Retrotransposition disrupting EBP in a girl and her mother with X-linked dominant chondrodysplasia punctata.

X-linked dominant chondrodysplasia punctata (CDPX2) is a rare congenital disorder caused by pathogenic variants in EBP on Xp11.23. We encountered a girl and her mother with CDPX2-compatible phenotypes including punctiform calcification in the neonatal period of the girl, and asymmetric limb shortening and ichthyosis following the Blaschko lines in both subjects. Although Sanger direct sequencing failed to reveal a disease-causing variant in EBP, whole genome sequencing (WGS) followed by Manta analysis identified a ~ 4.5 kb insertion at EBP exon 2 of both subjects. The insertion was associated with the hallmarks of retrotransposition such as an antisense poly(A) tail, a target site duplication, and a consensus endonuclease cleavage site, and the inserted sequence harbored full-length SVA_F1 element with 5'- and 3'-transductions containing the Alu sequence. The results imply the relevance of retrotransposition to the human genetic diseases and the usefulness of WGS in the identification of retrotransposition.

Conradi-Hünermann-Happle syndrome: report of a novel heterozygous mutation on the emopamil-binding protein gene, c.333delC.

Conradi-Hünermann-Happle Syndrome, also called X-linked rhizomelic chondrodysplasia punctata, is a rare genodermatosis that presents with cutaneous, skeletal, and ophthalmological abnormalities. Herein, we report a full-term newborn that presented at birth with scattered blaschkolinear bands of adherent scales and scalp erosions in a spiral distribution. Genetic analysis of emopamil-binding protein gene revealed a previously undescribed heterozygous mutation of c.333delC.

Maternal SLE and brachytelephalangic chondrodysplasia punctata in a patient with unrelated de novo RAF1 and SIX2 variants.

Our improved tools to identify the aetiologies in patients with multiple abnormalities resulted in the finding that some patients have more than a single genetic condition and that some of the diagnoses made in the past are acquired rather than inherited. However, limited knowledge has been accumulated regarding the phenotypic outcome of the interaction between different genetic conditions identified in the same patients. We report a newborn girl with brachytelephalangic chondrodysplasia punctata (BCDP) as well as frontonasal dysplasia, ptosis, bilateral hearing loss, vertebral anomalies, and pulmonary hypoplasia who was found, by whole exome sequencing, to have a de novo pathogenic variant in RAF1 (c.770C>T, [p.Ser257Leu]) and a likely pathogenic variant in SIX2 (c.760G>A [p.A254T]), as well as maternal systemic lupus erythematosus (SLE). This case shows that BCDP is most probably not a diagnostic entity and can be associated with various conditions associated with CDP including maternal SLE.

A new case of Greenberg dysplasia and literature review suggest that Greenberg dysplasia, dappled diaphyseal dysplasia, and Astley-Kendall dysplasia are allelic disorders.

BACKGROUND: Greenberg dysplasia is a rare, autosomal recessive, prenatal lethal bone dysplasia caused by biallelic pathogenic variants in the lamin B receptor (LBR) gene. Pathogenic variants in LBR are also associated with Pelger-Huët anomaly, an autosomal dominant benign abnormality of the nuclear shape and chromatin organization of blood granulocytes, and Pelger-Huët anomaly with variable skeletal anomalies, a mild, regressing to moderate-severe autosomal recessive condition. Conditions with abnormal sterol metabolism and different genetic basis have clinical and radiographic features similar to Greenberg dysplasia, for example X-linked dominant chondrodysplasia punctata, Conradi-Hünermann type, and CHILD syndrome, and other conditions with unknown genetic etiology display very similar features, for example, dappled diaphyseal dysplasia and Astley-Kendall dysplasia. METHODS: We present a fetus with typical clinical and radiographic features of Greenberg dysplasia, and review the literature. RESULTS: Genetic testing confirmed the diagnosis Greenberg dysplasia: homozygosity for a pathogenic variant in LBR. CONCLUSION: Comparing the clinical and radiographic phenotypes of Greenberg dysplasia, dappled diaphyseal dysplasia, and Astley-Kendall dysplasia, we suggest that these are allelic disorders.

Male CDPX2 patient with EBP mosaicism and asymmetrically lateralized skin lesions with strict midline demarcation.

X-linked dominant chondrodysplasia punctata (Conradi-Hunermann-Happle syndrome, CDPX2) caused by mutations in the emopamil-binding protein (EBP) gene and congenital hemidysplasia with ichthyosiform nevus and limb defects (CHILD) syndrome caused by mutation in the NAD(P)H steroid dehydrogenase-like (NSDHL) gene are rare, typically male lethal disorders. CDPX2 skin lesions are characterized by transient severe congenital ichthyosis following the lines of Blaschko, whereas in CHILD syndrome, the lesions show striking lateralization. Here, we report a male CDPX2 patient with postzygotic mosaicism of the EBP gene presenting with lateralized skin lesions with strict midline demarcation as seen in CHILD syndrome (although this diagnosis was ruled out based on analysis of NSDHL), but also partly distributed along Blaschko's lines as seen in CDPX2. The lesions resolved within a few months, but the patient had other abnormalities, including shortening of the limbs, epiphyseal stippling, and forearm asymmetry; he also had problems with respiration and feeding in the first 4 years after birth. Kyphoscoliosis with dysplastic vertebral bodies progressed rapidly and required posterior spinal fusion surgery at 6 years old. These findings provide insights into the pathophysiology of CDPX2 and the mechanism of asymmetric lesion formation during development.

Lichenoid folliculitis of the scalp in four patients with ichthyosiform skin disorders and cicatricial alopecia.

Ichthyosis is a heterogeneous group of inherited skin disorders characterized by a defect of keratinization. Patients diagnosed with lamellar ichthyosis (LI) and some ichthyosiform syndromes, such as the Conradi-Hünermann-Happle syndrome (CHHS), usually present with hair loss. Even though only few dermatologic complaints carry as many emotional overtones as hair loss, there are very few data available in the literature regarding scalp histopathological features in ichthyosis. A better understanding of scalp changes in such context may result in new therapeutic strategies that in turn would enhance patients' self-esteem and quality of life. The aim of this paper is to describe the scalp histopathological findings of four young patients with cicatricial alopecia: three diagnosed as having LI and the fourth with CHHS.

New splicing pathogenic variant in EBP causing extreme familial variability of Conradi-Hünermann-Happle Syndrome.

X-linked dominant chondrodysplasia punctata (CDPX2 or Conradi-Hünermann-Happle syndrome, MIM #302960) is caused by mutations in the EBP gene. Affected female patients present with Blaschkolinear ichthyosis, coarse hair or alopecia, short stature, and normal psychomotor development. The disease is usually lethal in boys. Nevertheless, few male patients have been reported; they carry a somatic mosaicism in EBP or present with Klinefelter syndrome. Here, we report CDPX2 patients belonging to a three-generation family, carrying the splice variant c.301 + 5 G > C in intron 2 of EBP. The grandfather carries the variant as mosaic state and presents with short stature and mild ichthyosis. The mother also presents with short stature and mild ichthyosis and the female fetus with severe limb and vertebrae abnormalities and no skin lesions, with random X inactivation in both. This further characterizes the phenotypical spectrum of CDPX2, as well as intrafamilial variability, and raises the question of differential EBP mRNA splicing between the different target tissues.

Novel use of the Cochlear® Hybrid CI24REH cochlear implant.

Cochlear implantation is becoming more widespread. From its early days to date, huge strides have been made in the technology and surgical technique. However, one challenge remains: implanting malformed or abnormal cochleae. Even more challenging is a cochlea that appears normal at first glance, but is not. We present a case of a child with chondrodysplasia punctata, who had apparently morphologically normal inner ears, but with one major obstacle: the cochlea was smaller than normal in all dimensions. To the best of our knowledge, this is the first case described, and the solution is a novel one as well.

Chondrodysplasia Punctata: A Case Report of Fetal Warfarin Syndrome.

Chondrodysplasia punctata is abnormal calcification in the cartilage of developing bones and has been seen in association with deranged vitamin K metabolism. Warfarin, an oral anticoagulant acting on vitamin K dependent clotting factors is known to cause chondrodysplasia punctata. Despite the knowledge of the condition the management of patients with prosthetic heart valves might require use of the drug for anticoagulation. Here, we present a case of a fetal warfarin syndrome in a second born child of a 27 year lady under warfarin for prosthetic heart valve. The pregnancy was complicated by polyhydramnios in third trimester and terminated at term by normal vaginal delivery. The baby was well, except for facial dysmorphism in the form of depressed nasal bridge, narrow nares and suspected left choanal atresia. Radiograph revealed stippled ephiphysis of vertebra, femora and humera supporting diagnosis of fetal warfarin syndrome. The baby did not develop any perinatal complication and was discharged home.

Unfused Liver Segments: a Case Report of an Unknown Phenotype of the Conradi-Hünermann-Happle Syndrome.

BACKGROUND: Since its description in 1957, Couinaud`s classification of the segmental organization of the liver has remained valid. However, recent investigations by 3-dimensional computed tomography suggest a significant variability of the vascular anatomy and segment volume. Here, we report a surprise finding during the laparoscopic cholecystectomy of a patient with Conradi-Hünermann-Happle syndrome, in whom the liver segments were not fused. CASE REPORT: Laparoscopic cholecystectomy was performed because of recurrent biliary pancreatitis in a 47 year-old male patient, who had been diagnosed with Conradi-Hünermann-Happle syndrome. Upon direct view, the liver parenchyma appeared normal, but liver segments were separated and connected by fibrous bridges containing vascular structures, only. Since the hilar anatomy was unclear, an open cholecystectomy was performed without technical difficulties and the postoperative course was uneventful. Postoperatively, magnetic resonance imaging was performed, which revealed a trifurcation of the portal vein and a right bile duct draining into the left main duct. Intersegmental signal alterations corresponded to the fibrous bands seen during laparoscopy. CONCLUSIONS: The intraoperative findings of this case confirm the segmental organization of hepatic anatomy proposed by Couinaud. The first description of such an unusual anatomical variant in an extremely rare genetic disorder strongly suggests an association with the genetic background of the syndrome. The established abnormalities of cholesterol biosynthesis in patients with Conradi-Hünermann-Happle syndrome may well explain the observed liver anomaly, which is a novel phenotype of this syndrome. Based on this case, we suggest a potential involvement of the mutation in the emopamil-binding protein gene in liver development and regeneration.

Adult presentation of X-linked Conradi-Hünermann-Happle syndrome.

Conradi-Hünermann-Happle syndrome, or X-linked dominant chondrodysplasia punctata type 2 (CDPX2), is a genodermatosis caused by mutations in EBP. While typically lethal in males, females with CDPX2 generally manifest by infancy or childhood with variable features including congenital ichthyosiform erythroderma, chondrodysplasia punctata, asymmetric shortening of the long bones, and cataracts. We present a 36-year-old female with short stature, rhizomelic and asymmetric limb shortening, severe scoliosis, a sectorial cataract, and no family history of CDPX2. Whole exome sequencing (WES) revealed a p.Arg63del mutation in EBP, and biochemical studies confirmed a diagnosis of CDPX2. Short stature in combination with ichthyosis or alopecia, cataracts, and limb shortening in an adult should prompt consideration of a diagnosis of CDPX2. As in many genetic syndromes, the hallmark features of CDPX2 in pediatric patients are not readily identifiable in adults. This demonstrates the utility of WES as a diagnostic tool in the evaluation of adults with genetic disorders.

Disorders of cholesterol metabolism and their unanticipated convergent mechanisms of disease.

Cholesterol plays a key role in many cellular processes, and is generated by cells through de novo biosynthesis or acquired from exogenous sources through the uptake of low-density lipoproteins. Cholesterol biosynthesis is a complex, multienzyme-catalyzed pathway involving a series of sequentially acting enzymes. Inherited defects in genes encoding cholesterol biosynthetic enzymes or other regulators of cholesterol homeostasis result in severe metabolic diseases, many of which are rare in the general population and currently without effective therapy. Historically, these diseases have been viewed as discrete disorders, each with its own genetic cause and distinct pathogenic cascades that lead to its specific clinical features. However, studies have recently shown that three of these diseases have an unanticipated mechanistic convergence. This surprising finding is not only shedding light on details of cellular cholesterol homeostasis but also suggesting novel approaches to therapy.

The role of the abnormalities in the distal pathway of cholesterol biosynthesis in the Conradi-Hünermann-Happle syndrome.

Conradi-Hünermann-Happle syndrome (CDPX2, OMIM 302960) is an inherited X-linked dominant variant of chondrodysplasia punctata (CP) caused by mutations in one gene of the distal pathway of cholesterol biosynthesis. It exhibits intense phenotypic variation and primarily affects the skin, bones and eyes. The ichthyosis following Blaschko's lines, chondrodysplasia punctata and cataracts are the typical clinical findings. The cardinal biochemical features are an increase in 8(9)-cholestenol and 8-dehydrocholesterol (8DHC), which suggest a deficiency in 3ß-hydroxysteroid-Δ8,Δ7-isomerase, also called emopamil binding protein (EBP). The EBP gene is located on the short arm of the X chromosome (Xp11.22-p11.23) and encodes a 230 amino acid protein with dual function. Explaining the clinical phenotype in CDPX2 implies an understanding of both the genetics and biochemical features of this disease. CDPX2 displays an X-linked dominant pattern of inheritance, which is responsible for the distribution of lesions in some tissues. The clinical phenotype in CDPX2 results directly from impairment in cholesterol biosynthesis, and indirectly from abnormalities in the hedgehog signaling protein pathways. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias.

A prospective study of brachytelephalangic chondrodysplasia punctata: identification of arylsulfatase E mutations, functional analysis of novel missense alleles, and determination of potential phenocopies.

PURPOSE: The only known genetic cause of brachytelephalangic chondrodysplasia punctata is X-linked chondrodysplasia punctata 1 (CDPX1), which results from a deficiency of arylsulfatase E (ARSE). Historically, ARSE mutations have been identified in only 50% of male patients, and it was proposed that the remainder might represent phenocopies due to maternal-fetal vitamin K deficiency and maternal autoimmune diseases. METHODS: To further evaluate causes of brachytelephalangic chondrodysplasia punctata, we established a Collaboration Education and Test Translation program for CDPX1 from 2008 to 2010. Of the 29 male probands identified, 17 had ARSE mutations that included 10 novel missense alleles and one single-codon deletion. To determine pathogenicity of these and additional missense alleles, we transiently expressed them in COS cells and measured arylsulfatase E activity using the artificial substrate, 4-methylumbelliferyl sulfate. In addition, clinical data were collected to investigate maternal effects and genotype-phenotype correlations. RESULTS: In this study, 58% of males had ARSE mutations. All mutant alleles had negligible arylsulfatase E activity. There were no obvious genotype-phenotype correlations. Maternal etiologies were not reported in most patients. CONCLUSION: CDPX1 is caused by loss of arylsulfatase E activity. Around 40% of male patients with brachytelephalangic chondrodysplasia punctata do not have detectable ARSE mutations or known maternal etiological factors. Improved understanding of arylsulfatase E function is predicted to illuminate other etiologies for brachytelephalangic chondrodysplasia punctata.

Brachytelephalangic chondrodysplasia punctata: a case series to further delineate the phenotype.

Chondrodysplasia punctata (CDP) is a heterogenous group of skeletal dysplasias characterized by aberrant bone mineralization, manifesting radiologically as epiphyseal stippling. Among this group, brachytelephalangic dysplasia, a benign form of CDP (CDPX1), is probably under-reported. It is an X-linked recessive disorder and is characterized by a flat nasal tip, short columella and maxillary hypoplasia, involvement of terminal phalanges, and stippled chondrodystrophy. This paper presents a clinical series of 13 patients with brachytelephalangic dysplasia. These patients enrolled during 2002-2006 were re-evaluated and their dysmorphic features were compiled in a predesigned proforma. Skeletal survey, karyotype, cardiac evaluation, and ophthalmic evaluation were planned for all the cases. Out of 13 patients, 10 were males and three were females. All patients had flat facies, a depressed nasal bridge, a hypoplastic nose, a short philtrum, notched alae nasi, brachydactyly, and hypoplastic terminal phalanges. In addition, congenital heart disease, optic nerve hypoplasia, and developmental delay were found in a few patients. Radiography showed hypoplastic terminal phalanges, delayed bone age (1/13), epiphyseal stippling in carpal (3/13) and tarsal bones (2/13), sacral bone (1/13), and bullet-shaped lumbar vertebra (1/13). Cranial neuroimaging, thyroid profile, and karyotype carried out in a few were normal. The present paper discusses various clinical features and associated abnormalities in patients with brachytelephalangic dysplasia (CDPX1) to further delineate the phenotype. The presence of a similar phenotype in females suggests the possibility of another locus or manifestation of disease in heterozygous females. Arylsulfatase E gene analysis would further help in establishing the genotype-phenotype correlation.