Gomez-Lopez-Hernandez syndrome (cerebello-trigeminal-dermal dysplasia): description of an additional case and review of the literature

Co-occurrence of Gomez-Lopez-Hernandez syndrome and Autism Spectrum Disorder: Case report with review of literature

We report on Gomez-Lopez-Hernandez syndrome (GLHS) in a Caucasian patient, Georgian, 36 months, male, only child born to non-consanguineous parents. There were no similar cases in the family and among close relatives. MRI study confirmed rhombencephalosynapsis (fusion of cerebellar hemispheres in combination with the agenesis of cerebellar vermis) and mild dilation of the lateral ventricles. Other main findings are bilateral parieto-temporal alopecia and brachiturricephaly (broad skull shape and tower-like elongation of the cranium in the vertical axis), low-set posteriorly retracted ears, strabismus (in the right eye), hypotonia (Beighton scale score - 6) and ataxia (trouble maintaining balance). Patient has no signs of trigeminal anesthesia, no recurrent, painless eye infections, corneal opacities and ulcerated wounds on the facial skin and buccal mucosa were observed. Based on the scientific literature we suggest a finding of brachiturricephaly in addition to rhombencephalosynapsis and bilateral alopecia sufficient to put a diagnosis of GLHS. Patient did not speak, disregarded guardians and clinician addressing him, did not make eye contact, was restless and occasionally displayed aggression and self-injurious behavior. These symptoms confirm the earlier diagnosis of Autism Spectrum Disorder (ASD). Therefore, the current study describes a case of co-occurrence of GLHS and ASD.

Gómez-López-Hernández Syndrome: A Rare Cause of Bilateral Nonscarring Alopecia

Gómez-López-Hernández syndrome is a rare neurocutaneous disorder characterized by the triad of rhombencephalosynapsis, parietal alopecia, and trigeminal anesthesia. We report a 16-year-old girl with bilateral parietotemporal alopecia in whom cranial magnetic resonance imaging revealed rhombencephalosynapsis, suggesting a diagnosis of Gómez-López-Hernández syndrome. Neurologic examination and neuroimaging may be warranted in select patients with parietal alopecia to exclude this uncommon entity.

Gómez-López-Hernández syndrome in a Japanese patient: a case report

Gómez-López-Hernández syndrome (GLHS) is a rare neurocutaneous syndrome characterized by the triad of rhombencephalosynapsis, trigeminal anesthesia, and bilateral parieto-occipital alopecia. We herein describe the first Japanese patient with GLHS characterized by the standard triad with typical craniofacial anomaly including hypertelorism, brachyturricephaly and midface retrusion, and a short stature. This female patient had also exhibited fever-induced convulsive seizures and psychomotor developmental delay since infancy. Brain magnetic resonance imaging showed severe rhombencephalosynapsis, supratentorial abnormalities (aplasia of the septum pellucidum, severe ventricular enlargement, and hypoplasia of the corpus callosum), and hippocampus atrophy. Bilateral ectopic cerebellums were also observed. This report describes the long-term clinical outcome of GLHS and a new neuroradiological finding regarding rhombencephalosynapsis.

Gómez-López-Hernández syndrome in a child born to consanguineous parents: new evidence for an autosomal-recessive pattern of inheritance?

BACKGROUND

Gómez-López-Hernández syndrome is a rare genetic disease characterized by scalp alopecia with trigeminal anesthesia, brachycephaly or turribrachycephaly, midface retrusion, and rhombencephalosynapsis. We report the second case with this condition who presented with consanguineous parents.

PATIENT

This boy was evaluated shortly after birth because of suspected craniosynostosis. He was the only son of healthy, consanguineous parents (his maternal grandmother and his paternal great-grandfather were siblings). His examination was notable for turribrachycephaly, prominent forehead, bilateral parietotemporal alopecia, midfacial retrusion, anteverted nostrils, micrognathia, low-set and posteriorly rotated ears, and short neck with redundant skin. Radiographs and tridimensional computed tomography scan of skull revealed lambdoid craniosynostosis. Brain magnetic resonance imaging revealed complete rhombencephalosynapsis, aqueductal stenosis, fused colliculi, abnormal superior cerebellar penducle, mild ventriculomegaly, and dysgenesis of the corpus callosum.

CONCLUSIONS

Since its first description, 34 patients with this condition have been reported. The etiology of Gómez-López-Hernández syndrome is unknown. However, it is noteworthy that the patient in this report presented with a family history of consanguinity because this finding reinforces the possibility of an autosomal-recessive inheritance for this condition.

Gómez-López-hernández syndrome versus rhombencephalosynapsis spectrum: a rare co-occurrence with bipartite parietal bone

Rhombencephalosynapsis (RES) is a rare hindbrain malformation that could occur in isolation or as a part of a syndrome for example, Gómez-López-Hernández syndrome (GLH) or VACTERL-H. We identified male patient with severe RES. Ventriculomegaly, agenesis of septum pellucidum, very thin corpus callosum with interhemispheric cyst were additional neuroimaging findings. He had brachyturricephaly, midface retrusion, low-set posteriorly rotated ears and bilateral parietal well circumscribed areas of alopecia. No corneal anesthesia was observed; thus, demonstrating many of the diagnostic criteria of GLH. Interestingly, he additionally had bilateral bipartite parietal bone (BPB) that is an extremely rare anomaly of the parietal sutures. This is the first co-occurrence of this rare anomaly with GLH. We believe the presence of this unique finding could represent an important clue for understanding the pathogenesis of this malformation.

Rhombencephalosynapsis: embryopathology and management strategies of associated neurosurgical conditions with a review of the literature

OBJECT

Rhombencephalosynapsis (RS) is a rare congenital posterior fossa malformation characterized by dorsal fusion of the cerebellar hemispheres, hypogenesis or agenesis of the vermis, and fusion of the dentate nuclei and superior cerebellar peduncles. The objective of this institutional study is to review the clinical conditions associated with RS and analyze the varied biological profile of this unique condition.

METHODS

The study data were collected retrospectively from the medical records of patients at Rainbow Babies and Children's Hospital. After required institutional review board approval, the authors obtained information regarding the cases of RS reviewed by the Departments of Radiology, Genetics, and/or Pediatric Neurology. Medical charts were systematically reviewed, and 9 patients were analyzed in detail.

RESULTS

The authors describe 6 cases of RS and 3 cases of partial RS. This case series demonstrates an association between RS and symptomatic hydrocephalus (7 of 9 patients) and RS and Chiari malformation (5 of 9 patients). Patients with symptomatic hydrocephalus underwent endoscopic third ventriculostomy or ventriculoperitoneal shunt insertion. One of the patients with an associated Chiari malformation underwent foramen magnum decompression.

CONCLUSIONS

The authors present a large case series of RS. Patients with RS often had hydrocephalus and/or a Chiari Type I or II hindbrain malformation. Neuroimaging findings of RS are presented along with hypotheses to explain the embryopathology of this unusual condition.

Pluripotent stem cell model reveals essential roles for miR-450b-5p and miR-184 in embryonic corneal lineage specification

Approximately 6 million people worldwide are suffering from severe visual impairments or blindness due to corneal diseases. Corneal allogeneic transplantation is often required to restore vision; however, shortage in corneal grafts and immunorejections remain major challenges. The molecular basis of corneal diseases is poorly understood largely due to lack of appropriate cellular models. Here, we described a robust differentiation of human-induced pluripotent stem cells (hiPSCs) derived from hair follicles or skin fibroblasts into corneal epithelial-like cells. We found that BMP4, coupled with corneal fibroblast-derived conditioned medium and collagen IV allowed efficient corneal epithelial commitment of hiPSCs in a manner that recapitulated corneal epithelial lineage development with high purity. Organotypic reconstitution assays suggested the ability of these cells to stratify into a corneal-like epithelium. This model allowed us identifying miR-450b-5p as a molecular switch of Pax6, a major regulator of eye development. miR-450b-5p and Pax6 were reciprocally distributed at the presumptive epidermis and ocular surface, respectively. miR-450b-5p inhibited Pax6 expression and corneal epithelial fate in vitro, altogether, suggesting that by repressing Pax6, miR-450b-5p triggers epidermal specification of the ectoderm, while its absence allows ocular epithelial development. Additionally, miR-184 was detectable in early eye development and corneal epithelial differentiation of hiPSCs. The knockdown of miR-184 resulted in a decrease in Pax6 and K3, in line with recent findings showing that a point mutation in miR-184 leads to corneal dystrophy. Altogether, these data indicate that hiPSCs are valuable for modeling corneal development and may pave the way for future cell-based therapy.

Gómez-López-Hernández syndrome: reappraisal of the diagnostic criteria

Gómez-López-Hernández syndrome (GLHS) is a rare and possibly underdiagnosed condition. So far, 21 patients have been reported and all of them were sporadic observations. We report six additional patients. The hallmark triad of GLHS, also named cerebellotrigeminal dermal dysplasia, consists of rhombencephalosynapsis, trigeminal anesthesia (often giving rise to corneal opacities), and bilateral parietal or parieto-occipital alopecia. Our patients had rhombencephalosynapsis and alopecia, but none had trigeminal dysfunction. In this respect, the term cerebellotrigeminal dermal dysplasia is potentially misleading. In conclusion, only rhombencephalosynapsis and alopecia are consistently present in GLHS and are required diagnostic criteria, while trigeminal anesthesia, dysmorphic features, and ataxia are inconsistent findings. A high index of suspicion is required to diagnose GLHS, particularly as alopecia tends to be hidden by surrounding scalp hair.

A developmental and genetic classification for midbrain-hindbrain malformations

Advances in neuroimaging, developmental biology and molecular genetics have increased the understanding of developmental disorders affecting the midbrain and hindbrain, both as isolated anomalies and as part of larger malformation syndromes. However, the understanding of these malformations and their relationships with other malformations, within the central nervous system and in the rest of the body, remains limited. A new classification system is proposed, based wherever possible, upon embryology and genetics. Proposed categories include: (i) malformations secondary to early anteroposterior and dorsoventral patterning defects, or to misspecification of mid-hindbrain germinal zones; (ii) malformations associated with later generalized developmental disorders that significantly affect the brainstem and cerebellum (and have a pathogenesis that is at least partly understood); (iii) localized brain malformations that significantly affect the brain stem and cerebellum (pathogenesis partly or largely understood, includes local proliferation, cell specification, migration and axonal guidance); and (iv) combined hypoplasia and atrophy of putative prenatal onset degenerative disorders. Pertinent embryology is discussed and the classification is justified. This classification will prove useful for both physicians who diagnose and treat patients with these disorders and for clinical scientists who wish to understand better the perturbations of developmental processes that produce them. Importantly, both the classification and its framework remain flexible enough to be easily modified when new embryologic processes are described or new malformations discovered.

Syndromes of the first and second pharyngeal arches: A review

Our aim in this review is to discuss currently known mechanisms associated with three important syndromes of the first and second pharyngeal arches: Treacher Collins syndrome (TCS), Oculo-auriculo-vertebral syndrome (AOVS) and Auriculo-Condylar syndrome (ACS) or question mark ear syndrome. TCS and ACS are autosomal dominant diseases, with nearly complete penetrance and wide spectrum of clinical variability. The phenotype of the latter has several overlapping features with OAVS, but OAVS may exist in both sporadic and autosomal dominant forms. Mutations in the TCOF1 gene are predicted to cause premature termination codons, leading to haploinsuficiency of the protein treacle and causing TCS. Low amount of treacle leads ultimately to a reduction in the number of cranial neural crest cells migrating to the first and second pharyngeal arches. Other than TCS, the genes associated with ACS and OAVS are still unknown. The first locus for ACS was mapped by our group to 1p21-23 but there is genetic heretogeneity. Genetic heterogeneity is also present in OAVS. Based on the molecular analysis of balanced translocation in an OAVS patient, it has been suggested that abnormal expression of BAPX1 possibly due to epigenetic disregulation might be involved with the etiology of OAVS. Involvement of environmental events has also been linked to the causation of OAVS. Identification of factors leading to these disorders are important for a comprehensive delineation of the molecular pathways underlying the craniofacial development from the first and the second pharyngeal arches, for genetic counseling and to open alternative strategies for patient treatment.

Rhombencephalosynapsis and related anomalies: a neuropathological study of 40 fetal cases

Rhombencephalosynapsis is an uncommon cerebellar malformation defined by vermian agenesis with fusion of the hemispheres and of the dentate nuclei. Embryologic and genetic mechanisms are still unknown, and to date, no animal models are available. Ultrasound diagnosis is generally suspected after 22 weeks of gestation, and usually the abnormality is suggested by ventriculomegaly. Morphological analysis of 40 fetuses after medical termination of pregnancy allowed us to confirm that rhombencephalosynapsis was always associated with other brain abnormalities or malformations: Purkinje cell heterotopias, fusion of colliculi, forking and/or atresia of the aqueduct and of the third ventricle resulting in a fusion of the thalami, agenesis of the corpus callosum, lobar holoprosencephaly and neural tube defects. Pons and medulla were very infrequently abnormal. Furthermore, complete autopsy made it possible to separate either pure neurologic phenotypes, or associated with extraneural anomalies from syndromic forms: Gomez-Lopez-Hernandez syndrome (1 case) and VACTERL-H syndrome (6 cases). The number of our fetal cases strongly suggests that VACTERL-H association related with rhombencephalosynapsis emerges as a non-random association. Furthermore, recurrence and consanguinity were noted in two different families, which argue for a sporadic or inherited cause. From our results, it could be suggested that rhombencephalosynapsis may be due to defective genes regulating formation of the roof plate and the development of midline cerebellar primordium at the junction of the mesencephalon and of the first rhombomere.

Gomez-Lopez-Hernandez syndrome: two new cases and review of the literature

Gomez-Lopez-Hernandez syndrome, or cerebellotrigeminal-dermal dysplasia, is a rare neurocutaneous syndrome of trigeminal anesthesia, scalp alopecia and cerebellar anomalies. Other features include craniosynostosis, short stature, hypertelorism, down-slanting palpebral fissures, corneal opacities, mediofacial hypoplasia, and turri-brachycephaly. There have been 19 cases documented to date and we report on two additional male patients, 1 and 6 years of age, with typical features, mild mental retardation and dyspraxia. In both cases, MRI findings included rhombencephalosynapsis, a constant neuroimaging feature in this syndrome, comprising fusion of the cerebellar hemispheres with agenesis of the cerebellar vermis. Based on literature and our experience, we propose the presence of trigeminal anesthesia and/or partial alopecia of the scalp to complete the diagnosis of the syndrome.

Two new Brazilian patients with Gómez-López-Hernández syndrome: reviewing the expanded phenotype with molecular insights

Gómez-López-Hernández (GLH) syndrome or cerebello-trigeminal dysplasia is a neurocutaneous syndrome whose etiology is unknown at the present time. We report two additional Brazilian patients, including the oldest one known to date (age 29). Here, we review the expanded phenotype in four patients with new clinical, psychiatric, radiological, and molecular investigations. One patient may have hypomania within the bipolar spectrum disorder with onset in childhood and adolescence. Primary growth hormone (GH) deficiency was ruled out in all patients, although one of them might have developed secondary GH deficiency due to partial hypopituitarism following severe hydrocephalus. Brain magnetic resonance angiography disclosed no azygous anterior cerebral artery (ACA) but only normal variants. Molecular analysis of the lysosomal acid phosphatase gene (ACP2) was performed, but no pathogenic mutations were identified. We present an overview of the phenotypic features of all patients described to date. There are currently 12 unrelated patients reported in the literature, 5 of whom are Brazilian. We discuss new molecular insights and speculate about the pathogenesis of GLH syndrome.

Gomez-Lopez-Hernandez syndrome: an easily missed diagnosis

Gomez-Lopez-Hernandez syndrome (GLHS) is a rare syndrome comprising the triad rhombencephalosynapsis (RS), parietal alopecia, and trigeminal anesthesia. Other typical findings are skull abnormalities, craniofacial dysmorphic signs, and short stature. Intellectual impairment is typical but cases with normal cognitive functions have also been reported. Only 15 cases of GLHS have been described so far, all sporadic. We report four further patients with GLHS: one neonate, two children and a middle aged man. In all cases the diagnosis was made only in retrospect; one child died as neonate due to esophageal atresia. All patients presented RS and parietal alopecia, three intermittent head stereotypies, two had obvious trigeminal anesthesia, and one normal cognition. Alopecia and also trigeminal anesthesia can be very mild and can be easily missed. However, the dysmorphic signs including bilateral alopecia are already present in the neonatal period and are highly suggestive of GLHS. RS should be looked for in this situation. It is important to mention that neuroimaging does not allow distinguishing between isolated RS and GLHS. If RS is diagnosed the clinical signs of GLHS should be sought. The diagnosis of GLHS can only be made by the combination of the typical dysmorphic signs and neuroimaging in the neonatal period, but not prenatally.