Clinical description of a patient carrying the smallest reported deletion involving 10p14 region.

Haploinsufficiency of a region located distal to 10p14 designated HDR1, is responsible for hypoparathyroidism, sensorineural deafness, and renal anomalies (HDR syndrome). Haploinsufficiency of a more proximal region, located on 10p13-10p14, designated as DGCR2 is associated with congenital heart defects and thymus hypoplasia/aplasia or T cell defect. We describe a patient showing facial dysmorphisms, delayed psychomotor development and bilateral sensorineural hearing loss and carrying a 10p14 deletion, the smallest deletion found in the literature so far. Our patient, carrying a partial deletion of the DGCR2 region and of the HDR1 region, including the GATA3 gene, showed, unexpectedly, only few of the clinical features of DiGeorge 2 syndrome (psychomotor retardation, palpebral ptosis, epicanthic folds, anteverted nares, cryptorchidism, hand/foot abnormalities) and did not show other typical signs, such as cardiac defect, cleft palate, and abnormal T cell levels. Of the three characteristic features of the HDR syndrome, our patient had only sensorineural deafness. On the basis of the revision of the other cases reported in the literature with a deletion including the 10p14 region, we suggest that GATA3 haploinsufficiency, although not recorded for each patient, is responsible for deafness. The present case shows that even this small 10p deletion is responsible for a specific phenotype. We also underline the importance of CGH-array, in order to obtain a more precise physical mapping of the 10p deletions and an accurate genotype-phenotype correlation.

Mental retardation, congenital heart malformation, and myelodysplasia in a patient with a complex chromosomal rearrangement involving the critical region 21q22.

The region 21q22 is considered crucial for the pathogenesis of both Down syndrome (DS) and the partial monosomy 21q syndrome. Haploinsufficiency of the RUNX-1 gene, mapping at 21q22 is responsible for a platelet disorder and causes predisposition to myelodysplastic syndrome (MDS). We describe a 3-year-old girl with mental retardation, congenital heart malformation, and subtle dysmorphic facial features. The patient developed thrombocytopenia when she was 2 years old. Bone marrow smear led to the diagnosis of myelodysplasia. Prenatal karyotyping had shown chromosome 21 pericentric inversion. Postnatally the array-CGH revealed duplication at bands 21q11.2-21q21.1 and a simultaneous deletion involving the region 21q22.13-21q22.3. RUNX-1 mRNA levels analyzed in patient's skin fibroblasts were reduced. In this child the monosomy of the region 21q22 likely had the main role in determining the phenotype. Although the RUNX-1 gene is localized outside the deleted region, we speculate that RUNX-1 reduced expression, is probably due to the deletion of regulatory factors and caused the hematologic disorder in the patient. The present report underlines also the importance of array-CGH in characterizing patients with a complex phenotype.

Intrafamilial variability in SPTAN1-related disorder: From benign convulsions with mild gastroenteritis to developmental encephalopathy.

Mutations in SPTAN1 gene are responsible for a wide spectrum of neurodevelopmental disorders including early-onset epileptic encephalopathy with progressive brain atrophy, severe intellectual disability with cerebellar malformations, and relatively milder phenotypes with or without epilepsy. Herein, we report three affected individuals including two siblings of 13 and 8 years and their 39-year-old mother, carrying a novel pathogenic variant in SPTAN1 gene. The phenotype of the index cases and their mother was remarkable for the variable expressivity, including benign convulsions with mild gastroenteritis, intellectual disability and developmental encephalopathy with epilepsy. Our clinical observation suggests for the first time that variants in SPTAN1 gene might be involved in the aetiology of benign convulsions correlated with mild gastroenteritis.

Microdeletion of pseudogene chr14.232.a affects LRFN5 expression in cells of a patient with autism spectrum disorder.

We identified a 14q21.2 microdeletion in a 16-year-old boy with autism spectrum disorder (ASD), IQ in the lower part of normal range but high-functioning memory skills. The deletion affects a gene desert, and the non-deleted gene closest to the microdeletion boundaries is LRFN5, which encodes a protein involved in synaptic plasticity and implicated in neuro-psychiatric disorders. LRFN5 expression was significantly decreased in the proband's skin fibroblasts. The deleted region includes the pseudogene chr14.232.a, which is transcribed into a long non-coding RNA (lncLRFN5-10), whose levels were also significantly reduced in the proband's fibroblasts compared to controls. Transfection of the patient's fibroblasts with a plasmid expressing chr14.232.a significantly increased LRFN5 expression, while siRNA targeting chr14.232.a-derived lncLRFN5-10 reduced LRFN5 levels. In summary, we report on an individual with ASD carrying a microdeletion encompassing the pseudogene chr14.232.a encoding for lncLRFN5-10, which was found to affect the expression levels of the nearby, non-deleted LRFN5. This case illustrates the potential role of long non-coding RNAs in regulating expression of neighbouring genes with a functional role in ASD pathogenesis.

A novel SHANK3 interstitial microdeletion in a family with intellectual disability and brain MRI abnormalities resembling Unidentified Bright Objects.

BACKGROUND: SHANK3 mutations are responsible for Phelan-McDermid syndrome but they are also associated with autism and/or intellectual disability. CASE REPORT: We report a family with four affected individuals including the 37 year-old mother, her 12 year-old male monozygotic twins and 8 year-old daughter harboring a novel SHANK3 interstitial microdeletion. All four members presented with intellectual disability of variable severity. The twins showed brain abnormalities similar to Unidentified Bright Objects (UBOs), typically detected in patients with Neurofibromatosis type 1 (NF1), but they did not display causative mutations in NF1 gene. CONCLUSION: To date, this is the first report of an affected individual with SHANK3 interstitial deletion able to reproduce. Moreover, we found a previously unreported possible association between SHANK3 deletion and UBOs-like lesions in the brain.

Taylor-type focal cortical dysplasia: is the epilepsy always resistant to medical treatment?

Patients with Taylor-type focal cortical dysplasia (TTFCD) generally present with medically intractable epilepsy and impaired neurological and/or intellectual functioning. Surgery usually proves to be the only treatment approach leading to control of seizures. We describe a 17-year-old girl with TTFCD who exhibited a very long period of seizure remission. Combined clinical and neuroimaging findings were compatible with a diagnosis of a balloon cell-subtype TTFCD. As for the clinical course, partial motor seizures began at one year of age and ceased at five: our patient has had no seizure recurrence over a 12-year-follow-up. Moreover, throughout the 15-year follow-up, neurological examinations and cognitive abilities always remained within normal limits. Neuropsychological assessment clearly showed no impairments in executive functions: planning abilities, working memory, attention and impulse control, or constructive aspects of motor coordination. The predominant deficits pertained to verbal abilities in the context of borderline intellectual performances. To our knowledge, this case report documents the longest duration of seizure remission in a patient with TTFCD, thus emphasizing the possible benign course of such dysplastic lesions which usually have a poor prognosis, leading to early surgical treatment.

CNS involvement in OFD1 syndrome: a clinical, molecular, and neuroimaging study.

BACKGROUND: Oral-facial-digital type 1 syndrome (OFD1; OMIM 311200) belongs to the expanding group of disorders ascribed to ciliary dysfunction. With the aim of contributing to the understanding of the role of primary cilia in the central nervous system (CNS), we performed a thorough characterization of CNS involvement observed in this disorder. METHODS: A cohort of 117 molecularly diagnosed OFD type I patients was screened for the presence of neurological symptoms and/or cognitive/behavioral abnormalities on the basis of the available information supplied by the collaborating clinicians. Seventy-one cases showing CNS involvement were further investigated through neuroimaging studies and neuropsychological testing. RESULTS: Seventeen patients were molecularly diagnosed in the course of this study and five of these represent new mutations never reported before. Among patients displaying neurological symptoms and/or cognitive/behavioral abnormalities, we identified brain structural anomalies in 88.7%, cognitive impairment in 68%, and associated neurological disorders and signs in 53% of cases. The most frequently observed brain structural anomalies included agenesis of the corpus callosum and neuronal migration/organisation disorders as well as intracerebral cysts, porencephaly and cerebellar malformations. CONCLUSIONS: Our results support recent published findings indicating that CNS involvement in this condition is found in more than 60% of cases. Our findings correlate well with the kind of brain developmental anomalies described in other ciliopathies. Interestingly, we also described specific neuropsychological aspects such as reduced ability in processing verbal information, slow thought process, difficulties in attention and concentration, and notably, long-term memory deficits which may indicate a specific role of OFD1 and/or primary cilia in higher brain functions.

Selective cognitive impairment and tall stature due to chromosome 19 supernumerary ring.

Small supernumerary marker chromosomes (sSMC) occur with a frequency of approximately 0.4 per 1000 newborns and are more frequent in the population with mental retardation and/or with dysmorphic signs. Small supernumerary chromosome rings (sSCR) usually occur as apart of a mosaic karyotype (Liehr et al., 2004). Chromosome 19 supernumerary rings are very rare. Almost all cases of sSMC19 have been reported on Thomas Liehr's website (http://www.med.uni-jena.de/fish/sSMC/19.htm#Start19). Of these cases, 14 were with phenotypic abnormalities and a clear characterization of the sSMC; two cases were suitable for comparison with our case with regard to their genetic content, but not with regard to the structure ofthe sSMC (Manvelyan et al., 2008). The phenotype, associated with partial trisomy 19q, includes facial dysmorphism, growth and mental retardation, macrocephaly, heart malformation and anomalies of the genitourinary and gastrointestinal tracts. The phenotype associated with partial trisomy 19p is characterized by dysmorphic features, severe mental retardation, abnormalities of brain morphology and anomalies of the fingers (Tercanli et al., 2000; Qorri et al., 2002; Novelli et al., 2005; Vranekovic et al., 2008). Herein, we report the phenotype and molecular cytogenetic analysis in a patient with the smallest de-novo constitutional ring extended from the p12 to q12 region of chromosome 19.

A further contribution to the delineation of the 17q21.31 microdeletion syndrome: central nervous involvement in two Italian patients.

The 17q21.31 microdeletion syndrome is a genetic disorder characterized by intellectual disability, facial dysmorphisms and a typical behavioral phenotype. Patients are usually described as friendly and cooperative but they can also show behavioral problems such as hyperactivity, bad humor, temper tantrums and poor interaction. Central nervous system involvement includes callosal dysgenesis/absence, enlargement of lateral ventricles and abnormalities of cyngulate gyrus. We report on two Italian patients with the 17q21.31 microdeletion syndrome better emphasizing neuroimaging and neuropsychological characteristics. In particular, we carried out an assessment of intellectual efficiency and behavior that turned out to be within the mild-moderate range of mental retardation, as already reported in the literature. To the best of our knowledge this is the first report of a patient with the 17q21.31 microdeletion and a Chiari malformation type 1 coexisting with a mild anomaly of medulla oblongata. This malformation should be considered in patients with the 17q21.31 microdeletion syndrome, presenting suggestive symptoms (headache, neck pain, cerebellar signs or muscle weakness).

An emerging phenotype of proximal 11q deletions.

Few reports of small interstitial chromosome 11q deletions are reported in the literature and no clear genotype-phenotype correlation has been demonstrated. We describe a five years old boy who was referred to our attention because of the presence of ptosis of the left eyelid, iris coloboma and developmental delay. Clinical examination also revealed the presence of dysmorphic features including: low frontal hairline, flat profile, round face, full cheeks, periorbital fullness, hypertelorism, broad nasal bridge, down-turned corners of the mouth. Cytogenetic analysis, performed by array-CGH (resolution 1 Mb), revealed a deletion of chromosome 11q13.5q14.2. The present case represents a further patient described in the literature with a small interstitial deletion of chromosome 11q. Our patient shares the dysmorphic features and the presence of developmental delay with the previously reported patients with overlapping proximal 11q deletion. Considering these clinical and cytogenetic similarities, we suggest the existence of an emerging syndrome associated to proximal 11q deletions.

Cerebellar vermis aplasia: patient report and exclusion of the candidate genes EN2 and ZIC1.

Cerebellar vermis aplasia (ACV, OMIM 117360) is a rare malformation of the cerebellum, with only few familial patients reported so far. Main clinical features of this rare disorder include floppiness and delayed milestones in early infancy, preceding mild cerebellar ataxia, non-progressive clinical course, normal or slightly delayed intelligence, and occasional nystagmus. Neuroimaging reveals selective involvement of the cerebellum, which is prominent in the vermis. Because of the large preponderance of female patients, X-linked dominant transmission was suggested by [Fenichel and Phillips (1989); Arch Neurol 46:582-583], and subsequent reports only concern female patients. Only one family with male-to-male transmission presenting with a generalized atrophy of the cerebellum rather than a more localized vermis aplasia has been reported so far. We report on a family in which father and son are affected by a mild form of ACV, thus confirming an autosomal mode of inheritance of the disease. Our patients showed a progressive improvement of their motor abilities, neurological examination of the father being actually normal except for a mild mental retardation. We also evaluated the potential role of two candidate genes, EN2 and ZIC1, responsible for abnormal cerebellar development in murine knock-out models. However, molecular analysis failed to reveal any causative mutation in the coding sequence of the two genes in our patients. The understanding of the genetic basis of autosomal dominant ACV would allow a better classification of isolate cerebellar malformations and might permit to understand cell differentiation and migration in the developing central nervous system.