Pontine hypoplasia in 5p-syndrome: A key MRI finding for a diagnosis

Prenatal Diagnosis of 5p Deletion Syndrome with Brain Abnormalities by Ultrasonography and Fetal Magnetic Resonance Imaging: A Case Report

Introduction: 5p deletion syndrome commonly known as cri du chat syndrome is a well-described syndrome in neonates with catlike cry, craniofacial dysmorphic features, abnormal dermatoglyphics, microcephaly and severe psychomotor and developmental delay.Case report: We report a case of 5p deletion syndrome diagnosed prenatally in association with mild ventriculomegaly, cerebellar hypoplasia, pontine hypoplasia, increased subarachnoid space and high suspicion of cortical hypoplasia with ultrasound, magnetic resonance imaging, and postmortem examination.Conclusion: Best to our knowledge, this is the first case that pontine hypoplasia and increased subarachnoid space have been demonstrated prenatally and confirmed by postnatal autopsy.

Structural brain anomalies in Cri-du-Chat syndrome: MRI findings in 14 patients and possible genotype-phenotype correlations

INTRODUCTION

Cri-du-Chat Syndrome (CdCS) is a genetic condition due to deletions showing different breakpoints encompassing a critical region on the short arm of chromosome 5, located between p15.2 and p15.3, first defined by Niebuhr in 1978. The classic phenotype includes a characteristic cry, peculiar facies, microcephaly, growth retardation, hypotonia, speech and psychomotor delay and intellectual disability. A wide spectrum of clinical manifestations can be attributed to differences in size and localization of the 5p deletion. Several critical regions related to some of the main features (such as cry, peculiar facies, developmental delay) have been identified. The aim of this study is to further define the genotype-phenotype correlations in CdCS with particular regards to the specific neuroradiological findings.

PATIENTS AND METHODS

Fourteen patients with 5p deletions have been included in the present study. Neuroimaging studies were conducted using brain Magnetic Resonance Imaging (MRI). Genetic testing was performed by means of comparative genomic hybridization (CGH) array at 130 kb resolution.

RESULTS

MRI analyses showed that isolated pontine hypoplasia is the most common finding, followed by vermian hypoplasia, ventricular anomalies, abnormal basal angle, widening of cavum sellae, increased signal of white matter, corpus callosum anomalies, and anomalies of cortical development. Chromosomal microarray analysis identified deletions ranging in size from 11,6 to 33,8 Mb on the short arm of chromosome 5. Then, we took into consideration the overlapping and non-overlapping deleted regions. The goal was to establish a correlation between the deleted segments and the neuroradiological features of our patients.

CONCLUSIONS

Performing MRI on all the patients in our cohort, allowed us to expand the neuroradiological phenotype in CdCS. Moreover, possible critical regions associated to characteristic MRI findings have been identified.

Children and adults affected by Cri du Chat syndrome: Care's recommendations

Our objective is to collect data and information for a better care and follow up in Cri du Chat patients. We conducted a literature review in August 2017 and then discuss the outcomes within the ABC (Associazione Bambini Cri du Chat, Italian CdC families support group). A proposal for clinical, laboratory and imaging work up should be performed at various ages in CdC patients. Follow up and rehabilitation should continue lifelong as some improvements can be obtained also in older ages and not to lose acquired skills.

Brain stem hypoplasia associated with Cri-du-Chat syndrome

Cri-du-Chat syndrome, also called the 5p-syndrome, is a rare genetic abnormality, and only few cases have been reported on its brain MRI findings. We describe the magnetic resonance imaging findings of a 1-year-old girl with Cri-du-Chat syndrome who showed brain stem hypoplasia, particularly in the pons, with normal cerebellum and diffuse hypoplasia of the cerebral hemispheres. We suggest that Cri-du-Chat syndrome chould be suspected in children with brain stem hypoplasia, particularly for those with high-pitched cries.

Clinical and radiological features of Japanese patients with a severe phenotype due to CASK mutations

Heterozygous loss of function mutations of CASK at Xp11.4 in females cause severe intellectual disability (ID) and microcephaly with pontine and cerebellar hypoplasia (MICPCH). However, the longitudinal clinical and radiological course of affected patients, including patterns of postnatal growth, has not been described. Neurodevelopmental and imaging information was retrospectively accrued for 16 Japanese (15 female and 1 male) patients with ID and MICPCH associated with CASK mutations. All records were analyzed; patient age ranged from 2 to 16 years at the time of the most recent examinations. The growth pattern, neurological development, neurological signs/symptoms, and facial features were similar in the 15 female patients. Their head circumference at birth was within the normal range in about half, and their height and weight were frequently normal. This was followed by early development of severe microcephaly and postnatal growth retardation. The patients acquired head control almost normally between 3 and 6 months, followed by motor delay. More than half of the female patients had epilepsy. Their MRIs showed microcephaly, brainstem, and cerebellar hypoplasia in early infancy, and a normal or large appearing corpus callosum. The male patient showed a more severe clinical phenotype. These uniform clinical and radiological features should facilitate an early diagnosis and be useful for medical care of females with ID and MICPCH associated with CASK mutations.

Neuroradiologic features of CASK mutations

Mutations of the CASK gene are associated with X-linked mental retardation with microcephaly and disproportionate brain stem and cerebellar hypoplasia in females. The areas of the cerebrum, corpus callosum, pons, midbrain, and cerebellar vermis and hemisphere and a ratio of cerebrum/corpus callosum areas were measured in 5 female patients with CASK mutations, 67 female controls, and 5 patients with pontine hypoplasia. MR imaging in patients with CASK mutations revealed a normal size of the corpus callosum and a low ratio of the cerebrum/corpus callosum with a reduced area of the cerebrum, pons, midbrain, and cerebellar vermis and hemispheres. The 5 patients with pontine hypoplasia showed thinning of the corpus callosum and a high ratio of the cerebrum/corpus callosum, irrespective of the size of the cerebrum. The normal size of the corpus callosum, which gives an impression of callosal thickening at first glance, may be an imaging clue to detect patients with CASK mutations.