Case of the month: a newborn with tight skin and joint contractures

Restrictive dermopathy: a rare laminopathy

BACKGROUND

Restrictive dermopathy (RD) belongs to the laminopathies and mostly shows an autosomal recessive heredity pattern. This rare genetic disorder is lethal for the newborn in the neonatal period. Clinical and pathological findings are distinctive and allow for a specific diagnosis in most cases. Furthermore, polyhydramnios, decreased foetal movement, facial dysmorphisms and arthrogryposis are characteristic of RD. Respiratory insufficiency leads to an early neonatal death.

METHODS

We present the case of an affected infant and a review of the previously reported cases in the literature.

RESULTS

The infant showed thin, shiny skin with exfoliating desquamation, a small, round and open mouth, low-set ears, a small pinched nose, joint contractures at all four extremities and distinctive pulmonic atelectasis. It died 3 h and 20 min post-partum. Histologically, the skin showed the typical pattern of an RD with the epidermis covered by an exfoliated, hyperkeratotic horn layer, clearly hypoplastic hair follicles and a considerably reduced dermis thickness, although it had a massive subcutaneous adipose tissue. Electron microscopically, the diagnosis was confirmed.

CONCLUSIONS

It is important to know about this disease and to distinguish it from others like keratinization malfunctions such as ichtyosis, congenital, developmental and akinesia disturbance, etc., to know the prognosis for the affected newborn and to provide sufficient (genetic) counselling to the families. This disorder is caused by dominant mutations of the LMNA (primary laminopathy) or recessive mutations of the ZMPSTE24 (FACE1) (secondary laminopathy) genes.

Restrictive dermopathy: report of a case and review of the literature

BACKGROUND

Restrictive dermopathy is a rare autosomal recessive skin disorder that is fatal in the neonatal period. Clinical and pathologic findings are distinctive and allow for a specific diagnosis in most cases.

METHODS

We present a case of an affected infant and a review of the previously reported cases in the literature.

RESULTS

The infant had thick shiny skin with reduced compliance and multiple spontaneous linear splits. Additional findings included an abnormal facies with a distinctive small, round and open mouth, low set ears, small nose, widely spaced sutures, flexion contractures of the extremities, and poorly expanded lungs. The infant expired 65 h after birth. Histologic findings of the skin at autopsy included a relatively unremarkable epidermis, a flat dermal-epidermal junction (absent rete ridges), an overall thinned dermis with hypoplastic appendage structures, a dense fibrotic reticular dermis with collagen parallel to the epidermis, a sharp subcutaneous margin, and an abnormally thick layer of subcutaneous adipose tissue. Electron microscopic findings included dense dermal patches of collagen and fibroblasts with abundant endoplasmic reticulum and unusually small tonofilaments. Review of previously reported cases reveals strikingly consistent findings.

CONCLUSIONS

This rare condition illustrates that abnormal cutaneous development may produce fetal hypokinesia, leading to profound effects on intrauterine growth and development. The autosomal recessive pattern of inheritance and morphologic changes of the skin and skeletal system in this disorder suggest that a structural protein or enzyme defect, perhaps of collagen metabolism, may underlie the pathogenesis.

The Tight skin mouse: demonstration of mutant fibrillin-1 production and assembly into abnormal microfibrils

Mice carrying the Tight skin (Tsk) mutation harbor a genomic duplication within the fibrillin-1 (Fbn 1) gene that results in a larger than normal in-frame Fbn 1 transcript. In this study, the consequences of the Tsk mutation for fibrillin-containing microfibrils have been examined. Dermal fibroblasts from Tsk/+ mice synthesized and secreted both normal fibrillin (approximately 330 kD) and the mutant oversized Tsk fibrillin-1 (approximately 450 kD) in comparable amounts, and Tsk fibrillin-1 was stably incorporated into cell layers. Immunohistochemical and ultrastructural analyses of normal and Tsk/+ mouse skin highlighted differences in the gross organization and distribution of microfibrillar arrays. Rotary shadowing of high Mr preparations from Tsk/+ skin demonstrated the presence of abundant beaded microfibrils. Some of these had normal morphology and periodicity, but others were distinguished by diffuse interbeads, longer periodicity, and tendency to aggregate. The presence of a structurally abnormal population of microfibrils in Tsk/+ skin was unequivocally demonstrated after calcium chelation and in denaturating conditions. Scanning transmission electron microscopy highlighted the presence of more mass in Tsk/+ skin microfibrils than in normal mice skin microfibrils. These data indicate that Tsk fibrillin-1 polymerizes and becomes incorporated into a discrete population of beaded microfibrils with altered molecular organization.