mutations associated with HHD.

Case Report: Novel TRPM6 Mutations Cause Hereditary Hypomagnesemia With Secondary Hypocalcemia in a Chinese Family and a Literature Review.

Background: Hereditary hypomagnesemia with secondary hypocalcemia (HSH) is a rare autosomal recessive disease due to biallelic TRPM6 mutations. Although the reports of HSH caused by TRPM6 mutations are not very rare, the age of onset in previously reported HSH cases were <1 year. Methods: We collected and analyzed the clinical data of twin brothers with onset age over 1 year old and performed whole exome sequencing in the patients and their parents. Confirmed by Sanger sequencing, missense mutation was analyzed in silico. We also searched Pubmed, and extracted clinical data from case reports and case series with full text in English, reporting original data of patients with TRPM6 mutations. Results: The twin patients had canonical HSH phenotype with compound novel TRPM6 mutations, p.T87K and c.705dupT, inherited from their father and mother, respectively. T87 is a highly conserved site and T87K is predicted to cause hydrogen bond disruption. We identified 26 articles published between May 28, 2002 to December 31, 2021 which reported a total of 88 patients with TRPM6 mutation. We found that the most common clinical phenotypes were hypomagnesemia, hypocalcemia, and convulsions. However, the age of onset in HSH patients almost always occurred under 12 months old, the twin patients of our study were 18 and 26 months old at onset. Conclusion: We identified two novel TRPM6 mutations in a Chinses family with HSH, and showed that the age of onset with c.704c-c.705(exon7)insT and c.260(exon4)C>A mutation in TRPM6 was much later than other mutations and would be much less serious.

H258R mutation in KCNAB3 gene in a family with genetic epilepsy and febrile seizures plus.

PURPOSE: The aim of this was to discover disease-causing gene mutations linked to genetic epilepsy with febrile seizures plus (GEFS+) in a family in the Southern Chinese Han population. Of a three-generation pedigree of 18 members in this family, 4 were affected with GEFS+. METHOD: Blood samples of 7 family members-3 affected and 4 unaffected individuals-were collected. Whole-exome sequencing was performed to assess for genetic mutations in two of the affected individuals and two of the unaffected individuals. RESULTS: Fourteen potentially consequential mutations were found in the two affected individuals and were validated with the Sanger sequencing method. Blood DNA tested in polymerase chain reaction with KCNAB3 primers revealed that one novel missense mutation, c.773A>G (p.H258R) in the KCNAB3 gene, which encoded the potassium voltage-gated channel subfamily A regulatory ß subunit 3 (KCNAB3), was shared by all three affected and one unaffected family member. However, this mutation did not appear in 300 unrelated control subjects. According to the bioinformatics tools SIFT and PROVEAN, p.H258R was thought to affect protein function. Functional verification showed that the KCNAB3 mutation could accelerate the inactivation of potassium channels, thus inhibiting potassium current, increasing neuronal excitability, and promoting epileptic convulsion. CONCLUSIONS: These results reveal that mutations in the KCNAB3 gene may be associated with GEFS+.

A rare frameshift variant in trans with the IVS9-5T allele of CFTR in a Chinese pedigree with congenital aplasia of vas deferens.

PURPOSE: Congenital aplasia of vas deferens (CAVD) is an atypical form of cystic fibrosis (CF) and causes obstructive azoospermia and male infertility. Compound heterozygous variants of CFTR are the main cause of CAVD. However, most evidence comes from genetic screening of sporadic cases and little is from pedigree analysis. In this study, we performed analysis in a Chinese pedigree with two CAVD patients in order to determine the genetic cause of this familial disorder. METHODS: In the present study, we performed whole-exome sequencing and co-segregation analysis in a Chinese pedigree involving two patients diagnosed with CAVD. RESULTS: We identified a rare frameshift variant (NM_000492.3: c.50dupT;p.S18Qfs*27) and a frequent CBAVD-causing variant (IVS9-TG13-5T) in both patients. The frameshift variant introduced a premature termination codon and was not found in any public databases or reported in the literature. Co-segregation analysis confirmed these two variants were in compound heterozygous state. The other male members, who harbored the frameshift variant and benign IVS9-7T allele, did not have any typical clinical manifestations of CF or CAVD. CONCLUSION: Our findings may broaden the mutation spectrum of CFTR in CAVD patients and provide more familial evidence that the combination of a mild variant and a severe variant in trans of CFTR can cause vas deferens malformation.

X-linked inheritances recessive of congenital nystagmus and autosomal dominant inheritances of congenital cataracts coexist in a Chinese family: a case report and literature review.

BACKGROUND: Congenital nystagmus (CN) and congenital cataracts are distinct eye diseases and are usually isolated. Cases with CN and congenital cataracts caused by different genes in one family have been rarely reported. CASE PRESENTATION: A 27-year-old man presented with CN and congenital cataracts and he underwent cataract extraction 2 weeks after birth. Three years later, he had posterior chamber intraocular lens implantation. The proband's mother was only afflicted by bilateral lens opacities. Lensectomy was performed in both eyes at age 15. The proband's daughter had bilateral central cataracts and no nystagmus. She had undergone cataract extraction when she was two months old. In this family, 8 affected individuals were affected by bilateral cataracts, and three of them presented with CN. The genetic analysis was performed using a specific Hereditary Ophthalmological Disease Gene Panel on proband and his parents (one of which was a patient). PCR and Sanger sequencing verified the presence of these variants in all members of the family. The novel mutation, c.498-3C > T, in FRMD7 explains why X-Linked recessive inheritance of CN was found in a subset of patients. A heterozygous mutation of the GJA8 gene (c.139G > C), was identified in all patients and thus explains the autosomal dominant pattern of inheritance of congenital cataracts within the family. CONCLUSIONS: This is the first time that FRMD7 and GJA8 gene mutations have been linked to the pathogenesis of a family with both CN and congenital cataracts. The phenomenon of two different genetic patterns coexisting in one family is rare.

A novel splice site mutation in AP1S2 gene for X-linked mental retardation in a Chinese pedigree and literature review.

BACKGROUND: Pettigrew syndrome (PGS) is a rare X-linked mental retardation that caused by AP1S2 mutation. The pathogenesis of AP1S2 deficiency has remained elusive. The purpose of this study is to give a comprehensive overview of the phenotypic and genetic spectrum of AP1S2 mutations. METHODS: This study systematically analyzed clinical features and genetic information of a Chinese family with AP1S2 variation, and reviewed previously reported literatures with the same gene variation. RESULTS: We identified a new c.1-1 G>C mutation in AP1S2 gene from a four generation family with seven affected individuals and found the elevated neuron-specific enolase (NSE) in a patient. We summarized the clinical manifestation of 59 patients with AP1S2 mutation. We found that pathogenic point mutations affecting AP1S2 are associated with dysmorphic features and neurodevelopmental problems, which included highly variable mental retardation (MR), delayed in walking, abnormal speech, hypotonia, abnormal brain, abnormal behavior including aggressive behavior, ASD, self-abusive, and abnormal gait. Patients with splice site mutation were more likely to lead to seizures. By contrast, patients with nonsense mutations are more susceptible to microcephaly. CONCLUSION: Our findings suggest AP1S2 mutations contribute to a broad spectrum of neurodevelopmental disorders and are important in the etiological spectrum of PGS.

Exome sequencing identified a novel missense mutation c.464G>A (p.G155D) in Ca2+-binding protein 4 (CABP4) in a Chinese pedigree with autosomal dominant nocturnal frontal lobe epilepsy.

The aim of this study was to identify disease-causing gene mutations in a Chinese family affected with autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE), a 4-generation pedigree of 27 members in the Southern Chinese Han population, including 11 individuals diagnosed with ADNFLE. DNA samples were collected from 15 family members, chinese han people, including seven affected and eight unaffected individuals. None of these patients had night blindness or visual disorders. Four affected individuals were screened for mutations using whole-exome sequencing, and 13 potentially interesting mutations shared by all the four affected individuals were validated using the Sanger sequencing method. Only one novel missense mutation c.464G>A (p.G155D) in the CABP4 gene, encoding the neuronal Ca2+-binding protein 4 (CaBP4), was present in all seven affected individuals in this family as revealed by PCR with blood DNA samples using CABP4 primers. The mutation was also found in one young unaffected family member, but was absent from 300 unrelated control subjects. The p.G155D mutation, located near the Ca2+ binding motif EF-hand 1 and the L-type Ca2+ channel (Cav1.4) binding motif within the N-terminal lobe of CaBP4, is predicted to affect protein function according to the bioinformatics tools PolyPhen-2 and SIFT. These findings suggest that mutations in the CABP4 gene may be linked to ADNFLE.

An LMNB1 Duplication Caused Adult-Onset Autosomal Dominant Leukodystrophy in Chinese Family: Clinical Manifestations, Neuroradiology and Genetic Diagnosis.

Autosomal dominant adult-onset demyelinating leukodystrophy (ADLD) is a very rare neurological disorder featured with late onset, slowly progressive central nervous system demyelination. Duplication or over expression of the lamin B1 (LMNB1) gene causes ADLD. In this study, we undertook a comprehensive clinical evaluation and genetic detection for a Chinese family with ADLD. The proband is a 52-year old man manifested with autonomic abnormalities, pyramidal tract dysfunction. MRI brain scan identified bilateral symmetric white matter (WM) hyper-intensities in periventricular and semi-oval WM, cerebral peduncles and middle cerebellar peduncles. The proband has a positive autosomal dominant family history with similar clinical manifestations with a trend of genetic anticipation. In order to understand the genetic cause of the disease in this family, target exome capture based next generation sequencing has been done, but no causative variants or possibly pathogenic variants has been identified. However, Multiplex ligand-dependent probe amplification (MLPA) showed whole duplication of LMNB1 gene which is co-segregated with the disease phenotype in this family. This is the first genetically confirmed LMNB1 associated ADLD pedigree from China.

CYP1B1 gene mutations with incomplete penetrance in a Chinese pedigree with primary congenital glaucoma: a case report and review of literatures.

To investigate the cytochrome P4501B1 (CYP1B1) mutations in a three-generation Chinese Han family with PCG, the 2 and 3 coding exons of CYP1B1 gene were amplified by PCR, and were directly sequenced using Sanger bidirectional sequencing reactions. The mutation c.517 G>A p.E173K was detected in all the affected individuals (which showed homozygous AA genotype) and not in all the unaffected ones except one individual. The mutation c.517 G>A p.E173K is associated with disease causing in this pedigree. And the possible genetic model is recessive inheritance. One apparently unaffected individual had mutations and haplotypes identical to her affected sibs suggested incomplete penetrance in this pedigree.

Familial gigantiform cementoma: distinctive clinical features of a large Chinese pedigree.

Familial gigantiform cementoma is a rare benign fibrocemento-osseous lesion of the jaws that can cause severe facial deformity. It has an autosomal dominant mode of inheritance, but varies in its phenotype. It is more common in white, African, and East-Asian patients. Here we report what is to our knowledge the first distinctive Chinese family with familial gigantiform cementoma involving 4 generations and 13 patients, and which suggests that the tumour presents with 3 distinctive growth phrases.