New Onset Mitral Regurgitation Caused by Mitral Valve Prolapse in a Male Patient with Dominant Pretibial Dystrophic Epidermolysis Bullosa.

Sir,

Dominant pretibial dystrophic epidermolysis bullosa (DDEB-Pt) (Online Mendelian Inheritance in Man #131850), which results from mutation of COL7A1 on chromosome 3p21 and shortened collagen VII polypeptides, is an extremely rare subtype of dystrophic epidermolysis bullosa.

A 37-year-old man presented with recalcitrant itchy papules on his shins for 12 years. Clinical examination revealed lichenoid shiny coalescing papules some with tiny excoriations [Figure 1a, b]. Transverse ridging, hyperkeratosis, lateral deviation, and greenish discoloration were observed on his bilateral great toenails [Figure 1c]. He had been repeatedly treated with topical steroids under the diagnosis of lichen planus with minimal improvement and frequent recurrence. There was no significant medical history; however, he reported sudden onset palpitations for a week. He was consulted by cardiology department. On the basis of cardiac auscultation and the findings of ecocardiography and Holter electrocardiography, mitral regurgitation caused by mitral valve prolapse and premature ventricular contractions were noted. Skin biopsy showed subepidermal cleft, chronic dermal inflammation and multiple milia [Figure 2]. Direct immunoflourescence test was negative. On the basis of the findings, as the lesions were mainly located on the shins and presence of associated nail dystrophy, the initial diagnosis of DDEB-Pt was made.

Figure 1

Lichenoid papules on pretibial skin (a), Closer view of shiny livedoid papules some with crusts and (b) Onychogryphosis of the great toe-nails (c)

Figure 2

Subepidermal clefting containing serous fluid and fibrin and edema within the adjacent dermis. Additionally, there were multiple cystic structures within the dermis, beneath the bulla. Cysts were lined by stratified squamous epithelium and contained intraluminal keratinous accumulations. (Hematoxylin-eosin stain, original magnification ×40)

To confirm the diagnosis of DDEB-Pt, a targeted next-generation sequencing panel (Qiagen, Hilden, Germany) of EB-related genes (CAST, CD151, CDSN, CSTA, CHST8, COL17A1, COL7A1, DSP, DST, EXPH 5, FERMT1, ITGA3, ITGA6, ITGB4, JUP, KLHL24, KRT14, KRT5, LAMA3, LAMB3, LAMC2, MMP1, PKP1, PLEC, SERPINB8, and TGM5) was performed on Illumina Miseq Platform. Molecular diagnosis confirmed DDEB-Pt in the patient with a heterozygous missense variation on COL7A1 (NM_000094.4) gene: c. 6082G > A (p.G2028R). This mutation has replaced in a mutational hotspot region (Triple-helical region) of the gene and has not been found any healthy population.[1]

Our patient was unique because of some aspects. Although much more commonly patients present with trauma-induced blisters, erosions, and impaired wound healing, our case of DDEB-Pt presented with gradually increasing lichenoid eruption. He was misdiagnosed as having lichen planus for a long time with subsequent inappropriate management. Because of nail bed, scarring and hyperkeratosis nail involvement is frequent in DEB. In our patient, we observed thickened, opaque, yellowish great toenail with deviation as it is called onychogryphosis. Tosti et al.[2] have reported that onychogryphosis is usually limited to the great toenails and seen in EB simplex and junctional EB.

It has been rarely reported that severe generalized DEB forms, in particular, recessive DEB (RDEB), are associated with dilated cardiomyopathy.[3] To date, the association of PT-DEB and mitral valve prolapse (MVP) has not been reported; however, MVP and aortic valvular degeneration in association with RDEB have been notified.[4] In another study mitral regurgitation as a result of myxomatous changes has been documented in RDEB.[5] Considering the fact that MVP is the most common valve abnormality in the general population with the prevalence of 3–5%, coexistence of two conditions may be incidental. On the other hand, it has been speculated that abnormality of collagen metabolism may result in valvular degeneration in patients with EB. Here, we would like to highlight a possible relationship between PT-DEB and MVP.

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Conflicts of interest

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