Browsing by Author "Krämer, Susanne"
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Publication A Novel Homozygous 9385 bp Deletion in the FERMT1 (KIND1) Gene in a Malaysian Family with Kindler Epidermolysis bullosa and a Review of Large Deletions(2025) Klausegger, Alfred; Leditzky, Fabian; Krämer, Susanne; Palisson, Francis; Yubero, María; Véliz, Sebastián; Koh, Mark; Tan, Ene-Choo; Laimer, Martin; Wolfgang, Johann; Fuentes, IgnaciaKindler Epidermolysis bullosa (KEB; OMIM 173650) is a rare autosomal recessive genodermatosis characterized by bullous poikiloderma and photosensitivity. Additional presentations include blistering, poor wound healing, skin atrophy, and increased risk of skin cancer. Most cases of KEB result from aberrations in the FERMT1 (Fermitin family member 1) gene encoding kindlin-1 and include nonsense, frameshift, splicing, and missense variants. Large deletion variants have been reported in nine cases to date. Most variants are predicted to lead to premature termination of translation and to loss of kindlin-1 function. In this study, we report on a 33-year-old male patient who presented with typical clinical manifestations of KEB. As routine molecular testing failed to obtain a diagnosis, Next Generation Sequencing (NGS) of an Epidermolysis Bullosa (EB)-specific panel was carried out followed by the determination of the deletion breakpoints and verification at the mRNA and protein levels. This approach revealed a new large homozygous deletion of ~9.4 kb in the FERMT1 gene involving exons 7 to 9. Finally, we performed a literature review on large FERMT1 deletions. The deletion is predicted to skip exons 7 to 9 within the mRNA, which results in a frameshift. The patient's phenotype is likely caused by the resulting truncated and non-functioning protein. Our report further enriches the spectrum of FERMT1 gene variants to improve genotype-phenotype correlations.Item Case Report: Crown Resorption in a Patient With Junctional Epidermolysis Bullosa and Amelogenesis Imperfecta With LAMB3 Gene Mutations(2021) Urzúa, Blanca; Krämer, Susanne; Morales-Bozo, Irene; Camacho, Claudia; Yubero, María Joao; Palisson, Francis; Fuentes, Ignacia; Ortega-Pinto, AnaBackground: Epidermolysis bullosa (EB) corresponds to a series of conditions characterized by extreme fragility of the skin and/or mucous membranes. Of the four main types of EB, junctional EB (JEB) is the most associated with alterations in the teeth. The purposes of this study were to determine the clinical, histopathological, and ultrastructural characteristics of teeth with amelogenesis imperfecta (AI) in a patient with JEB, and compare them with control teeth, and correlate the findings with the mutations present in the patient. Case Report: The study was conducted on a 10-year-old patient with JEB carrier of two recessive mutations in the LAMB3 gene and absence of the laminin-332 protein (LM-332), determined by immunofluorescence on a skin biopsy. The patient presents hypoplastic AI with very thin and yellow-brown colored enamel. Extraction of two permanent molars was performed due to pain and soft tissue covering the crown, resembling pulp polyp or hyperplastic gingiva. Light and scanning electron microscopy (SEM) revealed very thin enamel varying from complete absence to 60 μm, absence of normal prismatic structure, and presence of a cross-banding with a laminated appearance. The histopathological study revealed granulation tissue causing external crown resorption. Conclusion: Although coronary resorption has been reported in patients with syndromic and non-syndromic AI, this is the first clinicopathological report of coronary resorption in partially erupted teeth in patients with JEB with mutations in the LAMB3 gene and hypoplastic AI. In patients with this condition, the presence of partially erupted teeth with soft tissue covering part of the crown, without a periodontal pocket, and with a radiographic image of partial coronal radiolucency should lead to suspicion of external coronary resorption.Item De Novo COL7A1 mutation in a patient with trisomy 21: coexistence of dystrophic epidermolysis bullosa and Down syndrome(John Wiley & Sons, 2012) Catalán, Javiera; Rodríguez, Fernando; Yubero, María; Palisson, Francis; Gana, María; Krämer, Susanne; Repetto, GabrielaBACKGROUND: Down syndrome (DS) is the most common autosomal chromosomal disorder. Epidermolysis bullosa (EB) is a rare genodermatosis characterized by skin and mucous membrane fragility, with formation of blisters and erosions after minor trauma. Dystrophic EB (DEB) is inherited as an autosomal dominant (DDEB) or recessive (RDEB) trait. Both forms are caused by mutations in COL7A1, the gene coding for the type VII collagen. We report a patient affected by both conditions: DS and DDEB. METHODS: A patient with DS developed generalized blisters at the age of three months. Cytogenetic study was performed to confirm DS. Skin biopsies were examined with immunohistochemical and electron microscopy techniques to determine EB subtype. Genomic DNA was extracted from peripheral blood samples. COL7A1 mutations were screened by heteroduplex analysis using conformation-sensitive gel electrophoresis and sequencing. RESULTS: Karyotype analysis revealed trisomy 21. Histological study agreed with a DEB diagnosis. Mutational analysis showed a heterozygous c.6127G>T mutation in COL7A1, which is compatible with DDEB. Parental study suggests that c.6127G>T arises as a de novo mutation. CONCLUSIONS: This report demonstrates that EB can be associated with other common conditions and reports the case of a patient who suffered two de novo independent genetic conditions. It also contributes to expanding the knowledge and database of clinical and molecular aspects of DDEB.Publication Prevalence of Crown Resorption in Amelogenesis Imperfecta due to Junctional Epidermolysis Bullosa(2025) Besa, Colomba; Ortega, Ana; Véliz, Sebastián; Cornejo, Marco; Fuentes, Ignacia; Palisson, Francis; Krämer, SusanneIntroduction: Junctional epidermolysis bullosa (JEB) is a rare genetic disease manifesting with skin and mucosal blistering. As part of the JEB, patients present with syndromic amelogenesis imperfecta (AI). Reports have described external crown resorption (ECR) in the teeth of patients with JEB, but its prevalence is unknown. Objective: To determine the prevalence of ECR in patients with JEB. Methods: A longitudinal retrospective cohort study was performed at the Special Care Dentistry Clinic, University of Chile. Clinical records of patients with JEB between 2005 and 2024 were analysed. Prevalence of ECR per patient, per type of tooth and per tooth was calculated. Results: Of the 20 patients examined, 90% presented ECR in at least one tooth, with an average of 4.8 primary and 6.8 permanent teeth affected. The most affected type of teeth were the incisors. 57.5% of primary incisors and 68% of permanent incisors had resorption. The most affected tooth was #82 in primary dentition (75%) and #32 in the permanent dentition (88.9%). Conclusions: The prevalence of ECR in patients with AI due to JEB caused by variants in LAMB3 was 90%. Establishing clinical and radiographic dental protocols for the early detection of ECR is essential to prevent extensive tooth destruction.