CDH3-Related Syndromes: Report on a New Mutation and Overview of the Genotype-Phenotype Correlations

The first reported case of CDH3-related hypotrichosis with juvenile macular dystrophy from Jordan: a case report

BACKGROUND

Pathogenic variants in the Cadherin 3 (CDH3) gene are responsible for the occurrence of Hypotrichosis with Juvenile Macular Dystrophy (HJMD) and Ectodermal Dysplasia, Ectrodactyly and Macular Dystrophy Syndrome (EEMS), both of which are rare autosomal recessive disorders characterized by hypotrichosis and progressive macular dystrophy. The CDH3 gene encodes for P-cadherin, a calcium-binding protein that is essential for cell-cell adhesion, which is expressed in the retinal pigment epithelial cells and hair follicles.

MATERIALS AND METHODS

Fundus examination of both eyes was done in addition to clinical investigation. Genomic DNA was extracted from a whole-blood sample and whole-exome sequencing (WES) was performed to identify the underlying etiology.All identified variants were evaluated for their pathogenicity and causality.

RESULTS

We present the first case of HJMD in a 23-year-old female patient from Jordan. The patient presented to our ophthalmology clinic with poor vision in both eyes. Gross examination revealed sparse scalp hair along with macular dystrophy on fundus exam in both eyes. HJMD was suspected and whole-exome sequencing (WES) confirmed the diagnosis with the identification of a homozygous frameshift deletion (p.Gly277AlafsTer20) localised in exon 7 of the CDH3 gene.

CONCLUSION

Blindness due to progressive macular degeneration is a common manifestation in numerous syndromic recessive disorders such as HJMD. Ophthalmologists should consider the importance of systemic manifestations and genetic testing for the confirmation of diagnosis.

The first Japanese family of CDH3-related hypotrichosis with juvenile macular dystrophy

BACKGROUND

Hypotrichosis with juvenile macular dystrophy (HJMD) is a rare autosomal recessive inherited disorder caused by biallelic variants in the CDH3 gene encoding P-cadherin. Here, we report two Japanese sibling patients with HJMD.

METHODS

Whole-exome sequencing (WES) was performed to identify disease-causing variants. In addition, ophthalmic and dermatological examinations were performed to classify the phenotype of each patient.

RESULTS

The WES analysis revealed novel compound heterozygous CDH3 variants [c.123_129dupAGGCGCG (p.Glu44fsX26) and c.2280+1G>T] in both patients; the unaffected, nonconsanguineous parents each exhibited one of the variants. Both patients showed the same clinical findings. Ophthalmologically, they exhibited progressive loss of visual acuity and chorioretinal macular atrophy, as examined with fundoscopy, fundus autofluorescence imaging, and optical coherence tomography. Full-field electroretinography, assessing generalized retinal function, revealed nearly normal amplitudes of both rod- and cone-mediated responses. Multifocal electroretinography, reflecting macular function, showed extremely decreased responses in the central area, corresponding to the chorioretinal atrophy. Dermatological examination revealed diffuse thinning of the scalp hair, which was sparse and fragile.

CONCLUSION

This is the first report of Japanese patients with HJMD and novel compound heterozygous truncating variants in CDH3. Our findings can expand the knowledge and understanding of CDH3-related HJMD, which could be helpful to ophthalmologists and dermatologists.

Sparse scalp hair and vision loss: think hypotrichosis with juvenile macular dystrophy

Here, we report the diagnostic challenge of a female patient of Russian descent with autosomal recessive hypotrichosis with juvenile macular dystrophy (HJMD). She presented to dermatology age one and a half years with sparse hair growth on her scalp, her parents were reassured this would grow, but it never manifested. She was found to be hypermetropic and prescribed glasses from age 2 but no retinal findings were noted. At age 23 years, the patient undertook an internet search and discovered the association of symptoms pointing towards HJMD. She sought genetic testing, revealing a homozygous missense mutation in Cadherin-3 (CDH3) gene. The patient presented to our Genetic Eye Disease Service at Moorfields Eye Hospital age 27 years, with reduced colour, central distance and near vision. Fundus examination and imaging confirmed atrophic macular changes. Currently, HJMD has no treatment, she wears a wig, UV-protected sunglasses in sunlight and maintains a healthy balanced diet.

Hypotrichosis with juvenile macular dystrophy: Combination of whole-genome sequencing and genome-wide homozygosity mapping identifies a large deletion in CDH3 initially undetected by whole-exome sequencing-A lesson from next-generation sequencing

BACKGROUND

Hypotrichosis with juvenile macular dystrophy (HJMD) is an autosomal recessive disorder characterized by abnormal growth of scalp hair and juvenile macular degeneration leading to blindness. We have explored the genetic basis of HJMD in a large consanguineous family with 12 affected patients, 1-76 years of age, with characteristic phenotypes.

METHODS

We first applied genome-wide homozygosity mapping to 10 affected individuals for linkage analysis to identify the genomic region of the defective gene. All affected individuals shared a 7.2 Mb region of homozygosity on chromosome 16q21-22.3, which harbored 298 genes, including CDH3, previously associated with HJMD. However, whole-exome sequencing (WES) failed to identify the causative mutation in CDH3.

RESULTS

Further investigation revealed a missense variant in a gene closely linked to CDH3 (1.4 Mb distance: FHOD1: c.1306A>G, p.Arg436Gly). This variant was homozygous in all affected individuals and heterozygous in 18 out of 19 obligate carriers. While this variant was found by bioinformatics predictions to be likely pathogenic, a knock-in mouse for this variant, made by the CRISPR/Cas, showed no disease phenotype. However, using whole-genome sequencing (WGS), we were able to identify a novel Alu recombination-mediated deletion in CDH3:c.del161-811_246 + 1,044.

CONCLUSION

WGS was able to identify a deep intronic deletion mutation, not detected by WES.

Genetic Hair Disorders: A Review

Hair loss in early childhood represents a broad differential diagnosis which can be a diagnostic and therapeutic challenge for a physician. It is important to consider the diagnosis of a genetic hair disorder. Genetic hair disorders are a large group of inherited disorders, many of which are rare. Genetic hair abnormalities in children can be an isolated phenomenon or part of genetic syndromes. Hair changes may be a significant finding or even the initial presentation of a syndrome giving a clue to the diagnosis, such as Netherton syndrome and trichothiodystrophy. Detailed history including family history and physical examination of hair and other ectodermal structures such as nails, sweat glands, and sebaceous glands with the use of dermoscopic devices and biopsy all provide important clues to establish the correct diagnosis. Understanding the pathophysiology of genetic hair defects will allow for better comprehension of their treatment and prognosis. For example, in patients with an isolated hair defect, the main problem is aesthetic. In contrast, when the hair defect is associated with a syndrome, the prognosis will depend mainly on the associated condition. Treatment of many genetic hair disorders is focused on treating the primary cause and minimizing trauma to the hair.

A unique case of vision loss in a patient with hypotrichosis and juvenile macular dystrophy and primary ciliary dyskinesia

Purpose

We describe a unique case of CDH3-related hypotrichosis with juvenile macular dystrophy (HJMD) and DNAH5-related primary ciliary dyskinesia (PCD) with progressive vision loss in a young Indian female without positive family history. Both mutations in this patient have not been previously described in the literature.

Observations

An 11-year-old girl of Indian descent from a consanguineous family presented to our clinic with poor central visual acuity, recurrent sinopulmonary infections, hypotrichosis, and gradual hearing loss. Fundus examination was significant for atrophic retinal pigmented epithelial (RPE) changes involving both the macula and periphery of both eyes with central foveal hypoautofluorescence. Optical coherence tomography (OCT) demonstrated RPE loss and significant disruption of the ellipsoid layer in both eyes. Full-field electrophysiology tests on initial presentation demonstrated low cone amplitude reduced to <70% of normal range without prolongation. OCT angiography of the RPE and choriocapillaris demonstrated possible flow voids in the central macular region of both eyes. Genetic testing showed that the proband was homozygous for variants CDH3 c.1660A > C; p. Thr554Pro and DNAH5 c.6688-1G>T.

Conclusion

and Importance: We report two novel variants in the CDH3 and DNAH5 genes that are important for future mutational analysis of both HJMD and PCD respectively. A relationship between the cadherin protein dysfunction in CDH3 mutations and the ciliopathy of DNAH5 mutations has not been established. HJMD is known to cause a longitudinal deterioration of cone and rod mediated function, therefore recognizing the symptoms, visual impairment, physical examination, and photographic and electrophysiological findings is crucial in counseling the patient, the family, and fellow clinicians.

Hypotrichosis with cone-rod dystrophy in a patient with cadherin 3 (CDH3) mutation

PURPOSE

To investigate a very rare case of hypotrichosis with cone-rod dystrophy caused by a P-cadherin CDH3 mutation.

METHODS

A 16-year-old Syrian girl was examined at age 9 and 14 years with an ophthalmological examination, fundus imaging, OCT and electrophysiological recordings (ERG and PERG). A disease-targeted gene panel sequencing was performed.

RESULTS

Fundus images showed pigmentations at the posterior eye pole to the mid periphery, as well as vessel tortuosity. OCT images revealed a loss of the outer retinal segments and IS/OS in the central macula. The scotopic and photopic ERGs showed moderately reduced amplitudes at age 9 years that became severely reduced at age of 14 years. The PERG was undetectable at age 9 years. In color vision testing, protan-deutan confusion errors occurred. Gene panel analysis revealed one homozygous mutation in CDH3 (c.1508G>A; p.Arg503His).

CONCLUSION

This case shows that a CDH3 mutation besides macula dystrophy can cause widespread cone-rod dystrophy with hypotrichosis without any other pathology besides hypoplastic nails. This points to a common pathway of hair growth and photoreceptor development that can be disturbed by a CDH3 mutation (c.1508G>A; p.Arg503His) located in the EC4 repeat region of the gene.

CDH3 gene related hypotrichosis and juvenile macular dystrophy - A case with a novel mutation

Purpose

CDH3-related hypotrichosis with juvenile macular dystrophy (HJMD) is an autosomal-recessive entity characterized by congenital sparse scalp hair and macular dystrophy, leading to severe central visual loss. We report a family with HJMD caused by a novel CDH3 gene mutation and review the mutation spectrum in HJMD. A detailed phenotypic assessment for patients whose molecular results were reported previously is also summarized.

Observations

We present a 13-year-old Turkish girl who experienced gradual bilateral visual deterioration with marked hair loss. Hair-pull test results and scalp skin texture were normal. The eyebrows and eyelashes were normal, and no abnormality in the teeth, nails, or limbs was detected. Fundus examination revealed bilateral ring-shaped atrophy of the retinal pigment epithelium with patchy intraretinal pigment clumping at the posterior pole. DNA sequencing analysis detected a novel homozygous deletion (c.447_467del (p.149_156del)) in exon 5 of the CDH3 gene of the patient. Both healthy parents and an older brother were heterozygous for the mutation.

Conclusions and importance

This case of HJMD was related to a novel homozygous mutation, termed c.447_467del (p.149_156del). These findings have significance for the future mutational analysis and genetic counseling of families with HJMD, particularly in our region. The presence of sparse hair in childhood, with or without limb anomalies, should alert clinicians to request an eye consultation. Pediatricians, dermatologists, and ophthalmologists should be aware of the rarely seen entity of juvenile macular dystrophy with hypotrichosis.

New CDH3 mutation in the first Spanish case of hypotrichosis with juvenile macular dystrophy, a case report

Background

CDH3 on 16q22.1 is responsible for two rare autosomal recessive disorders with hypotrichosis and progressive macular dystrophy: Hypotrichosis with Juvenile Macular Dystrophy and Ectodermal Dysplasia, Ectrodactyly and Macular Dystrophy. We present a new case of Hypotrichosis with Juvenile Macular Dystrophy.

Case presentation

A Spanish male born in 1998 from non-consanguineous healthy parents with a suspected diagnosis of Keratosis Follicularis Spinulosa Decalvans and Retinitis Pigmentosa Inversa referred to our Genetics Department (IIS-Fundación Jiménez Díaz).

Molecular study of ABCA4 was performed, and a heterozygous missense p.Val2050Leu variant in ABCA4 was found.

Clinical revision reclassified this patient as Hypotrichosis with Juvenile Macular Dystrophy. Therefore, further CDH3 sequencing was performed showing a novel maternal missense change p.Val205Met (probably pathogenic by in silico analysis), and a previously reported paternal frameshift c.830del;p.Gly277Alafs*20, thus supporting the clinical diagnosis..

Conclusions

This is not only the first Spanish case with this clinical and molecular diagnosis, but a new mutation has been described in CDH3. Moreover, this work reflects the importance of joint assessment of clinical signs and evaluation of pedigree for a correct genetic study approach and diagnostic.

Phenotypic observations in "hypotrichosis with juvenile macular dystrophy" (recessive CDH3 mutations)

PURPOSE

Recessive mutations in CDH3 cause "hypotrichosis with juvenile macular dystrophy," typically recognized by the presence of prominent dermatological features. We report novel phenotypic observations and associated mutations in four patients from three families, including one who did not have frank hypotrichosis.

METHODS

Retrospective case series (2010-2014).

RESULTS

Four affected individuals from three consanguineous Arabian families were identified. All four subjects (two sisters and two unrelated males; 5, 13, 17, and 26 years old) had homozygous recessive CDH3 mutations not previously associated with the condition (c.307C>T; p.R103 in two sisters, c.1859_1862delCTCT in both unrelated males). Symptomatic visual loss was since birth or early childhood. One male subject did not have frank hypotrichosis, but review of symptoms revealed relatively slow hair growth and an inability to conceive children. None had dental or digital findings, although one female noted slow nail growth. All had a circumscribed central maculopathy with borders that did not respect posterior pole horizontal arterioles (typically extending beyond the major arcades) and associated with polygonal pigment clumping. Recognition of this pattern led us to suspect the diagnosis in the male without frank hypotrichosis. Retinal dysfunction was cone-rod (rather than macular only) by ERG in one patient, who developed severe central macular atrophy and a macular hole.

CONCLUSIONS

Ophthalmologists should consider the diagnosis of CDH3-related retinopathy in individuals with such clinical features whether or not there is frank hypotrichosis.

P-cadherin and the journey to cancer metastasis

P-cadherin is a classical cell-to-cell adhesion molecule with a homeostatic function in several normal tissues. However, its behaviour in the malignant setting is notably dependent on the cellular context. In some tumour models, such as melanoma and oral squamous cell carcinoma, P-cadherin acts as a tumour suppressor, since its absence is associated with a more aggressive cancer cell phenotype; nevertheless, the overexpression of this molecule is linked to significant tumour promoting effects in the breast, ovarian, prostate, endometrial, skin, gastric, pancreas and colon neoplasms. Herein, we review the role of P-cadherin in cancer cell invasion, as well as in loco-regional and distant metastatic dissemination. We focus in P-cadherin signalling pathways that are activated to induce invasion and metastasis, as well as cancer stem cell properties. The signalling network downstream of P-cadherin is notably dependent on the cellular and tissue context and includes the activation of integrin molecules, receptor tyrosine kinases, small molecule GTPases, EMT transcription factors, and crosstalk with other cadherin family members. As new oncogenic molecular pathways mediated by P-cadherin are uncovered, putative therapeutic options can be tested, which will allow for the targeting of invasion or metastatic disease, depending on the tumour model.

The role of P-cadherin in skin biology and skin pathology: lessons from the hair follicle

Adherens junctions (AJs) are one of the major intercellular junctions in various epithelia including the epidermis and the follicular epithelium. AJs connect the cell surface to the actin cytoskeleton and comprise classic transmembrane cadherins, such as P-cadherin, armadillo family proteins, and actin microfilaments. Loss-of-function mutations in CDH3, which encodes P-cadherin, result in two allelic autosomal recessive disorders: hypotrichosis with juvenile macular dystrophy (HJMD) and ectodermal dysplasia, ectrodactyly, and macular dystrophy (EEM) syndromes. Both syndromes feature sparse hair heralding progressive macular dystrophy. EEM syndrome is characterized in addition by ectodermal and limb defects. Recent studies have demonstrated that, together with its involvement in cell-cell adhesion, P-cadherin plays a crucial role in regulating cell signaling, malignant transformation, and other major intercellular processes. Here, we review the roles of P-cadherin in skin and hair biology, with emphasize on human hair growth, cycling and pigmentation.

Clinical, genetic, and molecular aspects of split-hand/foot malformation: an update

We here provide an update on the clinical, genetic, and molecular aspects of split-hand/foot malformation (SHFM). This rare condition, affecting 1 in 8,500-25,000 newborns, is extremely complex because of its variability in clinical presentation, irregularities in its inheritance pattern, and the heterogeneity of molecular genetic alterations that can be found in affected individuals. Both syndromal and nonsyndromal forms are reviewed and the major molecular genetic alterations thus far reported in association with SHFM are discussed. This updated overview should be helpful for clinicians in their efforts to make an appropriate clinical and genetic diagnosis, provide an accurate recurrence risk assessment, and formulate a management plan.