Gomez?Lopez?Hernandez syndrome: another consideration in focal congenital alopecia

Prenatal diagnosis of rhombencephalosynapsis: neuroimaging features and severity of vermian anomaly

OBJECTIVES

To describe the prenatal neuroimaging spectrum of rhombencephalosynapsis (RES) and criteria for its classification according to the severity of vermian anomaly.

METHODS

In this multicenter retrospective study of fetuses with RES between 2002 and 2020, the medical records and brain ultrasound and magnetic resonance images were evaluated comprehensively to determine the severity of the vermian anomaly and the presence of associated brain findings. RES was classified, according to the pattern of vermian agenesis and the extent of the fusion of the hemispheres, as complete RES (complete absence of the vermis) or partial RES (further classified according to the part of the vermis that was missing and, consequently, the region of hemispheric fusion, as anterior, posterior, severe or mixed RES). Findings were compared between cases with complete and those with partial RES.

RESULTS

Included in the study were 62 fetuses with a gestational age ranging between 12 and 37 weeks. Most had complete absence of the vermis (complete RES, 77.4% of cases), a 'round-shaped' cerebellum on axial views (72.6%) and a transverse cerebellar diameter (TCD) < 3^rd centile (87.1%). Among the 22.6% of cases with partial RES, 6.5% were classified as severe partial, 6.5% as partial anterior, 8.1% as partial mixed and 1.6% as partial posterior. Half of these cases presented with normal or nearly normal cerebellar morphology and 28.5% had a TCD within the normal limits. Infratentorially, the fourth ventricle was abnormal in 88.7% of cases overall, and anomalies of the midbrain and pons were frequent (93.5% and 77.4%, respectively). Ventriculomegaly was observed in 80.6% of all cases, being more severe in cases with complete RES than in those with partial RES, with high rates of parenchymal and septal disruption.

CONCLUSIONS

This study provides prenatal neuroimaging criteria for the diagnosis and classification of RES, and identification of related features, using ultrasound and magnetic resonance imaging. According to our findings, a diagnosis of RES should be considered in fetuses with a small TCD (severe cerebellar hypoplasia) and/or a round-shaped cerebellum on axial views, during the second or third trimester, especially when associated with ventriculomegaly. Partial RES is more common than previously thought, but presents an extreme diagnostic challenge, especially in cases with normal or nearly-normal cerebellar morphobiometric features. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

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.

Beyond Gómez-López-Hernández syndrome: recurring phenotypic themes in rhombencephalosynapsis

Rhombencephalosynapsis (RES) is an uncommon cerebellar malformation characterized by fusion of the hemispheres without an intervening vermis. Frequently described in association with Gómez-López-Hernández syndrome, RES also occurs in conjunction with VACTERL features and with holoprosencephaly (HPE). We sought to determine the full phenotypic spectrum of RES in a large cohort of patients. Information was obtained through database review, patient questionnaire, radiographic, and morphologic assessment, and statistical analysis. We assessed 53 patients. Thirty-three had alopecia, 3 had trigeminal anesthesia, 14 had VACTERL features, and 2 had HPE with aventriculy. Specific craniofacial features were seen throughout the cohort, but were more common in patients with alopecia. We noted substantial overlap between groups. We conclude that although some distinct subgroups can be delineated, the overlapping features seen in our cohort suggest an underlying spectrum of RES-associated malformations rather than a collection of discrete syndromes.

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.

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.

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.