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Biomedical subjects

Alice Goldenberg

Publications and source records attributed to Alice Goldenberg.

11 recordsLinked to original sources

Systematic analysis of snRNA genes reveals frequent RNU2-2 variants in dominant and recessive developmental and epileptic encephalopathies.

Variants in spliceosomal small nuclear RNA (snRNA) genes RNU4-2 (ReNU syndrome), RNU5B-1, and RNU2-2 have recently been linked to dominant neurodevelopmental disorders (NDDs), revealing a major, previously overlooked role for noncoding snRNAs in human disease. Here, we systematically analysed 200 potentially functional snRNA genes in a French cohort comprising 26,911 individuals with rare disorders and through international collaborations. We identify de novo and biallelic variants in RNU2-2 associated with both dominant and recessive NDDs in 126 individuals from 108 unrelated families. Recessive RNU2-2 NDD is at least twice as frequent as the dominant NDD caused by n.4G>A and n.35A>G, and often arises from a de novo variant in trans with an inherited allele, reflecting the high mutability of snRNA genes. Dominant and recessive RNU2-2-NDDs share overlapping clinical features with frequent epilepsy. Blood transcriptomics and DNA methylation analyses revealed subtle, variant-specific effects on splicing and episignatures. Our findings support a gradient-of-impact model and a continuum between dominant and recessive inheritance, establishing RNU2-2 variants as a frequent cause of NDDs, nearly as prevalent as ReNU syndrome.

Journal Article↗

The characterization of new de novo CACNA1G variants affecting the intracellular gate of Cav3.1 channel broadens the spectrum of neurodevelopmental phenotypes in SCA42ND.

PURPOSE: Missense de novo variants in CACNA1G, which encodes the Cav3.1 T-type calcium channel, have been associated with a severe, early-onset form of cerebellar disorder with neurodevelopmental deficits (SCA42ND). We explored a large series of pediatric cases carrying heterozygous variants in CACNA1G to further characterize genotype-phenotype correlations in SCA42ND. METHODS: We describe 19 patients with congenital CACNA1G-variants, including 6 new heterozygotes of the recurrent SCA42ND variants, p.(Ala961Thr) and p.(Met1531Val), and 8 unreported variants, including 7 missense variants, mainly de novo. We carried out genetic and structural analyses of all variants. Patch-clamp recordings were performed to measure their channel activity. RESULTS: We provide a consolidated clinical description for the patients carrying p.(Ala961Thr) and p.(Met1531Val). The new variants associated with the more severe phenotypes are found in the Cav3.1 channel intracellular gate. Calcium currents of these Cav3.1 variants showed slow inactivation and deactivation kinetics and an increase in window current, supporting a gain of channel activity. On the contrary, the p.(Met197Arg) variant (IS4-S5 loop) resulted in a loss of channel activity. CONCLUSION: This detailed description of several de novo missense pathogenic variants in CACNA1G, including 13 previously reported cases, supports a clinical spectrum of congenital CACNA1G syndrome beyond spinocerebellar ataxia.

Humans↗

Simple detection of genomic microdeletions and microduplications using QMPSF in patients with idiopathic mental retardation.

In contrast to the numerous well-known microdeletion syndromes, only a few microduplications have been described, and this discrepancy may be due in part to methodological bias. In order to facilitate the detection of genomic microdeletions and microduplications, we developed a new assay based on QMPSF (Quantitative Multiplex PCR of Short fluorescent Fragments) able to explore simultaneously 12 candidate loci involved in mental retardation (MR) and known to be the target of genomic rearrangements. We first screened 153 patients with MR and facial dysmorphism associated with malformations, or growth anomalies, or familial history, with cytogenetically normal chromosomes, and the absence of FRAXA mutation and subtelomeric rearrangements. In this series, we found a 5q35 deletion removing the NSD1 gene in a patient with severe epilepsy, profound MR and, retrospectively, craniofacial features of Sotos syndrome. In a second series, we screened 140 patients with MR and behaviour disturbance who did not fulfil the de Vries criteria for subtelomeric rearrangements and who had a normal karyotype and no detectable FRAXA mutation. We detected a 22q11 deletion in a patient with moderate MR, obesity, and facial dysmorphism and a 4 Mb 17p11 duplication in a patient with moderate MR, behaviour disturbance, strabismus, and aspecific facial features. This new QMPSF assay can be gradually upgraded to include additional loci involved in newly recognised microduplication/microdeletion syndromes, and should facilitate wide screenings of patients with idiopathic MR and provide better estimates of the microduplication frequency in the MR population.

Child, Preschool↗

Molecular characterization of a 14q deletion in a boy with features of Holt-Oram syndrome.

Holt-Oram syndrome, the major "heart-hand" syndrome is defined by the association of radial defects or triphalangeal thumbs and septal heart defects. The transmission is autosomal dominant and the causative gene has been shown to be TBX5, located on 12q24.1, which encodes a transcription factor. Genetic heterogeneity has been suggested by several reports. We identified a 14(q23.3 approximately 24.2q31.1) deletion in a boy presenting severe bilateral asymmetrical radial aplasia, congenital heart defects, and developmental delay. This deletion, whose size could be estimated to be 9.6-13.7 Mb, was shown to be inherited via his mother's interchromosomal insertion. This is the second report of a chromosome 14 interstitial deletion associated with clinical features of Holt-Oram syndrome. These observations suggest the existence of a new "heart-hand" locus on chromosome 14q.

Abnormalities, Multiple↗

Respiratory chain deficiency presenting as congenital nephrotic syndrome.

Nephrotic syndrome (NS) in infancy includes NS of Finnish type (mutation of the nephrin gene), diffuse mesangial sclerosis (idiopathic or linked to WT1 mutation), idiopathic NS, most often steroid resistant, and NS related to infections during pregnancy (virus, syphilis, toxoplasmosis). Later in life, NS has a large variety of etiologies. It has been described in association with neuromuscular symptoms, deafness, and diabetes in a few children and adults with respiratory chain (RC) disorders. To date, however, NS has never been observed in neonates with RC disorders. Here, we report RC deficiency in one infant with certain congenital NS and two siblings with acute neonatal cardiac and renal disease with probable NS. Although clinical and histopathological presentations were initially close to congenital NS of Finnish type, clinical outcome was atypical and nephrin mutation was excluded. Mitochondrial RC complex II+V deficiency was identified in the three patients. Based on these observations, we suggest that RC disorders should be considered in patients with congenital NS.

Biopsy↗

Antenatal manifestations of Smith-Lemli-Opitz (RSH) syndrome: a retrospective survey of 30 cases.

Smith-Lemli-Opitz (SLO) syndrome or RSH syndrome is an autosomal recessive multiple malformation, and mental retardation syndrome ascribed to 7-dehydrocholesterol reductase deficiency, and usually diagnosed in the early postnatal period. Reviewing a series of 30 cases of SLO, we have investigated the variable antenatal expression of the disorder. Intrauterine growth retardation (IUGR) was the most frequent detectable trait (20/30). IUGR was either isolated (9/20) or associated with at least one other anomaly (11/20), including nuchal edema, renal, cardiac, cerebral malformations, genital anomalies, or polydactyly. In this last group, 3/11 presented with multiple malformations (> or =3 anomalies). In 5/30 cases, isolated nuchal edema (3/30), and isolated cardiac (1/30) or renal malformations (1/30) were the only detectable anomalies. Ultrasound findings were considered normal in 5/30 cases and were abnormal in 25/30 cases (83%), but early detection of multiple malformations was rare (3/30, 10%). We suggest giving consideration to a more systematic sterol analysis when dealing with IUGR, especially when associated anomalies are detected.

Female↗

Werner mesomelic dysplasia with Hirschsprung disease.

Mesomelic dysplasia type Werner is defined by absence of tibiae and preaxial polysyndactyly of hands and feet. Occasional findings are triphalangeal thumbs, absence of patella(e), and dislocated fibula(e). The molecular basis is unknown and autosomal dominant inheritance with variable expressivity is currently postulated. Hirschsprung disease was reported previously in one case. We report here on a new case of mesomelic dysplasia Werner type associated with Hirschsprung disease and bilateral cryptorchidism. We discuss the overlap with the triphalangeal thumb polysyndactyly syndrome located in chromosome 7q36.

Abnormalities, Multiple↗

Genotyping microsatellite DNA markers at putative disease loci in inbred/multiplex families with respiratory chain complex I deficiency allows rapid identification of a novel nonsense mutation (IVS1nt -1) in the NDUFS4 gene in Leigh syndrome.

Complex I deficiency, the most common cause of mitochondrial disorders, accounts for a variety of clinical symptoms and its genetic heterogeneity makes identification of the disease genes particularly tedious. Indeed, most of the 43 complex I subunits are encoded by nuclear genes, only seven of them being mitochondrially encoded. In order to offer urgent prenatal diagnosis, we have studied an inbred/multiplex family with complex I deficiency by using microsatellite DNA markers flanking the putative disease loci. Microsatellite DNA markers have allowed us to exclude the NDUFS7, NDUFS8, NDUFV1 and NDUFS1 genes and to find homozygosity at the NDUFS4 locus. Direct sequencing has led to identification of a homozygous splice acceptor site mutation in intron 1 of the NDUFS4 gene (IVS1nt -1, G-->A); this was not found in chorion villi of the ongoing pregnancy. We suggest that genotyping microsatellite DNA markers at putative disease loci in inbred/multiplex families helps to identify the disease-causing mutation. More generally, we suggest giving consideration to a more systematic microsatellite analysis of putative disease loci for identification of disease genes in inbred/multiplex families affected with genetically heterogeneous conditions.

Codon, Nonsense↗

Antenatal manifestations of mitochondrial respiratory chain deficiency.

OBJECTIVE: To review the antenatal manifestations of disorders of oxidative phosphorylation. STUDY DESIGN: A total of 300 cases of proven respiratory chain enzyme deficiency were retrospectively reviewed for fetal development, based on course and duration of pregnancy, antenatal ultrasonography and birth weight, length, and head circumference. Particular attention was given to fetal movements, oligo/hydramnios, fetal cardiac rhythm, fetal heart ultrasound, and ultrasonography/echo Doppler signs of brain, facial, trunk, limb, and organ anomalies. RESULTS: Retrospective analyses detected low birth weight (<3rd percentile for gestational age) in 22.7% of cases (68/300, P<.000001). Intrauterine growth retardation was either isolated (48/300, 16%) or associated with otherwise unexplained anomalies (20/300, 6.7%, P<.0001). Antenatal anomalies were usually multiple and involved several organs sharing no common function or embryologic origin. They included polyhydramnios (6/20), oligoamnios (2/20), arthrogryposis (1/20), decreased fetal movements (1/20), ventricular septal defects (2/20), hypertrophic cardiomyopathy (4/20), cardiac rhythm anomalies (4/20), hydronephrosis (3/20), vertebral abnormalities, anal atresia, cardiac abnormalities, tracheoesophageal fistula/atresia, renal agenesis and dysplasia, and limb defects (VACTERL) association (2/20), and a complex gastrointestinal malformation (1/20). CONCLUSIONS: Although a number of metabolic diseases undergo a symptom-free period, respiratory chain deficiency may have an early antenatal expression, presumably related to the time course of the disease gene expression in the embryofetal period. The mechanism triggering malformations is unknown and may include decreased ATP formation and/or an alteration of apoptotic events controlled by the mitochondria.

Birth Weight↗

Facial appearance in persistent hyperinsulinemic hypoglycemia.

Persistent hyperinsulinism is the most common cause of recurrent hypoglycemia in infancy because of inappropriate oversecretion of insulin by the pancreas. Pancreatic lesions can be either focal or diffuse, and they have distinct molecular bases. We have studied the facial features in 17 unrelated patients presenting with neonatal (n = 8) or infancy-onset (n = 9) hyperinsulinism. Hyperinsulinism was related to focal adenomatous hyperplasia (n = 7), diffuse hyperinsulinism (n = 5), non-operated hyperinsulinism (n = 2), and hyperinsulinism with hyperammonemia (n = 3). SUR1 or Kir6.2 mutations were found in six of seven focal adenomatous hyperplasia and three of five diffuse hyperinsulinism. A loss of the maternal allele from chromosome 11p15 in the lesion was found in all focal adenomatous hyperplasia. GLUD1 mutations were found in all patients with hyperammonemia. Large birth weight (mean > 3,800 g) was consistently observed (11/17) but protruding tongue, exomphalos, or visceromegaly were never noted and Wiedemann-Beckwith syndrome could always be ruled out. All patients presented with high forehead, small nasal tip, and short columella giving the impression that the nose is large and bulbous, smooth philtrum, and thin upper lip. A square appearance to the face was more obvious in younger patients. These specific facial features, observed in patients with hyperinsulinism of various molecular mechanisms, could be the consequence of fetal intoxication by insulin. However, to date, facial anomalies have not been noted in infants of diabetic mothers and inversely, malformations that are commonly reported in infants of diabetic mothers were not present in our hyperinsulinemic patients.

ATP-Binding Cassette Transporters↗