Inspired by a patient
Jacquin C, Landais E, Poirsier C, Afenjar A, Akhavi A, Bednarek N, Bénech C, Bonnard A, Bosquet D, Burglen L, Callier P, Chantot-Bastaraud S, Coubes C, Coutton C, Delobel B, Descharmes M, Dupont JM, Gatinois V, Gruchy N, Guterman S, Heddar A, Herissant L, Heron D, Isidor B, Jaeger P, Jouret G, Keren B, Kuentz P, Le Caignec C, Levy J, Lopez N, Manssens Z, Martin-Coignard D, Marey I, Mignot C, Missirian C, Pebrel-Richard C, Pinson L, Puechberty J, Redon S, Sanlaville D, Spodenkiewicz M, Tabet AC, Verloes A, Vieville G, Yardin C, Vialard F, Doco-Fenzy M. 1p36 deletion syndrome: Review and mapping with further characterization of the phenotype, a new cohort of 86 patients. Am J Med Genet A. 2023 Feb;191(2):445-458. doi: 10.1002/ajmg.a.63041. Epub 2022 Nov 11. PMID: 36369750; PMCID: PMC10100125.
Abstract
Chromosome 1p36 deletion syndrome (1p36DS) is one of the most common terminal deletion syndromes (incidence between 1/5000 and 1/10,000 live births in the American population), due to a heterozygous deletion of part of the short arm of chromosome 1. The 1p36DS is characterized by typical craniofacial features, developmental delay/intellectual disability, hypotonia, epilepsy, cardiomyopathy/congenital heart defect, brain abnormalities, hearing loss, eyes/vision problem, and short stature. The aim of our study was to (1) evaluate the incidence of the 1p36DS in the French population compared to 22q11.2 deletion syndrome and trisomy 21; (2) review the postnatal phenotype related to microarray data, compared to previously publish prenatal data. Thanks to a collaboration with the ACLF (Association des Cytogénéticiens de Langue Française), we have collected data of 86 patients constituting, to the best of our knowledge, the second-largest cohort of 1p36DS patients in the literature. We estimated an average of at least 10 cases per year in France. 1p36DS seems to be much less frequent than 22q11.2 deletion syndrome and trisomy 21. Patients presented mainly dysmorphism, microcephaly, developmental delay/intellectual disability, hypotonia, epilepsy, brain malformations, behavioral disorders, cardiomyopathy, or cardiovascular malformations and, pre and/or postnatal growth retardation. Cardiac abnormalities, brain malformations, and epilepsy were more frequent in distal deletions, whereas microcephaly was more common in proximal deletions. Mapping and genotype-phenotype correlation allowed us to identify four critical regions responsible for intellectual disability. This study highlights some phenotypic variability, according to the deletion position, and helps to refine the phenotype of 1p36DS, allowing improved management and follow-up of patients.
Greco M, Ferrara P, Farello G, Striano P, Verrotti A. Electroclinical features of epilepsy associated with 1p36 deletion syndrome: A review. Epilepsy Res. 2018 Jan;139:92-101. doi: 10.1016/j.eplepsyres.2017.11.016. Epub 2017 Dec 2. PMID: 29212048.
Abstract
1p36 terminal deletion is a recently recognized syndrome with multiple congenital anomalies and intellectual disability. It occurs approximately in 1 out of 5000 to 10,000 live births and is the most common subtelomeric microdeletion observed in human. Medical problems commonly caused by terminal deletions of 1p36 include developmental delay, intellectual disability, seizures, vision problems, hearing loss, short stature, brain anomalies, congenital heart defects, cardiomyopathy, renal anomalies and distinctive facial features. Although the syndrome is considered clinically recognizable, there is significant phenotypic variation among affected individuals. Genotype-phenotype correlation in this syndrome is complicated, because of the similar clinical evidence seen in patients with different deletion sizes. We review 34 scientific articles from 1996 to 2016 that described 315 patients with 1p36 delection syndrome. The aim of this review is to find a correlation between size of the 1p36-deleted segments and the neurological clinical phenotypes with the analysis of electro-clinical patterns associated with chromosomal aberrations, that is a major tool in the identification of epilepsy susceptibility genes. Our finding suggest that developmental delay and early epilepsy are frequent findings in 1p36 deletion syndrome that can contribute to a poor clinical outcome for this reason this syndrome should be searched for in patients presenting with infantile spasms associated with a hypsarrhythmic EEG, particulary if they are combined with dismorphic features, severe hypotonia and developmental delay.
Carter LB, Battaglia A, Cherry A, Manning MA, Ruzhnikov MR, Bird LM, Dowsett L, Graham JM Jr, Alkuraya FS, Hashem M, Dinulos MB, Vallee S, Adam MP, Glass I, Beck AE, Stevens CA, Zackai E, McDougall C, Keena B, Peron A, Vignoli A, Seaver LH, Slavin TP, Hudgins L. Perinatal distress in 1p36 deletion syndrome can mimic hypoxic ischemic encephalopathy. Am J Med Genet A. 2019 Aug;179(8):1543-1546. doi: 10.1002/ajmg.a.61266. Epub 2019 Jun 17. PMID: 31207089; PMCID: PMC7254578.
Abstract
1p36 deletion syndrome is a well-described condition with a recognizable phenotype, including cognitive impairment, seizures, and structural brain anomalies such as periventricular leukomalacia (PVL). In a large series of these individuals by Battaglia et al., "birth history was notable in 50% of the cases for varying degrees of perinatal distress." Given the potential for perinatal distress, seizures and PVL, we questioned if this disorder has clinical overlap with hypoxic ischemic encephalopathy (HIE). We reviewed the medical records of 69 individuals with 1p36 deletion to clarify the perinatal phenotype of this disorder and determine if there is evidence of perinatal distress and/or hypoxic injury. Our data provides evidence that these babies have signs of perinatal distress. The majority (59% term; 75% preterm) needed resuscitation and approximately 18% had cardiac arrest. Most had abnormal brain imaging (84% term; 73% preterm) with abnormal white matter findings in over half of patients. PVL or suggestion of "hypoxic insult" was present in 18% of term and 45% of preterm patients. In conclusion, individuals with 1p36 deletion have evidence of perinatal distress, white matter changes, and seizures, which can mimic HIE but are likely related to their underlying chromosome disorder.
Rocha CF, Vasques RB, Santos SR, Paiva CL. Mini-Review: Monosomy 1p36 syndrome: reviewing the correlation between deletion sizes and phenotypes. Genet Mol Res. 2016 Feb 22;15(1). doi: 10.4238/gmr.15017942. PMID: 26910004.
Abstract
The major clinical features of monosomy 1p36 deletion are developmental delay and hypotonia associated with short stature and craniofacial dysmorphisms. The objective of this study was to review the cases of 1p36 deletion that was reported between 1999 and 2014, in order to identify a possible correlation between the size of the 1p36-deleted segment and the clinical phenotype of the disease. Scientific articles published in the (National Center for Biotechnology Information; NCBI http://www.ncbi.nlm.nih.gov/pubmed) and Scientific Electronic Library Online (www.scielo.com.br) databases were searched using key word combinations, such as "1p36 deletion", "monosomy 1p36 deletion", and "1p36 deletion syndrome". Articles in English or Spanish reporting the correlation between deletion sizes and the respective clinical phenotypes were retrieved, while letters, reviews, guidelines, and studies with mouse models were excluded. Among the 746 retrieved articles, only 17 (12 case reports and 5 series of cases), comprising 29 patients (9 males and 20 females, aged 0 months (neonate) to 22 years) bearing the 1p36 deletions and whose clinical phenotypes were described, met the inclusion criteria. The genotype-phenotype correlation in monosomy 1p36 is a challenge because of the variability in the size of the deleted segment, as well as in the clinical manifestations of similar size deletions. Therefore, the severity of the clinical features was not always associated with the deletion size, possibly because of the other influences, such as stochastic factors, epigenetic events, or reduced penetration of the deleted genes.
Shimada S, Shimojima K, Okamoto N, Sangu N, Hirasawa K, Matsuo M, Ikeuchi M, Shimakawa S, Shimizu K, Mizuno S, Kubota M, Adachi M, Saito Y, Tomiwa K, Haginoya K, Numabe H, Kako Y, Hayashi A, Sakamoto H, Hiraki Y, Minami K, Takemoto K, Watanabe K, Miura K, Chiyonobu T, Kumada T, Imai K, Maegaki Y, Nagata S, Kosaki K, Izumi T, Nagai T, Yamamoto T. Microarray analysis of 50 patients reveals the critical chromosomal regions responsible for 1p36 deletion syndrome-related complications. Brain Dev. 2015 May;37(5):515-26. doi: 10.1016/j.braindev.2014.08.002. Epub 2014 Aug 27. PMID: 25172301.
Abstract
Objective: Monosomy 1p36 syndrome is the most commonly observed subtelomeric deletion syndrome. Patients with this syndrome typically have common clinical features, such as intellectual disability, epilepsy, and characteristic craniofacial features.
Method: In cooperation with academic societies, we analyzed the genomic copy number aberrations using chromosomal microarray testing. Finally, the genotype-phenotype correlation among them was examined.
Results: We obtained clinical information of 86 patients who had been diagnosed with chromosomal deletions in the 1p36 region. Among them, blood samples were obtained from 50 patients (15 males and 35 females). The precise deletion regions were successfully genotyped. There were variable deletion patterns: pure terminal deletions in 38 patients (76%), including three cases of mosaicism; unbalanced translocations in seven (14%); and interstitial deletions in five (10%). Craniofacial/skeletal features, neurodevelopmental impairments, and cardiac anomalies were commonly observed in patients, with correlation to deletion sizes.
Conclusion: The genotype-phenotype correlation analysis narrowed the region responsible for distinctive craniofacial features and intellectual disability into 1.8-2.1 and 1.8-2.2 Mb region, respectively. Patients with deletions larger than 6.2 Mb showed no ambulation, indicating that severe neurodevelopmental prognosis may be modified by haploinsufficiencies of KCNAB2 and CHD5, located at 6.2 Mb away from the telomere. Although the genotype-phenotype correlation for the cardiac abnormalities is unclear, PRDM16, PRKCZ, and RERE may be related to this complication. Our study also revealed that female patients who acquired ambulatory ability were likely to be at risk for obesity.
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