Conradi-Hünermann-Happle syndrome: Clinical and trichoscopic findings.

Conradi-Hünermann-Happle syndrome (CHHS) is a rare genodermatosis resulting from mutations in the EBP (emopamil binding protein) gene. Dermatologic manifestations may include cicatricial alopecia, ichthyosis, follicular atrophoderma, pigmentary abnormalities, and nail dystrophy. In addition to genetic testing and clinical findings, trichoscopic findings may aid in the diagnosis. In this case report, we discuss the trichoscopic findings in a 3-year-old girl with CHHS and how these findings help us understand the pathophysiology of this disease.

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.

Expanding the genotypic and phenotypic landscapes of rhizomelic chondrodysplasia punctata type 3 (RCDP3) with two novel families, and a review of the literature.

Rhizomelic chondrodysplasia punctata (RCDP) are a group of peroxisomal disorders caused by plasmalogen synthesis defects. Patients with RCDP present with rhizomelic short stature, characteristic punctate epiphyseal calcifications, congenital cataracts, severe intellectual disability, seizures, and facial dysmorphism. Pathogenic variants in AGPS result in RCDP type 3 (RCDP3) which is an extremely rare disorder characterized by isolated ADHAPS deficiency. Six patients with RCDP3 have been identified, upto-date. We report two new patients with RCDP3 and their novel variants, c.154dupG (p.Ala52GlyfsTer6) and c.637+1G>A, in the AGPS gene. We also present a review of previously reported RCDP3 patients.

GGCX-related congenital combined vitamin K-dependent clotting factors deficiency-1: Description of a fetus with chondrodysplasia punctata.

Congenital combined vitamin K-dependent clotting factors deficiency (VKCFD) is a rare autosomal recessive disease resulting in hemorrhagic symptoms usually associated with developmental disorders and bone abnormalities. Pathogenic variants in two genes encoding enzymes of the vitamin K cycle, GGCX and VKORC1, can lead to this disorder. We present the case of a male fetus with a brachytelephalangic chondrodysplasia punctata (CDP), absence of nasal bone, growth restriction, and bilateral ventriculomegaly at 18 weeks of gestation. Pathological examination showed a Binder phenotype, hypoplastic distal phalanges, stippled epiphyses, and brain abnormalities suggestive of a brain hemorrhage. Two GGCX pathogenic variants inherited respectively from the mother and the father were identified. To our knowledge, this is the first prenatal description of VKCFD. Even if it remains a rare etiology, which is mostly described in children or adult patients, VKCFD should be considered in fetuses with CDP.

Conradi-Hünermann-Happle syndrome associated with severe hypocalcemia in a newborn.

Conradi-Hünermann-Happle syndrome is rare X-linked dominant syndrome associated with stippled epiphyseal calcifications, congenital cataracts, Blaschkoid ichthyosiform scaling, and follicular atrophoderma. This case describes a novel finding of hypocalcemia and hypoparathyroidism in an infant with Conradi-Hünermann-Happle syndrome.

Conradi-Hünermann-Happle syndrome with minimal signs.

A 4-year-old girl presented with congenital patches of scalp alopecia, which on physical examination, was consistent with blaschkolinear alopecic patches with mild epidermal atrophy. Similar atrophic hypopigmented patches were seen on the trunk and proximal extremities. With the clinical suspicion of Conradi-Hünermann-Happle syndrome, genetic testing was performed and revealed a mutation in the EBP gene. Despite characteristic cutaneous findings, no skeletal, ocular, or other anomalies were found on further evaluation.

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.

Genetics of Inherited Ichthyoses and Related Diseases.

Inherited ichthyoses are classified as Mendelian disorders of cornification (MEDOC), which are defined on the basis of clinical and genetic features and are mainly divided into non-syndromic and syndromic ichthyoses. Numerous genes, which encode for corresponding proteins, are involved in the normal differentiation of keratinocytes (cornification) and participate in the formation of a functional epidermal barrier. To date, mutations in more than 50 genes are known to result in various types of ichthyoses. Thanks to modern genetic diagnostic methods based on targeted next generation sequencing (NGS), approximately 80-90% of cases can be resolved at present. Further sequencing methods covering the whole exome (WES) or whole genome (WGS) will obviously elucidate another portion of the remaining unknown ichthyoses in the future.

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.

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.

Homozygous CHST11 mutation in chondrodysplasia, brachydactyly, overriding digits, clino-symphalangism and synpolydactyly.

BACKGROUND: Carbohydrate sulfotransferase 11 (CHST11) is a membrane protein of Golgi that catalyses the transfer of sulfate to position 4 of the N-acetylgalactosamine residues of chondroitin. Chondroitin sulfate is the predominant proteoglycan in cartilage, and its sulfation is important in the developing growth plate of cartilage. A homozygous deletion encompassing part of the gene and the embedded miRNA MIR3922 had been detected in a woman with hand/foot malformation and malignant lymphoproliferative disease. Chst11-deficient mouse has severe chondrodysplasia, congenital arthritis and neonatal lethality. We searched for the causative variant for the unusual combination of limb malformations with variable expressivity accompanied by skeletal defects in a consanguineous Pakistani kindred. METHODS: We performed detailed clinical investigations in family members. Homozygosity mapping using SNP genotype data was performed to map the disease locus and exome sequencing to identify the underlying molecular defect. RESULTS: The limb malformations include brachydactyly, overriding digits and clino-symphalangism in hands and feet and syndactyly and hexadactyly in feet. Skeletal defects include scoliosis, dislocated patellae and fibulae and pectus excavatum. The disease locus is mapped to a 1.6 Mb region at 12q23, harbouring a homozygous in-frame deletion of 15 nucleotides in CHST11. Novel variant c.467_481del (p.L156_N160del) is deduced to lead to the deletion of five evolutionarily highly conserved amino acids and predicted as damaging to protein by in silico analysis. Our findings confirm the crucial role of CHST11 in skeletal morphogenesis and show that CHST11 defects have variable manifestations that include a variety of limb malformations and skeletal defects.

Prenatal findings in a fetus with X-linked recessive type of chondrodysplasia punctata (CDPX1): a case report with novel mutation.

BACKGROUND: X-linked recessive chondrodysplasia punctate (CDPX1) is a rare congenital disorder of bone and cartilage development, caused by a mutation in the arylsulfatase E (ARSE) gene located on chromosome Xp22.3. Although most of the affected men had mild symptoms, some had more severe symptoms, and had a poor prognosis. CASE PRESENTATION: We present the case of a male fetus diagnosed with CDPX1. Ultrasound clearly showed that hypoplasia of the midface, flatness of face, low flatness of the nose, collapse of the tip of the nose, accompanied by severe spinal stenosis and secondary ossification center of the femoral metaphysis appeared in advance. Chromosome analysis of the amniotic fluid cells revealed 46, XY. Whole exome sequencing showed that there was a novel missense mutation of c.640G > A in ARSE gene on X chromosome. Three protein function prediction software FATHMM、Polyphen-2、PROVEAN have shown that the novel missense mutation of c.640G > A in this study was pathogenic. CONCLUSIONS: Our case is a novel mutation and presents a typical characterization of the disease, which can expand the spectrum of mutations of the ARSE gene and is helpful for prenatal ultrasound diagnosis of this disease.

[Analysis of clinical manifestation and genetic mutation in a child with X-linked chondrodysplasia punctata 2].

OBJECTIVE: To analyze clinical manifestations and genetic mutation in a child with severe short stature and other malformations. METHODS: The child has undergone history taking and physical examination. Genome DNA was extracted from peripheral blood samples of the proband and her family members. Candidate genes were captured with Agilent SureSelect and sequenced on an Illumina platform. Suspected mutation was verified by Sanger sequencing. RESULTS: The patient, a six-year-and-10-month old girl, presented with non-symmetrical short stature, dysmorphism, abnormalities of limbs and spine, amblyopia of left eye, and cataract of right eye, in addition with frequent respiratory infection and micturition. Laboratory testing suggested 25-hydroxy vitamin D deficiency (18.9 ng/mL). Spine X-ray showed multiple malformations with centrums. Her mother also featured short stature (138 cm). Her aunt had short stature (130 cm) and limb-length discrepancy. Her little brother was 2.5 years old, and his height was 81 cm (-3.4 SD). Exome sequencing revealed a heterozygous mutation c.184C to T (p.Arg62Trp) in the proband and her mother. The same mutation was not found in her father and brother. CONCLUSION: The patient was diagnosed with X-linked chondrodysplasia punctata 2. Mutation of the EBP gene probably underlied the disease in this family.

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.

Germline mosaicism is a pitfall in PGD for X-linked disorders. Single sperm typing detects very low frequency paternal gonadal mosaicism in a case of recurrent chondrodysplasia punctata misattributed to a maternal origin.

This manuscript presents a molecularly demonstrated gonadal mosaicism from paternal origin for X-linked dominant chondrodysplasia punctata by single sperm typing. A couple who had experienced two medical terminations of pregnancy of female fetuses was referred to our pre-implantation genetic diagnosis (PGD) centre with the diagnosis of maternally derived gonadal mosaicism. Indeed, genetic analyses of different DNA samples - including semen - from the healthy parents failed to detect the variant found in the fetuses. Six embryos, all male, were obtained during the PGD cycle. The causative variant was not detected in any embryo, whereas five embryos had inherited the 'at-risk' maternal haplotype. The assumption of a maternal gonadal mosaicism was still possible, but this finding allowed us to consider the possibility of a paternal rather than maternal gonadal mosaicism. It prompted us to perform extensive single sperm analyses, demonstrating a low-frequency paternal germline mosaicism, which led to completely different haplotype phasing and PGD counselling. In conclusion, this case further exemplifies that germline mosaicism is a pitfall in PGD where diagnosis largely relies on linkage analysis and suggests that tracing the parental inheritance through polar body analysis and/or single sperm typing experiments is of major importance for adequate genetic counselling and accurate PGD. © 2016 John Wiley & Sons, Ltd.

Concurrent Chondrodysplasia Punctata Type 2 (Conradi-Hunermann-Happle Syndrome) and Ichthyosis Vulgaris in Teenaged Twin Girls.

We present concurrent X-linked chondrodysplasia punctata and ichthyosis vulgaris in adolescent fraternal twin girls, notable for initial presentation with dry skin in adolescence, characterized by dark-brown scale typical of ichthyosis vulgaris and blaschkolinear, atrophic, scaly plaques. This constellation of findings prompted further genetic investigation. Using a multigene approach to examine 39 genes associated with congenital ichthyosis, next-generation sequencing revealed a novel heterozygous missense mutation at a mutational hotspot in the EBP gene c.439C>T (p.R147C) in conjunction with a single nonsense mutation in the FLG gene (p.R501X) in both sisters. These individuals highlight the clinical variability of Conradi-Hunermann-Happle syndrome, illustrate the possibility of co-occurrence of rare and common forms of ichthyosis, and demonstrate the utility of multigene analysis.

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.