Alport综合征是一种以基底膜结构异常为特征的遗传性肾脏疾病，临床上表现为进行性肾功能丧失、感音神经性听力损失和各种眼部异常，由负责编码基底膜Ⅳ型胶原蛋白α3、α4和α5链的基因变异引起。尚无根治性治疗方法，药物治疗只能延缓病情进展。近年来国内外学者在Alport综合征基因治疗研究方面取得了一定的进展与收获。本文旨在从动物模型、基因转移载体、实验性基因治疗方法3个角度综述Alport综合征基因治疗的研究现状及最新进展，并讨论基因治疗可能面临的问题与挑战。.

The authors present a case of a thirty-eight-year-old patient with Alport syndrome. The patient had several ocular symptoms of the disease and has been treated for systemic problems in connection with Alport syndrome since he was fifteen years old. At that age the patient also underwent a kidney transplant in order to deal with renal insufficiency. To date, he still uses immunosuppressants and antihypertensives. Furthermore, the patient suffers from perceptive deafness. The patient visited our clinic in 2021 with a request to solve his high refractive error, in which the diopters were so high that it was not possible to place them in spectacles. The patient\'s best corrected visual acuity was 0.6 with -8.0sph/-4.0cyl/ax15 in the right eye and 0.7partim with -8.0sph/-4.0cyl/ax155 in the left eye. The autorefractometer values were -6.25sph/-6.75cyl/ax17 in the right eye and -6.75sph/-6.5cyl/ax155 in the left eye. During the eye examination we found a number of ocular manifestations that are typical of Alport syndrome. On the cornea there were opacities as a residue of corneal erosions, and at one of the following check-ups we also found a newly developed corneal erosion. Subsequently, we found an anterior lenticonus and incipient cataract. Upon performing OCT, a typical temporal macular atrophy was evident. Fundus examination in artificial mydriasis showed just a minimal manifestation of fleck retinopathy. Due to the clinical manifestation we decided to perform cataract surgery and implant a monofocal toric intraocular lens in both eyes. There were no complications during the operations, however the surgeon registered a non-standard structure of the lens capsule. The capsule was more fragile, and performing capsulorhexis was much more complicated. A week after the surgery, higher cylinder diopters were still present. A decrease of the higher diopters was noticeable one month after surgery. The time interval between the first operation and the second operation was one month. The patient was highly satisfied with result, and uncorrected visual acuity improved by over four lines. After surgery the patient needed low diopters for near as well as far distance. In the case of this patient, the ocular manifestations were detected and treated in adulthood. Nevertheless, early detection of ocular symptoms of Alport syndrome in young patients before renal failure could lead to timely start of the treatment and delay a possible renal transplant. In case of any suspicion of Alport syndrome it is advised to send the patient to a pediatrician, and at an older age to an internal medicine specialist, for further examination.

Alport Syndrome (AS) is the most common genetic glomerular disease, and it is caused by COL4A3, COL4A4, and COL4A5 pathogenic variants. The classic phenotypic spectrum associated with AS ranges from isolated hematuria to chronic kidney disease (CKD) with extrarenal abnormalities. Atypical presentation of the disorder is possible, and it can mislead the diagnosis. Polycystic kidney disease (PKD), which is most frequently associated with Autosomal Dominant PKD (ADPKD) due to PKD1 and PKD2 heterozygous variants, is emerging as a possible clinical manifestation in COL4A3-A5 patients. We describe a COL4A5 novel familial frameshift variant (NM_000495.5: c.1095dup p.(Leu366ValfsTer45)), which was associated with AS and PKD in the hemizygous proband, as well as with PKD, IgA glomerulonephritis and focal segmental glomerulosclerosis (FSGS) in the heterozygous mother. Establishing the diagnosis of AS can sometimes be difficult, especially in the context of misleading family history and atypical phenotypic features. This case study supports the emerging genotypic and phenotypic heterogeneity in COL4A3-A5-associated disorders, as well as the recently described association between PKD and collagen type IV (Col4) defects. We highlight the importance of the accurate phenotyping of all family members and the relevance of next-generation sequencing in the differential diagnosis of hereditary kidney disease.

Alport syndrome (AS) is a common and heterogeneous genetic kidney disease, that often leads to end-stage kidney disease (ESKD).
This is a single-center, retrospective study that included 36 adults with type IV collagen (COL4) mutations. Our main scope was to describe how genetic features influence renal survival.
A total of 24 different mutations were identified, of which eight had not been previously described. Mutations affecting each of the type IV collagen α chains were equally prevalent (33.3%). Most of the patients had pathogenic variants (61.1%). Most patients had a family history of kidney disease (71%). The most prevalent clinical picture was nephritic syndrome (64%). One-third of the subjects had extrarenal manifestations, 41.6% of patients had ESKD at referral, and another 8.3% developed ESKD during follow-up. The median renal survival was 42 years (95% CI, 29.98-54.01). The COL4A4 group displayed better renal survival than the COL4A3 group (p = 0.027). Patients with missense variants had higher renal survival (p = 0.023). Hearing loss was associated with lower renal survival (p < 0.001).
Patients with COL4A4 variants and those with missense mutations had significantly better renal survival, whereas those with COL4A3 variants and those with hearing loss had worse prognoses.

Alport syndrome and autosomal dominant polycystic kidney disease are monogenic causes of chronic kidney disease and end-stage kidney failure. We present a case of a man in his 60s with progressive chronic kidney disease, bilateral sensorineural hearing loss and multiple renal cysts. Genetic analysis revealed a heterozygous variant in COL4A3 (linked to Alport syndrome) and in the GANAB gene (associated with a milder form of autosomal dominant polycystic kidney disease). Although each variant confers a mild risk of developing end-stage kidney disease, the patient presented a pronounced and accelerated progression of chronic kidney disease, which goes beyond what would be predicted by adding up their individual effects. This suggests a potential synergic effect of both variants, which warrants further investigation.

BACKGROUND: Alport syndrome (AS) is characterised by haematuria, proteinuria, a gradual decline in kidney function, hearing loss, and eye abnormalities. The disease is caused by mutations in COL4An (n = 3, 4, 5) that encodes 3-5 chains of type IV collagen in the glomerular basement membrane. AS has three genetic models: X-linked, autosomal recessive, and autosomal dominant. The most common type of AS is X-linked AS, which is caused by COL4A5.
METHODS: We enrolled children with renal insufficiency and a family history of kidney disorders. The proband was identified using whole-exome sequencing. Sanger sequencing was performed to verify the mutation site. Minigene technology was used to analyse the influence of mutant genes on pre-mRNA shearing, and the Iterative Threading ASSEmbly Refinement (I-TASSER) server was used to analyse the protein structure changes.
RESULTS: The proband, together with her mother and younger brother, displayed microscopic haematuria and proteinuria, Pathological examination revealed mesangial hyperplasia and sclerosis. A novel mutation (NM_000495.5 c.4298-8G > A) in the intron of the COL4A5 gene in the proband was discovered, which was also present in the proband\'s mother, brother, and grandmother. In vitro minigene expression experiments verified that the c.4298-8G > A mutation caused abnormal splicing, leading to the retention of six base pairs at the end of intron 46. The I-TASSER software predicted that the mutation affected the hydrogen-bonding structure of COL4A5 and the electrostatic potential on the surface of the protein molecules.
CONCLUSIONS: Based on the patient\'s clinical history and genetic traits, we conclude that the mutation at the splicing site c.4298-8G > A of the COL4A5 gene is highly probable to be the underlying cause within this particular family. This discovery expands the genetic spectrum and deepens our understanding of the molecular mechanisms underlying AS.

Alport syndrome has been linked to three different genes, that is, COL4A3, COL4A4 and COL4A5. It is characterized by progressive and non-specific glomerulosclerosis with irregular thickening of the glomerular basement membrane (GBM). At times, the histopathologic picture is dominated by lesions that are consistent with focal and segmental glomerulosclerosis or IgA nephropathy. Here, we report the cases of two related individuals (mother and son) who were diagnosed with COL4A5-related Alport syndrome due to a missense variant (p.Gly1170Ser) in a G-X-Y repeat and found to present the same highly unusual histopathological abnormalities on their kidney biopsies. One of the abnormalities shared, which does not appear to have been reported, was reduced COL4A5 immunolabeling that was limited to Bowman\'s capsule even though the ultrastructure of the GBM was distorted. The other abnormality was superimposed segmental IgA deposition in both individuals, accompanied by mesangial changes in the mother. We feel that these findings provide novel insight into the mechanisms of disease manifestation in Alport syndrome. They suggest, in particular, that collagen expression and/or assemblies in Bowman\'s capsule is more vulnerable to missense mutations in COL4A5 than elsewhere in the kidney. Our findings also suggest that certain coinherited gene polymorphisms act as unexpectedly important phenotypic determinants in COL4A-related disorders.

Alport syndrome is one of the most common inherited kidney diseases caused by mutations in the type Ⅳ collagen genes. It has a complex pattern of inheritance and diverse clinical manifestations, and severe cases will rapidly progress to end-stage kidney disease. With the rapid development of genetic testing technology, there is a deeper understanding of the genetic spectrum of Alport syndrome, the effectiveness of clinical therapies, and the prediction of disease prognosis. Therefore, the purpose of the article is to introduce the advances in the diagnosis and treatment of Alport syndrome, aiming to improve the early diagnosis and standardized treatment of this disease.
Alport综合征是最常见的遗传性肾脏病之一，由Ⅳ型胶原基因突变所致，其遗传方式复杂，临床表现多样，病情重者将快速进展至终末期肾脏病。随着基因检测技术的快速发展，对Alport综合征遗传谱系、临床治疗方法的有效性以及疾病预后预测等方面有了更加深入的认识。本文旨在介绍Alport综合征的诊治最新进展，以提升其早期诊断与规范化治疗水平。.

Inherited diseases are a frequent cause of end-stage kidney disease and often seen in the kidney clinic. Clinical genomic testing is increasingly available in the UK and eligible patients in England can be referred through the NHS Genomic Medicine Service. Testing is useful for diagnosis, prognostication and management of conditions such as autosomal dominant polycystic kidney disease (ADPKD), Alport syndrome, autosomal dominant tubulointerstitial kidney disease (ADTKD) and focal segmental glomerulosclerosis (FSGS). As more patients undergo genomic testing and newer technologies such as whole genome sequencing are applied, we are developing a greater appreciation of the full phenotypic spectrum of inherited kidney diseases and the challenges associated with the interpretation of clinically significant variants.

Glomerular filtration relies on the type IV collagen (ColIV) network of the glomerular basement membrane, namely, in the triple helical molecules containing the α3, α4, and α5 chains of ColIV. Loss of function mutations in the genes encoding these chains (Col4a3, Col4a4, and Col4a5) is associated with the loss of renal function observed in Alport syndrome (AS). Precise understanding of the cellular basis for the patho-mechanism remains unknown and a specific therapy for this disease does not currently exist. Here, we generated a novel allele for the conditional deletion of Col4a3 in different glomerular cell types in mice. We found that podocytes specifically generate α3 chains in the developing glomerular basement membrane, and that its absence is sufficient to impair glomerular filtration as seen in AS. Next, we show that horizontal gene transfer, enhanced by TGFβ1 and using allogenic bone marrow-derived mesenchymal stem cells and induced pluripotent stem cells, rescues Col4a3 expression and revive kidney function in Col4a3-deficient AS mice. Our proof-of-concept study supports that horizontal gene transfer such as cell fusion enables cell-based therapy in Alport syndrome.