Congenital hydrocephalus as a rare association with ligneous conjunctivitis and type I plasminogen deficiency

Safety and Efficacy of Long-Term Treatment of Type 1 Plasminogen Deficient Patients With Intravenous Plasminogen Replacement Therapy

INTRODUCTION

Type 1 plasminogen deficiency (PLGD-1), or hypoplasminogenaemia, is an ultra-rare autosomal-recessive disorder characterised by fibrin-rich lesions on mucous membranes, often leading to serious complications if left untreated. Prior treatments have shown limited and inconsistent success, but IV PLG concentrate (Ryplazim) offers a targeted therapy.

AIM

This study investigated the long-term safety and efficacy of IV PLG concentrate treatment for PLGD-1 patients.

METHODS

A long-term study (NCT03642691) followed 12 participants who had previously been included in pivotal or expanded access trials of IV PLG concentrate. Participants received 6.6 mg/kg IV PLG concentrate infusions, with dosing frequency adjusted based on clinical response and plasminogen levels. Safety assessments and plasminogen level measurements were conducted.

RESULTS

The median treatment duration during this long-term follow-up study was 41 months (range: 25-42 months). The median total exposure for participants in this study throughout the clinical development was 68 months (range: 28-71 months). No new or recurring ligneous lesions occurred when participants adhered to the prescribed regimen. Temporary disruptions in the drug supply led to some lesion recurrences, which resolved upon resuming the prescribed dosing frequency. A total of 2165 infusions were administered in this study, and most adverse events were mild. No anti-plasminogen antibodies or treatment-related fatalities occurred.

CONCLUSION

Long-term treatment with IV PLG concentrate is safe and effective for PLGD-1, demonstrating the potential for tailored dosing regimens. This study highlights the importance of individualised treatment and provides valuable insights into managing this ultra-rare disorder.

Loss of tissue-type plasminogen activator causes multiple developmental anomalies

Hydrocephalus and Dandy-Walker malformation are amongst the most common congenital brain anomalies. We identified three consanguineous families with both obstructive hydrocephalus and Dandy-Walker malformation. To understand the molecular basis of these anomalies, we conducted genome-wide sequencing in these families. We identified three homozygous truncating variants in the PLAT gene in the four affected family members. All of them showed tetraventricular hydrocephalus. In two individuals, a membrane at the inferior aspect of the fourth ventricle was likely the cause of their hydrocephalus. Three cases exhibited Dandy-Walker malformation, whereas the two oldest individuals displayed intellectual disability. PLAT encodes the tissue-type plasminogen activator, a serine protease whose main function is to cleave the proenzyme plasminogen to produce active plasmin. Interestingly, plasminogen deficiency has also been shown to cause obstructive hydrocephalus and Dandy-Walker malformation, suggesting that loss of PLAT causes these defects by disrupting plasmin production. In summary, we describe a recessive disorder characterized by obstructive hydrocephalus, Dandy-Walker malformation and intellectual disability in individuals with loss-of-function variants in PLAT. This discovery further strengthens the involvement of the plasminogen pathway in the pathogenesis of these developmental disorders.

Congenital hydrocephalus and ligneous conjunctivitis in two children with severe type I plasminogen deficiency: A case report and literature review

Type I plasminogen (PLG I) deficiency is a genetic disorder inherited in an autosomal recessive mode and carries high mortality and morbidity. This case report discusses two babies, aged 2 and 3 months, who were diagnosed with ligneous conjunctivitis and congenital hydrocephalus. They had progressive macrocephaly, which led to the insertion of a ventriculoperitoneal shunt. However, there was no significant improvement. During the course of the disease, they underwent genetic testing and were diagnosed with PLG I deficiency. One of the babies underwent ventriculocholecystic shunt insertion as part of palliative care and management, since this disease has poor absorption in the peritoneal cavity. Unfortunately, there was no improvement observed, and he died at 18 months. The other baby received intravenous plasma (10 ml/kg) three times a week, plus using several eye drops daily, with moderate improvement. Promising results are expected with the approved plasminogen, human-tvmh, by the Food and Drug Administration. However, access to the newly approved drug in developing countries is challenging, often hindered by cost or supply issues, necessitating the use of alternative treatments.

Plasminogen missense variants and their involvement in cardiovascular and inflammatory disease

Human plasminogen (PLG), the zymogen of the fibrinolytic protease, plasmin, is a polymorphic protein with two widely distributed codominant alleles, PLG/Asp453 and PLG/Asn453. About 15 other missense or non-synonymous single nucleotide polymorphisms (nsSNPs) of PLG show major, yet different, relative abundances in world populations. Although the existence of these relatively abundant allelic variants is generally acknowledged, they are often overlooked or assumed to be non-pathogenic. In fact, at least half of those major variants are classified as having conflicting pathogenicity, and it is unclear if they contribute to different molecular phenotypes. From those, PLG/K19E and PLG/A601T are examples of two relatively abundant PLG variants that have been associated with PLG deficiencies (PD), but their pathogenic mechanisms are unclear. On the other hand, approximately 50 rare and ultra-rare PLG missense variants have been reported to cause PD as homozygous or compound heterozygous variants, often leading to a debilitating disease known as ligneous conjunctivitis. The true abundance of PD-associated nsSNPs is unknown since they can remain undetected in heterozygous carriers. However, PD variants may also contribute to other diseases. Recently, the ultra-rare autosomal dominant PLG/K311E has been found to be causative of hereditary angioedema (HAE) with normal C1 inhibitor. Two other rare pathogenic PLG missense variants, PLG/R153G and PLG/V709E, appear to affect platelet function and lead to HAE, respectively. Herein, PLG missense variants that are abundant and/or clinically relevant due to association with disease are examined along with their world distribution. Proposed molecular mechanisms are discussed when known or can be reasonably assumed.

Plasminogen, human-tvmh for the treatment of children and adults with plasminogen deficiency type 1

AIM

An open-label phase 2/3 study of plasminogen, human-tvmh administered intravenously in paediatric and adult subjects with type 1 plasminogen deficiency was conducted. Interim data was previously reported. The final data on 15 subjects who completed the study up to a maximum of 124 weeks are reported here.

METHODS

The primary objectives were to evaluate efficacy of plasminogen replacement therapy on clinically evident or visible lesions during 48 weeks of dosing and to achieve an increase in trough plasminogen activity levels by at least an absolute 10% above baseline during 12 weeks of treatment.

RESULTS

The primary efficacy endpoint was achieved, as 100% of subjects (n = 11) with visible and assessable non-visible lesions at baseline demonstrated ≥ 50% improvement after 48 weeks of study drug treatment with plasminogen, human-tvmh. All subjects achieved the targeted ≥ 10% increase in trough plasminogen activity above baseline through Week 12. Plasminogen, human-tvmh at a dose of 6.6 mg/kg administered every 2-5 days for 48 weeks and every 1-7 days for up to 124 weeks was well tolerated.

CONCLUSION

This study provides additional evidence regarding the long-term safety and clinical utility of replacement therapy with human plasminogen for the treatment of children and adults with type 1 plasminogen deficiency. Plasminogen, human-tvmh received marketing approval on June 4, 2021. This trial was registered at www.

CLINICALTRIALS

gov as #NCT02690714.

Recurrent Meningitis and Its Rare Association With Ligneous Conjunctivitis and Congenital Plasminogen Deficiency

This case report explores the rare association of recurrent meningitis, hydrocephalus, ligneous conjunctivitis, and congenital plasminogen deficiency in a term baby boy. Born at 39 weeks with a history of hydrocephalus, the neonate later developed ligneous conjunctivitis and a serious bout of meningitis. Genetic analyses confirmed a homozygous mutation in the PLG gene, indicative of congenital plasminogen deficiency. Despite intensive treatment, including a ventriculoperitoneal shunt for hydrocephalus and intravenous antibiotics for meningitis, the child succumbed to upper airway obstruction before reaching one year of age. This report underscores the medical complexity and severity of these interconnected conditions and advocates for further research to understand the interplay between them. Although this study is limited by its single-case nature and is not generalizable, it emphasizes the necessity for early recognition and a multidisciplinary treatment approach for better patient outcomes.

A Novel mRNA Modification Mutation in a Patient With Ligneous Conjunctivitis Coexisting With Heterozygous Familial Mediterranean Fever Mutation

PURPOSE

To describe a novel mRNA mutation associated with ligneous conjunctivitis (LC) in a patient with heterozygous familial Mediterranean fever (FMF) mutation.

METHODS

Case presentation of a patient with LC and heterozygous FMF mutation. The patient was evaluated for various genetically predisposed inflammatory diseases through whole exome sequencing.

RESULTS

LC is a rare inflammatory ocular pathology presenting with recurrent conjunctivitis episodes with eosinophilic fibrin-rich pseudomembranes. FMF is an autoinflammatory disease presenting with recurrent episodes of fever, arthritis, and other inflammatory conditions. Various plasminogen (PLG) gene mutations have been identified in LC, whereas a variety of mutations in the Mediterranean fever (MEFV) gene have been identified in FMF patients. Based on the inflammatory nature of both pathologies, we aimed to evaluate and identify any potential common genetic pathway. We were not able to identify any mutation in PLG gene through whole gene sequencing; however, the patient was positive for heterozygous M680I FMF mutation, and we observed 22% of NM_000301.3:c.2130T>G (p.T710=) variant in mRNA isolated from affected tissue, which was not present in DNA sequence.

CONCLUSIONS

To the best of our knowledge, this is the first case of LC caused by an mRNA mutation coexisting with another genetically predisposed autoinflammatory disease mutation.

Treatment of plasminogen deficiency patients with fresh frozen plasma

Congenital plasminogen (Plg) deficiency leads to the development of ligneous membranes on mucosal surfaces. Here, we report our experience with local and intravenous fresh frozen plasma (FFP). We retrospectively reviewed medical files of 17 patients and their eight first-degree relatives. Conjunctivitis was the main complaint. Thirteen patients were treated both with intravenous and conjunctival FFP. Venous thrombosis did not develop in any. Genetic evaluation revealed heterogeneous mutations as well as polymorphisms. Diagnosis and treatment of Plg deficiency is challenging; topical and intravenous FFP may be an alternative treatment.

Duodenal ulceration in a patient with celiac disease and plasminogen I deficiency: coincidence or cofactors?

Celiac disease (CD) is a gluten-dependent inflammatory disease of the small bowel that affects up to 1% of the worldwide population. Despite severe mucosal abnormalities including total villous atrophy and autoantibody deposition, duodenal ulcer is not a feature of CD. However, a recent study found an elevated rate of peptic ulcer disease in patients with CD. Plasminogen deficiency (PLD) is an autosomal recessive disease that causes pseudomembranous lesions in different organs, but gastrointestinal involvement is rare. Here we report the case of a 6-year-old girl who had a sudden onset of hematemesis caused by duodenal ulcer. On the basis of mucosal atrophy, elevated celiac antibody levels, decreased plasminogen serum activity, and homozygous missense mutation R216H in the plasminogen gene, CD and PLD were diagnosed. This report is, to our knowledge, the first description of the 2 entities, and results of our double-immunofluorescent studies also suggest that both diseases may have a role in the ulceration process. Excessive amounts of fibrin deposition due to PLD caused the distortion of the vessels and was responsible for the unusual celiac immunoglobulin A and tissue transglutaminase 2 in vivo binding pattern. On the basis of this result, patients with CD and unknown cause of gastrointestinal ulcer may require investigation for PLD.

Ligneous conjunctivitis: a clinicopathological, immunohistochemical, and genetic study including the treatment of two sisters with multiorgan involvement

Ligneous conjunctivitis (LC) is a rare disease characterized by wood-like pseudomembranes developing on the ocular and extraocular mucosae secondary to plasminogen (PLG) deficiency. In this paper, we report two cases of LC in two sisters of 57 and 62 years of age that presented with recurrent, bilateral pseudomembranes on conjunctiva and a history of consanguinity and deafness. Pseudomembranes showed superficial and/or subepithelial deposits of eosinophilic amorphous hyaline, amyloid-like material with a variable proportion of granulation tissue, and inflammatory cells. The eosinophilic deposits were negative for Congo red stain, immunoreactive for fibrinogen, and consistently negative for amyloid A component, transthyretin, beta(2)-microglobulin, albumin, fibronectin, collagen type IV, vimentin, and cytokeratins. Among inflammatory cells, a percentage of positivity of roughly 60% for lymphocytes T (CD3+) and 40% for lymphocytes B (CD8+), with a relation of cytotoxic/helper (CD8/4) T cells of 3:2, was found. In one case, nasal polyps and recurrent gastric peptic ulcer were also characterized by the same subepithelial hyaline deposits. A novel homozygous point mutation c.1856 C>T was found in exon 15 of the PLG gene in both patients. Amniotic membrane transplantation was done in one case with promising results.