BACKGROUND: Although cerebral aneurysm (CA) is a defining complication of COL4A1/2-related vasculopathy, the specific factors influencing its onset remain uncertain. This study aimed to identify and analyze these factors.
METHODS: We described a family presenting with a novel variant of the COL4A1 gene complicated with CA. Concurrently, an exhaustive review of previously documented patients with COL4A1/2-related vasculopathy was conducted by sourcing data from PubMed, Web of Science, Google Scholar, and Ichushi databases. We compared the variant types and locations between patients with CA (positive group) and those without CA (negative group).
RESULTS: This study included 53 COL4A1/2 variants from 76 patients. Except for one start codon variant, all the identified variants in CA were missense variants. Otherwise, CA was not associated with other clinical manifestations, such as small-vessel disease or other large-vessel abnormalities. A higher frequency of missense variants (95.5% vs. 58.1%, p = 0.0035) was identified in the CA-positive group.
CONCLUSIONS: CA development appears to necessitate qualitative alterations in COL4A1/2, and the underlying mechanism seems independent of small-vessel disease or other large-vessel anomalies. Our findings suggest that a meticulous evaluation of CA is necessary when missense variants in COL4A1/2 are identified.

The COL4A1 (collagen Type 4 alpha1) pathogenic variant is associated with porencephaly and schizencephaly and accounts for approximately 20% of these patients. This gene variant leads to systemic microvasculopathy, which manifests as brain, ocular, renal, and muscular disorders. However, only a few patients with surgical interventions have been reported and the potential surgical risks are unknown. Here, we present the cases of two female patients between 7 and 8 years of age who were diagnosed with the COL4A1 variant and underwent laparoscopy-assisted percutaneous endoscopic gastrostomy (LAPEG) for oral dysphagia. Their primary brain lesions were caused by porencephaly and paralysis, which are caused by multiple cerebral hemorrhages and infarctions, and both patients had refractory epileptic complications. Although LAPEG was successfully performed in both patients without any intraoperative complications, one patient developed alveolar hemorrhage postoperatively and required mechanical ventilation. Thus, careful perioperative management of patients with the COL4A1 variant is important.

This report presents a case of pontine autosomal dominant microangiopathy with leukoencephalopathy (PADMAL) in a 35 year-old male patient. The patient exhibited a consistent history of recurrent ischemic strokes, concentrated primarily in the pons region, accompanied by concurrent manifestations of leukoencephalopathy and microbleeds. Genetic evaluation revealed a heterozygous missense mutation consistent with c.3431C>G, p. Thr1144Arg substitution within exon 40 of the COL4A1 gene. This mutation was also identified in the patient\'s mother, affirming an autosomal dominant inheritance model. Our findings serve as testament to the potential role of mutation in the exon 40 of COL4A1 in the pathogenesis and progression of PADMAL, contributing to ongoing efforts aimed at better understanding the genetic basis of this debilitating disorder.

BACKGROUND: Muscle cramps are a common problem characterized by a sudden, painful, and involuntary contraction of a muscle or muscle group. Most muscle cramps develop in the calf muscles, particularly in situations of prolonged exercise; however, some may be related to underlying systemic conditions such as the hereditary angiopathy with nephropathy, aneurysms, and muscle cramps (HANAC) syndrome. Muscle cramps appear to be the initial symptom of the HANAC syndrome; however, the clinical characteristics of these muscle cramps have rarely been described in detail.
METHODS: We report a familial case of autosomal-dominant muscle cramps in four members of a Japanese family spanning across three generations. The muscle cramps were recognized as systemic symptoms of the HANAC syndrome associated with a novel COL4A1 pathogenic variant, NM_001845:c.1538G > A, p.(Gly513Asp). The four affected individuals indicated that the first episodes of the muscle cramps occurred in early childhood. In addition, they reported that the muscle cramps are characterized by an abrupt onset of severe pain without muscle contraction. The painful recurrent attacks occurred spontaneously in various muscles throughout the body, but rarely in the calf muscle. The muscle pain lasts for several minutes, cannot be ameliorated by stretching the affected muscle, and leaves a feeling of discomfort that lasts for 24-48 h. The serum creatine kinase levels of the patients were persistently elevated; however, their electromyography results did not reveal any specific abnormalities.
CONCLUSIONS: Recognition of the clinical characteristics of the muscle cramps in the HANAC syndrome may facilitate early diagnosis of the syndrome and enable proper treatment of the patients, improve their long-term outcomes, and facilitate the design and adaption of appropriate genetic counseling.

UNASSIGNED: To report family members with familial retinal arteriolar tortuosity (FRAT) identified after sudden visual loss.
UNASSIGNED: A 15-year-old boy had sudden visual loss in his left eye while playing on a horizontal bar. He was referred to Nagoya City University Hospital from an eye clinic. The ophthalmologic examination showed retinal hemorrhage bilaterally. His best-corrected visual acuity (BCVA) was 20/17 in the right eye and 20/67 in the left eye. Bilateral retinal arteriolar tortuosity as well as retinal hemorrhage was seen. Since his mother with 54 years of age also had a history of retinal hemorrhage that improved spontaneously, fundus examination was performed, revealing tortuosity of the retinal arterioles. Consequently, the patient and his mother were diagnosed as FRAT. He was followed without intervention. Retinal hemorrhage gradually decreased and resolved after 3 months. The BCVA of his left eye gradually improved and reached 20/20 after 1 year.
UNASSIGNED: In this case, the family history was very useful for early diagnosis. Immediate and accurate diagnosis allowed the patient to be followed without intervention and achieve subsequent resolution of retinal hemorrhage and improved vision. FRAT should be considered in cases of sub-internal limiting membrane hemorrhages in young patients even in the presence of discrete retinal arteriolar tortuosity.

BACKGROUND: The collagen type IV alpha 1 chain (COL4A1) is an essential component of the basement membrane in small vessels. Pathogenic variants in COL4A1 cause perinatal cerebral hemorrhages in an autosomal-dominant fashion. However, little is known about the long-term outcomes of patients with mildly affecting COL4A1 mutations.
METHODS: We report a 17-year-old boy, who presented with recurrent intracranial hemorrhages in the periventricular white matter. He had been followed-up as a child with cerebral palsy bearing intracranial calcifications, developmental delay and epilepsy. Screening tests in infancy provided negative results for intrauterine infections. Severe motor and cognitive deficits persisted after admission. Carbazochrome was introduced on day 19 of admission, which appeared to prevent extension and reactivation of cerebral hemorrhages for over 6 months after discharge.
RESULTS: Targeted sequencing of NOTCH3 and TREX1 excluded causal mutations in these genes. The whole-exome sequencing revealed that he carried a de novo mutation in COL4A1 (p.Gly696Ser). An overview of the literature for 345 cases with COL4A1 mutations supported evidence that p.Gly696Ser is associated with the unique phenotype of late-onset hemorrhage among patients with COL4A1-associated cerebral angiopathy.
CONCLUSIONS: This case first demonstrates that infants with COL4A1-associated leukoencephalopathy and calcifications have a risk for developing the rupture of small vessels in the cerebral white matter after 10 years of age.

Stroke is a major cause of mortality and morbidity with a wide variety of etiological risk factors. Cerebral small vessel disease (SVD) is an important cause of stroke in the young with several hereditary disorders affecting these small blood vessels. Mutations in the COL4A1 gene (COL4A1) have been shown to be associated with a broad range of disorders including hemorrhagic stroke, myopathy, glaucoma and others. We report a rare case of stroke in an intellectually disabled 18-year-old girl with radiological evidence of basal ganglia microbleeds, periventricular white matter signal changes and porencephalic cyst. Ophthalmic examination revealed bilateral microcornea and Axenfeld-Rieger anomaly. At autopsy there were hemorrhagic lesions at multiple sites within the brain. Histology revealed thickened small-caliber vessels which demonstrated disruption and fragmentation of the basement membrane by collagen type IV alpha 1 immunohistochemistry and by electron microscopy. A missense COL4A1 mutation involving glycine residue was detected in the patient. The present case illustrates the clinicopathological spectrum of COL4A1-related cerebral SVD presenting as hemorrhagic stroke in the young with porencephaly, intellectual disability, and Axenfield-Rieger anomaly and thus adds to the clinical heterogeneity of this genetic disorder.

OBJECTIVE: To investigate the association between single nucleotide polymorphisms or haplotypes of the COL4A1 gene and the risk of intracerebral hemorrhage (ICH).
METHODS: We conducted a case-control study that included 181 patients from the Chinese Han population with hypertensive ICH and 197 hypertension patients without ICH. Genomic DNA was extracted by DNA extraction kit, and the 6 single nucleotide polymorphism genotypes of the COL4A1 gene were detected with a MassARRAY Analyzer. Unphased 3.1.4 and SPSS 19.0 were used to analyze the association between alleles, genotypes, and haplotypes of the COL4A1 gene and the risk of ICH.
RESULTS: Compared with the control group, patients in the ICH group were significantly younger. There were no differences in gender, diabetes, hyperlipidemia, current smoking, and alcohol consumption between the 2 groups. Our association analysis showed that the rs3742207 A, rs11069830 A, and rs679505 A alleles were association factors of the risks of ICH; rs11069830 AA, rs544012 AC, and rs679505 AA genotypes were association factors of the risk of ICH; AA haplotype (rs3742207-rs11069830) was an association factor of the risk of ICH. After adjusting age and gender by multivariate logistic regression, the rs544012 AC and rs679505 AA genotypes were independently associated with the risk of ICH.
CONCLUSIONS: Our study showed that the rs544012 AC and rs679505 AA genotypes were independently associated with the risk of ICH in the Chinese Han population and that the AA haplotype (rs3742207-rs11069830) in the COL4A1 gene may be related to the risk of ICH in the Chinese Han population; these conclusions need further confirmation in future studies with larger samples.

Patients with COL4A1 mutation-related disorders demonstrate a variety of disease phenotypes, which caused by small-vessel dysfunction in the brain, eyes, kidney, muscle, or heart. The involvement of organs mainly depends on the expression of the COL4A1 gene. Complication or dysfunction of the alveolar tissue has not been reported in the literature on COL4A1 mutation-related disorders. We herein report the case of a boy with schizencephaly, renovascular hypertension, and retinal arteriosclerosis of unknown origin, who suffered from severe and repetitive alveolar hemorrhage at 9 years of age. A novel COL4A1 mutation was finally identified as the genetic cause. The pulmonary complication in the present case represents an important pathophysiological mechanism COL4A1 mutation-related disorders; lung tissue with COL4A1 gene mutations may be vulnerable and environmental substances and microorganisms in the air could accumulate to cause chronic damage in the alveolar tissues, especially in patients with tracheostoma and renovascular hypertension.

With this case report, we would like to heighten the awareness of clinicians about COL4A1 as a single-gene disorder causing cerebral small vessel disease and describe a previously unreported pathogenic missense substitution in COL4A1 (p.Gly990Val) and a new clinical presentation. We identified a heterozygous putatively pathogenic mutation of COL4A1 in a 50-year-old female with a history of congenital cataracts and glaucoma who presented with multiple diffusion-positive infarcts and areas of contrast enhancement following mild head trauma. We believe that this presentation of multiple areas of acute brain and vascular injury in the setting of mild head trauma is a new manifestation of this genetic disorder. Imaging findings of multiple acute infarcts and regions of contrast enhancement with associated asymptomatic old deep microhemorrhages and leukomalacia in adults after head trauma should raise a high suspicion for a COL4A1 genetic disorder. Radiographic patterns of significant leukoaraiosis and deep microhemorrhages can also be seen in patients with long-standing vasculopathy associated with hypertension, which our patient lacked. Our findings demonstrate the utility of genetic screening for COL4A1 mutations in young patients who have small vessel vasculopathy on brain imaging but who do not have significant cardiovascular risk factors.