Unique Variant of Cerebrotendinous Xanthomatosis Presenting With Eyelid Involvement Due to Heterozygous CYP7A1 and SLC10A1 Gene Mutations.

ABSTRACT: We report a case of a novel phenotypic variant of cerebrotendinous xanthomatosis (CTX) with an adult onset, caused by 2 coexisting mutations involving the CYP7A1 and SLC10A1 genes. A 49-year-old male patient presented with eyelid xanthomatosis associated with dermatochalasis, nystagmus, right-sided paresis with hyperreflexia and atypical parkinsonism. Bilateral xanthomatous plaques involving both Achilles tendons were subsequently detected. Histopathology of the eyelids demonstrated marked diffuse stromal infiltrates of prominent foamy histiocytes. His lipid profile showed only a slightly elevated non-high density lipoprotein cholesterol level but with normal cholesterol and cholestanol levels. By contrast, classic CTX characteristically demonstrates a markedly elevated cholestanol and a mutation involving the CYP27A1 gene for enzyme cholesterol 27-hydroxylase. Unexpectedly, molecular studies on this patient revealed a heterozygous mutation involving 2 different genes, namely, CYP7A1 and SLC10A1 genes. The CYP7A1 gene encodes for the enzyme cholesterol 7α-hydroxylase, which is a rate-limiting enzyme in the cholesterol degradation. The SLC10A1 Na+/taurocholate cotransporter gene is involved in the enterohepatic circulation of bile acids and for the hepatocyte uptake of cholesterol. We are the first to report an unusual case of an adult-onset CTX manifesting with eyelid xanthomas associated with an uncharacteristic lipid profile and a detection of novel heterozygous mutations of CYP7A1 and SLC10A1 genes in this neurocutaneous syndrome.

Whole genome sequencing identified a 16 kilobase deletion on ECA13 associated with distichiasis in Friesian horses.

BACKGROUND: Distichiasis, an ocular disorder in which aberrant cilia (eyelashes) grow from the opening of the Meibomian glands of the eyelid, has been reported in Friesian horses. These misplaced cilia can cause discomfort, chronic keratitis, and corneal ulceration, potentially impacting vision due to corneal fibrosis, or, if secondary infection occurs, may lead to loss of the eye. Friesian horses represent the vast majority of reported cases of equine distichiasis, and as the breed is known to be affected with inherited monogenic disorders, this condition was hypothesized to be a simply inherited Mendelian trait. RESULTS: A genome wide association study (GWAS) was performed using the Axiom 670 k Equine Genotyping array (MNEc670k) utilizing 14 cases and 38 controls phenotyped for distichiasis. An additive single locus mixed linear model (EMMAX) approach identified a 1.83 Mb locus on ECA5 and a 1.34 Mb locus on ECA13 that reached genome-wide significance (pcorrected = 0.016 and 0.032, respectively). Only the locus on ECA13 withstood replication testing (p = 1.6 × 10- 5, cases: n = 5 and controls: n = 37). A 371 kb run of homozygosity (ROH) on ECA13 was found in 13 of the 14 cases, providing evidence for a recessive mode of inheritance. Haplotype analysis (hapQTL) narrowed the region of association on ECA13 to 163 kb. Whole-genome sequencing data from 3 cases and 2 controls identified a 16 kb deletion within the ECA13 associated haplotype (ECA13:g.178714_195130del). Functional annotation data supports a tissue-specific regulatory role of this locus. This deletion was associated with distichiasis, as 18 of the 19 cases were homozygous (p = 4.8 × 10- 13). Genotyping the deletion in 955 horses from 54 different breeds identified the deletion in only 11 non-Friesians, all of which were carriers, suggesting that this could be causal for this Friesian disorder. CONCLUSIONS: This study identified a 16 kb deletion on ECA13 in an intergenic region that was associated with distichiasis in Friesian horses. Further functional analysis in relevant tissues from cases and controls will help to clarify the precise role of this deletion in normal and abnormal eyelash development and investigate the hypothesis of incomplete penetrance.

P63-related disorders: Dermatological characteristics in 22 patients.

In P63-related ectodermal dysplasias (ED), the clinical characteristics focus on extra-cutaneous manifestations. The dermatological phenotype remains incompletely characterized. We report the dermatological features of 22 patients carrying a TP63 mutation. Erosions, erythroderma and pigmentary anomalies are characteristics of P63-related ED. Our data suggest that patients might be classified into two major P63-related disorders: AEC and EEC. RHS and ADULT represent mild AEC and EEC forms, respectively.

Polymorphisms in P53 and VEGFA genes in different subtypes of periorbital hyperpigmentation in a Malaysian Chinese population.

BACKGROUND/OBJECTIVES: The unknown pathogenesis of periorbital hyperpigmentation makes its treatment difficult. Existing evidence links p53 and VEGFA genes with skin hyperpigmentation. This study was aimed at (i) identifying the clinical pattern of periorbital hyperpigmentation; and (ii) detecting the presence of VEGFA and P53 single nucleotide polymorphism (SNPs) in different subtypes of periorbital hyperpigmentation in Malaysian Chinese. METHODS: A cross-sectional study was conducted among Malaysian Chinese. Clinical assessments were performed, and medical history was collected. Three regions of p53 and two of VEGFA were amplified by PCR followed by direct sequencing using saliva-extracted DNA. RESULTS: Eighty-four participants were recruited (average age 22.2 years). In the majority (n = 62), both eyelids were affected. Facial pigmentary, demarcation lines, tear trough and eye bags were not observed. Mixed (pigmented-vascular) was the most common subtype. Thirteen SNPs were found, nine of which are new. Only three out of 13 SNPs showed significant association with periorbital hyperpigmentation presentation. TA genotype in rs1437756379 (p53) was significantly more prevalent among participants with mixed subtype (P = 0.011) while AC genotype in rs1377053612 (VEGFA) was significantly more prevalent among pigmented subtype (P = 0.028). AA genotype in rs1479430148 (VEGFA) was significantly associated with allergic rhinitis in mixed subtype (P = 0.012). CONCLUSION: Mixed subtype was the most prevalent type of periorbital hyperpigmentation in the study population. Three polymorphisms in p53 and VEGFA genes were statistically linked with different clinical presentations of periorbital hyperpigmentation.

Compensatory increases in tear volume and mucin levels associated with meibomian gland dysfunction caused by stearoyl-CoA desaturase-1 deficiency.

The stearoyl-CoA desaturase (SCD) family of enzymes catalyzes monounsaturated fatty acid synthesis by inserting a cis double bond at the Δ9 position of saturated fatty acids. Disruption of these enzymes has been reported to induce a severe dry skin phenotype. Since lipid abnormalities in the meibomian glands have been associated with dry eye, we analyzed selected eye tissues contributing to tear volume and composition in genetically SCD-1-deficient mice (SCD-1 KO), including the lacrimal glands and conjunctiva. Previous histopathological analysis had revealed atrophy and loss of meibomian glands; taken together with the increased goblet cell and MUC5AC expression in the conjunctiva reported here, these findings suggest that the tear volume and mucin levels secreted are enhanced in the absence of lipid secretion as a compensatory mechanism. The expression of lipid metabolism genes in lacrimal glands was decreased in SCD1 KO mice. Thus, these results provide new pathophysiological mechanisms to pursue with regard to meibomian gland dysfunction. In addition, lack of SCD-1 causes a compensatory increase in the tear volume and mucin levels associated with changes in expression of lipid metabolism genes. These results may be useful as a new concept for dry eye treatment strategies.

Clinical Description, Molecular Analysis of TWIST2 Gene, and Surgical Treatment in a Patient With Barber-Say Syndrome.

Barber-Say syndrome is a rare autosomal dominant disease characterized by dysmorphic features, mainly of the eyelids and skin. It is caused by heterozygous mutations in gene TWIST2, localized in chromosome 2q37.3. The authors present the case of a pediatric patient with a clinical diagnosis of Barber-Say syndrome with ocular symptoms related to exposure keratitis. Molecular analysis of her DNA revealed a mutation on TWIST2 gene confirming the diagnosis of Barber-Say syndrome. Surgical treatment of the patient's eyelids resolved her signs and symptoms.

Confirmation that RIPK4 mutations cause not only Bartsocas-Papas syndrome but also CHAND syndrome.

CHAND syndrome is an autosomal recessive disorder characterized by curly hair, ankyloblepharon, and nail dysplasia. Only few patients were reported to date. A homozygous RIPK4 mutation was recently identified by homozygosity mapping and whole exome sequencing in three patients from an expanded consanguineous kindred with a clinical diagnosis of CHAND syndrome. RIPK4 was previously known to be implicated in Bartsocas-Papas syndrome, the autosomal recessive form of popliteal pterygium syndrome. We report here two cases of RIPK4 homozygous mutations in a fetus with severe Bartsocas-Papas syndrome and a patient with CHAND syndrome. The patient with CHAND syndrome harbored the same mutation as the one identified in the family previously reported. We thus confirm the implication of RIPK4 gene in CHAND syndrome in addition to Bartsocas-Papas syndrome and discuss genotype/phenotype correlations.

A γA-Crystallin Mouse Mutant Secc with Small Eye, Cataract and Closed Eyelid.

Cataract is the most common cause of visual loss in humans. A spontaneously occurred, autosomal dominant mouse mutant Secc, which displayed combined features of small eye, cataract and closed eyelid was discovered in our laboratory. In this study, we identified the mutation and characterized the cataract phenotype of this novel Secc mutant. The Secc mutant mice have eyelids that remain half-closed throughout their life. The mutant lens has a significant reduction in size and with opaque spots clustered in the centre. Histological analysis showed that in the core region of the mutant lens, the fiber cells were disorganized and clefts and vacuoles were observed. The cataract phenotype was evident from new born stage. We identified the Secc mutation by linkage analysis using whole genome microsatellite markers and SNP markers. The Secc locus was mapped at chromosome 1 flanked by SNPs rs3158129 and rs13475900. Based on the chromosomal position, the candidate cataract locus γ-crystallin gene cluster (Cryg) was investigated by sequencing. A single base deletion (299delG) in exon 3 of Cryga which led to a frame-shift of amino acid sequence from position 91 was identified. As a result of this mutation, the sequences of the 3rd and 4th Greek-key motifs of the γA-crystallin are replaced with an unrelated C-terminal peptide of 75 residues long. Coincidentally, the point mutation generated a HindIII restriction site, allowing the identification of the CrygaSecc mutant allele by RFLP. Western blot analysis of 3-week old lenses showed that the expression of γ-crystallins was reduced in the CrygaSecc mutant. Furthermore, in cell transfection assays using CrygaSecc mutant cDNA expression constructs in 293T, COS-7 and human lens epithelial B3 cell lines, the mutant γA-crystallins were enriched in the insoluble fractions and appeared as insoluble aggregates in the transfected cells. In conclusion, we have demonstrated that the Secc mutation leads to the generation of CrygaSecc proteins with reduced solubility and prone to form aggregates within lens cells. Accumulation of mutant proteins in the lens fibers would lead to cataract formation in the Secc mutant.

Barber-Say syndrome and Ablepharon-Macrostomia syndrome: An overview.

Barber-Say syndrome (BSS) and Ablepharon-Macrostomia syndrome (AMS) are congenital malformation syndromes caused by heterozygous mutations in TWIST2. Here we provide a critical review of all patients published with these syndromes. We excluded several earlier reports due to misdiagnosis or insufficient data for reliable confirmation of the diagnosis. There remain 16 reliably diagnosed individuals with BSS and 16 with AMS. Major facial characteristics present in both entities, albeit often in differing frequencies, are excessive facial creases, hypertelorism, underdevelopment of the anterior part of the eyelids (anterior lamella), ectropion, broad nasal ridge and tip, thick and flaring alae nasi, protruding maxilla, wide mouth, thin upper vermillion, and attached ear lobes. In BSS a remarkable extension of the columella on the philtrum can be seen, and in both the medial parts of the cheeks bulge towards the corners of the mouth (cheek pads). Scalp hair is sparse in AMS only, but sparse eyebrows and eyelashes occur in both entities, and general hypertrichosis occurs in BSS. We compare these characteristics with those in Setleis syndrome which can also be caused by TWIST2 mutations. The resemblance between the three syndromes is considerable, and likely differences seem larger than they actually are due to insufficiently complete evaluation for all characteristics of the three entities in the past. It is likely that with time it can be concluded that BSS. AMS and Setleis syndrome form a continuum. © 2016 Wiley Periodicals, Inc.

Notch Signaling in Meibomian Gland Epithelial Cell Differentiation.

PURPOSE: Notch1 was previously shown to play a critical role in murine meibomian gland function and maintenance. In this study, we have examined the expression and activation of Notch pathway in human meibomian gland epithelial cells in vitro. METHODS: An immortalized human meibomian gland epithelial cell (HMGEC) line was cultured under proliferative and differentiative conditions. Expression of Notch receptors and ligands were evaluated by quantitative PCR and Western blot. The effect of Notch inhibition and induction on oil production was also assessed. RESULTS: Human meibomian gland epithelial cell expressed Notch1, Notch2, Notch3, Jagged1, Jagged2, Delta-like 1, and Delta-like 3. The level of cleaved (activated) Notch1 strongly increased with differentiation. The expression of Notch3 was inversely correlated with proliferation. Induction and inhibition of Notch1 led to an increase and decrease in the amount of oil production, respectively. CONCLUSIONS: Notch signaling appears to play an important role in human meibomian gland epithelial differentiation and oil production. This may provide a potential therapeutic pathway for treating meibomian gland dysfunction.

Meibomian Gland Absence Related Dry Eye in Ectodysplasin A Mutant Mice.

Meibomian gland dysfunction is the most frequent cause of evaporative dry eye, yet its underlying pathophysiology is unknown. To gain insight into this pathophysiology, we characterized the time-dependent tear film and ocular surface changes occurring in X-linked anhidrotic-hypohidrotic ectodermal dysplasia mice (Tabby), which lack the meibomian gland. These mice sequentially developed corneal epithelial defects, central corneal stromal edema, neovascularization, and pannus 8 to 16 weeks after birth. Aqueous tear secretion was normal, whereas tear break-up time and ex vivo tear evaporation times were all shortened. Corneal epithelial microvilli were less numerous, conjunctival goblet cell density was unaffected, and MUC5AC and MUC5B gene expression was increased. Markers of squamous metaplasia (cytokeratin 10 and small proline-rich protein 1B) were noticed in the corneal epithelium of Tabby mice as early as the fourth week. Taken together, the Tabby mouse is a relevant meibomian gland dysfunction-related dry eye model that may lead to a better understanding of how meibomian glands are related to ocular surface health. This model may also help with discovering novel drug options for treating evaporative dry eye.

Elevation deficiency in children with recessive RDH12-related retinopathy.

Children with retinal dystrophies often have nonspecific strabismus, but vertical incomitant deviations are uncommon. We report 4 children from 3 consanguineous families with bilateral elevation deficiency in the context of retinal dystrophy. All were found to harbor recessive mutations in retinal dehydrogenase 12 (RDH12).

Identification of a novel mutation in RIPK4 in a kindred with phenotypic features of Bartsocas-Papas and CHAND syndromes.

Three children from an expanded consanguineous Kuwaiti kindred presented with ankyloblepharon, sparse and curly hair, and hypoplastic nails, suggestive of CHAND syndrome (OMIM 214350) that belongs to the heterogeneous spectrum of ectodermal dysplasias. After exclusion of pathogenic mutations in TP63 we performed homozygosity mapping, followed by exome sequencing of one affected individual. We initially identified three homozygous mutations in the linked region, located in PWP2, MX2 and RIPK4. Recently, mutations in RIPK4 have been reported in Bartsocas-Papas syndrome (OMIM 263650) that shows overlapping clinical symptoms with the phenotype observed in the affected individuals studied here. Subsequent analysis of affected and non-affected family members showed that mutation c.850G>A (p.Glu284Lys) in RIPK4 was in complete segregation with the disease phenotype, in accordance with an autosomal recessive inheritance pattern, thus supporting pathogenicity of this variant. Interestingly, however, our patients did not have cleft lip/palate, a common feature encountered in Bartsocas-Papas syndrome. Whereas in Bartsocas-Papas syndromes missense mutations are usually located within the serin/threonin kinase of RIPK4, the mutation detected in our family resides just outside of the kinase domain, which could explain the milder phenotype. Our data raise the question if CHAND syndrome indeed is a distinct entity. Alternatively, CHAND and Bartsocas-Papas syndrome might be allelic disorders or RIPK4 mutations could confer varying degrees of phenotypic severity, depending on their localization within or outside functionally important domains. Our findings indicate that making an accurate diagnosis based only on the prevailing clinical symptoms is challenging.

Recurrent Mutations in the Basic Domain of TWIST2 Cause Ablepharon Macrostomia and Barber-Say Syndromes.

Ablepharon macrostomia syndrome (AMS) and Barber-Say syndrome (BSS) are rare congenital ectodermal dysplasias characterized by similar clinical features. To establish the genetic basis of AMS and BSS, we performed extensive clinical phenotyping, whole exome and candidate gene sequencing, and functional validations. We identified a recurrent de novo mutation in TWIST2 in seven independent AMS-affected families, as well as another recurrent de novo mutation affecting the same amino acid in ten independent BSS-affected families. Moreover, a genotype-phenotype correlation was observed, because the two syndromes differed based solely upon the nature of the substituting amino acid: a lysine at TWIST2 residue 75 resulted in AMS, whereas a glutamine or alanine yielded BSS. TWIST2 encodes a basic helix-loop-helix transcription factor that regulates the development of mesenchymal tissues. All identified mutations fell in the basic domain of TWIST2 and altered the DNA-binding pattern of Flag-TWIST2 in HeLa cells. Comparison of wild-type and mutant TWIST2 expressed in zebrafish identified abnormal developmental phenotypes and widespread transcriptome changes. Our results suggest that autosomal-dominant TWIST2 mutations cause AMS or BSS by inducing protean effects on the transcription factor's DNA binding.

Familial Moniliform Blepharosis: Clinical, Histopathological and Genetic Correlation.

BACKGROUND: Moniliform blepharosis is an ocular diagnostic feature of lipoid proteinosis, a rare autosomal recessive multisystem disorder with dermatological, otorhinolaryngological, ocular and neurological manifestations. Loss of function mutations in the extracellular matrix protein 1 (ECM1) gene have been identified as the causative factor, and their identification confirms the diagnosis. Until now, 41 different mutations have been described, the majority being nonsense and small insertions. Exon 6 and 7 are the most commonly involved. MATERIALS AND METHODS: Case report of an 8-year-old girl who presented with bilateral waxy papular lesions on the margins of the upper and lower lids since the age of 2 years. RESULTS: Biopsy of the eyelid lesions showed replacement of the sub-epidermal space by pink, PAS-positive and diastase resistant hyalinized material. Genetic testing of theECM1 gene showed a homozygous nonsense mutation c.1441C > T (p.Arg481X) in exon 10, confirming the diagnosis of lipoid proteinosis. CONCLUSIONS: Ophthalmologists may be the first physicians to encounter patients with lipoid proteinosis. The disease presents with protean symptoms, hence a careful examination with histopathology and genetic mutation analysis confirms the diagnosis, assisting in the counseling and management of patients.

Granular corneal dystrophy type 2 is associated with morphological abnormalities of meibomian glands.

AIMS: To investigate morphological changes in meibomian glands in patients with granular corneal dystrophy type 2 (GCD2) using non-invasive meibography. METHODS: Eleven patients (3 men and 8 women) with GCD2, and sex-matched and age-matched healthy volunteers as a controls were enrolled in this study. The diagnosis of GCD2 was confirmed by transforming growth factor ß-induced (TGFBI) gene analysis using direct sequencing in exon 4 of TGFBI gene. Meibography was performed in the right eye of the studied cases. Meiboscore was determined according to the morphology of meibomian gland and classified into four grades; grade 0 (no meibomian gland loss), grade 1 (loss less than one-third the total area of meibomian glands), grade 2 (area loss between one-third and two-thirds of the total area), and grade 3 (area loss greater than two-thirds of the total). RESULTS: R124H mutation was detected in all patients with GCD2. Extinguishing or shortening of the meibomian glands was observed in patients with GCD2. The meiboscore was 3.8±1.3 in patients with GCD2 and 1.3±1.1 in the control group, showing significant difference between two groups (Mann-Whitney U-test, p=0.042). CONCLUSIONS: In GCD2, corneal deposits, and also morphological abnormalities of meibomian glands, such as obstruction or shortening, were found. Since abnormal phospholipid deposition is noted in GCD2, these results are interesting because phospholipid is possibly secreted from the meibomian gland.