Although the best-known spinocerebellar ataxias (SCAs) are triplet repeat diseases, many SCAs are not caused by repeat expansions. The rarity of individual non-expansion SCAs, however, has made it... Show moreAlthough the best-known spinocerebellar ataxias (SCAs) are triplet repeat diseases, many SCAs are not caused by repeat expansions. The rarity of individual non-expansion SCAs, however, has made it difficult to discern genotype-phenotype correlations. We therefore screened individuals who had been found to bear variants in a non-expansion SCA-associated gene through genetic testing, and after we eliminated genetic groups that had fewer than 30 subjects, there were 756 subjects bearing single-nucleotide variants or deletions in one of seven genes: CACNA1A (239 subjects), PRKCG (175), AFG3L2 (101), ITPR1 (91), STUB1 (77), SPTBN2 (39), or KCNC3 (34). We compared age at onset, disease features, and progression by gene and variant. There were no features that reliably distinguished one of these SCAs from another, and several genes—CACNA1A, ITPR1, SPTBN2, and KCNC3—were associated with both adult-onset and infantile-onset forms of disease, which also differed in presentation. Nevertheless, progression was overall very slow, and STUB1-associated disease was the fastest. Several variants in CACNA1A showed particularly wide ranges in age at onset: one variant produced anything from infantile developmental delay to ataxia onset at 64 years of age within the same family. For CACNA1A, ITPR1, and SPTBN2, the type of variant and charge change on the protein greatly affected the phenotype, defying pathogenicity prediction algorithms. Even with next-generation sequencing, accurate diagnosis requires dialogue between the clinician and the geneticist. Show less
Cappuccio, G.; Brillante, S.; Tammaro, R.; Pinelli, M.; Bernardi, M.L. de; Gensini, M.G.; ... ; Brunetti-Pierri, N. 2022
Biallelic loss-of-function (LoF) variants in CENPF gene are responsible for Stromme syndrome, a condition presenting with intestinal atresia, anterior ocular chamber anomalies, and microcephaly.... Show moreBiallelic loss-of-function (LoF) variants in CENPF gene are responsible for Stromme syndrome, a condition presenting with intestinal atresia, anterior ocular chamber anomalies, and microcephaly. Through an international collaboration, four individuals (three males and one female) carrying CENPF biallelic variants, including two missense variants in homozygous state and four LoF variants, were identified by exome sequencing. All individuals had variable degree of developmental delay/intellectual disability and microcephaly (ranging from -2.9 SDS to -5.6 SDS) and a recognizable pattern of dysmorphic facial features including inverted-V shaped interrupted eyebrows, epicanthal fold, depressed nasal bridge, and pointed chin. Although one of the cases had duodenal atresia, all four individuals did not have the combination of internal organ malformations of Stromme syndrome (intestinal atresia and anterior eye segment abnormalities). Immunofluorescence analysis on skin fibroblasts on one of the four cases with the antibody for ARL13B that decorates primary cilia revealed shorter primary cilia that are consistent with a ciliary defect. This case-series of individuals with biallelic CENPF variants suggests the spectrum of clinical manifestations of the disorder that may be related to CENPF variants is broad and can include phenotypes lacking the cardinal features of Stromme syndrome. Show less
Brunetti-Pierri, N.; Paciorkowski, A.R.; Ciccone, R.; Mina, E. della; Bonaglia, M.C.; Borgatti, R.; ... ; Stankiewicz, P. 2011
Genome-wide high-resolution array analysis is rapidly becoming a reliable method of diagnostic investigation in individuals with mental retardation and congenital anomalies, leading to the... Show moreGenome-wide high-resolution array analysis is rapidly becoming a reliable method of diagnostic investigation in individuals with mental retardation and congenital anomalies, leading to the identification of several novel microdeletion and microduplication syndromes. We have identified seven individuals with duplication on chromosome 14q11.2q13.1, who exhibited idiopathic developmental delay and cognitive impairment, severe speech delay, and developmental epilepsy. Among these cases, the minimal common duplicated region on chromosome 14q11.2q13.1 includes only three genes, FOXG1, C14orf23, and PRKD1. We propose that increased dosage of Forkhead Box G1 (FOXG1) is the best candidate to explain the abnormal neurodevelopmental phenotypes observed in our patients. Deletions and inactivating mutations of FOXG1 have been associated with a Rett-like syndrome characterized by hypotonia, irritability, developmental delay, hand stereotypies, and deceleration of head growth. FOXG1, encoding a brain-specific transcription factor, has an important role in the developing brain. In fact, in vivo studies in chicken brain demonstrated that overexpression of FOXG1 results in thickening of the neuroepithelium and outgrowth of the telencephalon and mesencephalum, secondary to a reduction in neuroepithelial cell apoptosis. European Journal of Human Genetics (2011) 19, 102-107; doi:10.1038/ejhg.2010.142; published online 25 August 2010 Show less
