Early Skin Biopsy in Conradi-Hünermann-Happle Syndrome (X-Linked Dominant Chondrodysplasia Punctata)

IF 1.1 4区 医学 Q3 DERMATOLOGY
Cathal O'Connor, Neidín Bussmann, Sarah Ni Mhaolcatha, Cynthia Heffron, Sally O'Shea
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Dystrophic calcifications in keratotic follicular plugs represent a unique histopathologic feature of CHHS in newborns that has not been noted in other forms of ichthyoses [<span>3</span>]. The characteristic congenital ichthyosiform eruption clears spontaneously within a few weeks, so early biopsy is essential to capture the corresponding diagnostic histopathologic features [<span>3</span>].</p><p>We report the case of a first-born female infant who was delivered at term with widespread redness and scale. There was no family history of genodermatoses or inflammatory dermatoses. There was no parental consanguinity and no history of miscarriages. On examination, there was erythroderma, generalized thick adherent scale in a feathery pattern following lines of Blaschko, and shiny red whorls on the dorsolateral feet (Figure 1A–1F). There was no skin peeling or skin fragility. Several fingernails were hypoplastic. The nasal bridge was flat, and the neck was short. 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引用次数: 0

Abstract

Conradi-Hünermann-Happle syndrome (CHHS) or X-linked dominant chondrodysplasia punctata (CDPX2, OMIM 302960) is a rare type of chondrodysplasia punctata associated with X-linked dominant variants in the emopamil binding protein (EBP) gene, which impairs cholesterol biosynthesis [1]. The syndrome is characterized by the triad of ichthyosis (usually presenting as congenital ichthyosiform erythroderma) in 95%, skeletal dysplasia in 80%, and congenital cataracts in 60% [1]. Scarring alopecia can also be present [2]. Dystrophic calcifications in keratotic follicular plugs represent a unique histopathologic feature of CHHS in newborns that has not been noted in other forms of ichthyoses [3]. The characteristic congenital ichthyosiform eruption clears spontaneously within a few weeks, so early biopsy is essential to capture the corresponding diagnostic histopathologic features [3].

We report the case of a first-born female infant who was delivered at term with widespread redness and scale. There was no family history of genodermatoses or inflammatory dermatoses. There was no parental consanguinity and no history of miscarriages. On examination, there was erythroderma, generalized thick adherent scale in a feathery pattern following lines of Blaschko, and shiny red whorls on the dorsolateral feet (Figure 1A–1F). There was no skin peeling or skin fragility. Several fingernails were hypoplastic. The nasal bridge was flat, and the neck was short. Red reflexes were present bilaterally, but both eyes were noted to be small. The head and trunk were large relative to the limbs, and the proximal limb segments were proportionately short.

Given the constellation of signs, CHHS was suspected clinically. Skin biopsies in the first 12 h of life from linear scaly streaks showed orthohyperkeratosis and numerous dilated follicular ostia with keratin plugs (Figure 2A–2B). Foci of calcification were seen in the corneocytes of the stratum corneum and hair follicles, highlighted with a von Kossa stain (Figure 2C–2D). Skeletal survey showed symmetric punctate calcification/stippling of the proximal femoral epiphysis and ankle bilaterally and of the right humeral epiphysis and right carpus, in keeping with chondrodysplasia punctata, although no gross rhizomelia was appreciated radiologically. Ophthalmology review did not identify congenital cataracts. Renal and cranial ultrasounds were normal, and audiology was normal. Blood tests showed normal hematologic, renal, and bone parameters, and a hyperbilirubinemia meeting the phototherapy threshold. The erythema was noted to improve following 12 h of phototherapy. Urea 10% cream was helpful in reducing the scale. Single gene testing for a variant in the EBP gene was requested from blood, and a pathogenic variant was detected (c.184C>T; p.Arg62Trp), confirming the diagnosis of CHHS. Parental genetic testing for the variant was negative. On follow-up at six weeks of age, her skin had completely normalized, with no evidence of erythema or ichthyosis. Orthopedic follow-up is ongoing.

The X-linked dominant inheritance pattern of CHHS was first described by Happle in 1979 [4]. Affected unborn males are not expected to survive to birth, although there are reported cases in male patients with Klinefelter syndrome or mosaicism caused by an early postzygotic mutation in the EBP gene [5]. The cutaneous phenotype is variable and improves rapidly over the first few weeks of life, due to the effects of X-inactivation in females [6]. In neonates, it is characterized by congenital ichthyosiform erythroderma, blaschkolinear “feathery” hyperkeratosis, rhizomelia, congenital cataract(s), midface hypoplasia, and a wide flat nose. Other dermatologic manifestations may include collodion membrane, cicatricial alopecia, persistent ichthyosis, follicular atrophoderma, pigmentary abnormalities, and nail dystrophy [5].

Although the pathology of CHHS has only been reported in a few cases, typical features include hyperkeratosis and dilated ostia of the pilosebaceous units [7]. Dystrophic calcifications within keratotic infundibular follicular plugs, especially in the stratum corneum, are a unique but under-recognized histopathologic feature of newborns with CHHS [3, 7-9]. The mechanism of calcium deposition in the epidermis is unclear, although it may be related to the impact of the abnormal cholesterol on the Sonic, Desert, and Indian hedgehog pathways, which are known to be involved in both epidermal and bone homeostasis [8]. Calcium deposition on epidermal keratins is an extremely rare phenomenon and has only been reported in transepidermal elimination of calcium deposits in calcinosis cutis and in plantar corns [10].

It is important to perform the skin biopsy early, as the dystrophic calcifications typically resolve spontaneously after the first few weeks of life, in tandem with clinical resolution of the ichthyosiform erythroderma. After the ichthyosiform erythroderma has resolved, blaschkolinear hypopigmentation and follicular atrophoderma can develop. However, the distinctive dystrophic calcification will be no longer present, so later biopsy is less helpful diagnostically [1]. In this case, the clinical diagnosis was suspected immediately at birth, and the biopsy was performed in the first 12 h of life, which explains why all characteristic features were present so prototypically in the biopsy.

Other investigations to aid diagnosis in the neonatal period include sterol analysis [showing increased 8(9)-cholestenol and 8-dehydrocholesterol] in blood and genetic analysis (showing pathogenic variants in the EBP gene) [1]. The differential diagnosis for CHHS includes congenital hemidysplasia with ichthyosiform nevus and limb defects (CHILD) syndrome, another X-linked dominant disorder caused by heterozygous loss of function mutations in NSDHL, which is associated with verruciform xanthoma and inflammatory and lipid-laden infiltrates within the dermal papillae rather than intracorneal calcifications [11].

Although access to genetic testing has improved dramatically in recent years, and turnaround time has reduced significantly, the potential of early skin biopsy for histopathology to rapidly guide the diagnosis of rare genodermatoses such as CHHS in the neonatal period should not be forgotten.

Ethical approval was not applicable.

The authors declare no conflicts of interest.

Abstract Image

conradi - h nermann- apple综合征(x连锁显性点状软骨发育不良)的早期皮肤活检
conradii - h<e:2> nermann- apple综合征(CHHS)或x连锁显性点状软骨发育不良(CDPX2, OMIM 302960)是一种罕见的点状软骨发育不良类型,与emopamil结合蛋白(EBP)基因的x连锁显性变异相关,该基因会损害胆固醇的生物合成[1]。该综合征的特点是鱼鳞病(通常表现为先天性鱼鳞样红皮病)占95%,骨骼发育不良占80%,先天性白内障占60%。瘢痕性脱发也可能出现在bbb。角化性滤泡塞的营养不良钙化是新生儿CHHS的一个独特的组织病理学特征,这在其他形式的鱼鳞病中尚未被注意到。特征性的先天性鱼鳞状疹会在几周内自行清除,因此早期活检对于捕获相应的诊断组织病理学特征[3]至关重要。我们报告的情况下,第一出生的女婴谁是在足月交付与广泛的红色和规模。无遗传性皮肤病或炎症性皮肤病家族史。没有亲缘关系,也没有流产史。检查时可见红皮病,沿Blaschko线呈羽毛状的广泛性厚鳞片,足背外侧有闪亮的红色螺旋(图1A-1F)。没有皮肤脱皮或皮肤脆弱。有几个指甲发育不全。鼻梁平,脖子短。双侧均有红色反射,但双眼均小。头部和躯干相对四肢较大,近端肢节相对较短。鉴于这些体征,临床怀疑为CHHS。出生后12小时的线性鳞状条纹皮肤活检显示正角化过度和大量扩张的滤泡口伴角蛋白塞(图2A-2B)。在角质层和毛囊的角质层细胞中可见钙化灶,von Kossa染色突出显示(图2C-2D)。骨骼检查显示双侧股骨近端骨骺和踝关节以及右侧肱骨骨骺和右侧腕骨对称点状钙化/点化,与点状软骨发育不良一致,尽管放射学未发现大体根瘤。眼科检查未发现先天性白内障。肾、颅超声检查正常,听力学检查正常。血液检查显示血液学、肾脏和骨骼参数正常,高胆红素血症符合光疗阈值。光疗12小时后,红斑有所改善。尿素10%乳膏有助于减垢。要求从血液中检测EBP基因的单基因变异,检测到致病性变异(c.184C&gt;T; p.Arg62Trp),确认诊断为CHHS。该变异的亲本基因检测呈阴性。在6周大的随访中,她的皮肤完全恢复正常,没有红斑或鱼鳞病的迹象。骨科随访正在进行中。CHHS的x连锁显性遗传模式由apple于1979年首次描述。受影响的未出生男性预计无法存活到出生,尽管有报道的病例中,男性患者患有Klinefelter综合征或由EBP基因[5]的早期合子后突变引起的嵌合体。由于雌性[6]x失活的影响,皮肤表型是可变的,在生命的最初几周内迅速改善。在新生儿中,它的特征是先天性鱼鳞状红皮病、blaschkol线状“羽毛状”角化过度、根状瘤、先天性白内障、中脸发育不全和宽塌鼻。其他皮肤病表现包括胶膜、瘢痕性脱发、持续性鱼鳞病、滤泡性萎缩皮病、色素异常和指甲营养不良。虽然CHHS的病理仅在少数病例中报道,但典型的特征包括角化过度和毛囊皮脂腺单位的开口扩张。角化性漏斗滤泡塞内的营养不良钙化,尤其是角质层内的营养不良钙化,是新生儿CHHS的一个独特但未被充分认识的组织病理学特征[3,7 -9]。钙沉积在表皮的机制尚不清楚,尽管它可能与异常胆固醇对Sonic、Desert和Indian hedgehog通路的影响有关,这些通路已知参与表皮和骨稳态bbb。表皮角蛋白上的钙沉积是一种极为罕见的现象,目前仅报道过经皮清除皮肤钙质沉着症和足底角质的钙沉积。早期进行皮肤活检是很重要的,因为营养不良钙化通常在出生后几周后自发消退,与鱼鳞状红皮病的临床消退同时发生。
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来源期刊
CiteScore
3.20
自引率
5.90%
发文量
174
审稿时长
3-8 weeks
期刊介绍: Journal of Cutaneous Pathology publishes manuscripts broadly relevant to diseases of the skin and mucosae, with the aims of advancing scientific knowledge regarding dermatopathology and enhancing the communication between clinical practitioners and research scientists. Original scientific manuscripts on diagnostic and experimental cutaneous pathology are especially desirable. Timely, pertinent review articles also will be given high priority. Manuscripts based on light, fluorescence, and electron microscopy, histochemistry, immunology, molecular biology, and genetics, as well as allied sciences, are all welcome, provided their principal focus is on cutaneous pathology. Publication time will be kept as short as possible, ensuring that articles will be quickly available to all interested in this speciality.
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