Unique maternal deletion of 15q in a patient with some symptoms of Prader-Willi syndrome

BACKGROUND: Human chromosome 15q11-q13 is a critical region for Prader-Willi syndrome (PWS) and Angelman syndrome (AS) and most of the genes are under the condition of imprinting mechanism. PWS results from the loss of expression of paternally expressed genes and AS of maternally expressed genes. In this study molecular studies about a patient with congenital anomalies and mental retardation are analyzed. METHODS: Highly polymorphic microsatellite markers were analyzed by PCR. These markers exist within 15q11-q13 and distal to 15q13. RESULTS: Only the maternal D15S986 locus within 15q11-q13 was deleted and other markers were biallelic. CONCLUSIONS: The result of maternal small region deletion in this patient is different from the typical PWS with paternal chromosome deletion and it suggests that nearby the deleted region there exists a gene (genes) which is not imprinted but needs biallelic expression.     

Hepatoblastoma in an infant with paternal uniparental disomy 14

A 29‐year‐old primigravida developed polyhydramnios at 24 weeks of gestation, requiring six serial amnioreductions. In addition, prenatal ultrasound examinations revealed a fetus with small stomach pouch, small thorax, slightly shortened limbs, and skin edema; paternal uniparental disomy 14(upd(14)pat) phenotype was suspected. At 37 weeks, the patient delivered a 2558 g female infant with characteristic facial features, webbed neck, thoracic deformity, abdominal wall defect, skin edema, overlapping fingers, placentomegaly, and small thorax with ‘coat‐hanger’ appearance of the ribs on chest X‐ray. A phenotype consistent with upd(14)pat was confirmed by DNA analysis. Although the infant's condition was initially stable, hepatoblastoma was subsequently detected and right hepatectomy was performed on day 224. On day 382, the infant was discharged with in‐home respiratory management.     

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??Objective??To study clinical features and diagnostic means of children with Prader-Willi syndrome??PWS?? from neonatal period to adolescence. Methods??Conduct retrospective analysis of clinical characteristics and genetic testing results of children with PWS in Children’s Hospital of Chongqing Medical University from January 2010 to January 2016. Results??Totally 46 children with PWS were chosen??28 male??18 female??the ratio of male to female being 3??2??the age of children receiving medication for the first time ranges from birth to 9 years old??the age of diagnosed children ranges from 14 days to 14 years??and the longest course of PWS had lasted for 9 years. The main clinical manifestations included hypotonia??28 cases??60%????feeding difficulties??20 cases??44%????low crying??18 cases??40%????disturbance of intelligence??42 cases??92%????obesity??25 cases??55%?? and microsomia??26 cases??57%????etc. Different ages showed different performances??newborns??0-28 days?? mainly had hypotonia??weak crying??poor suck??infants??29 days-1 year?? mainly showed backward motor development??hypotonia??weak crying??poor suck??special facial features and skin hypopigmentation etc.??babies??1-3 years?? mainly showed backward motor and intelligent development??hypotonia and skin hypopigmentation etc. Children????3 years?? mainly showed backward intelligent development??bulimia??obesity??microsomia and agenosomia??incomplete sextual development??. Among the samples??44 cases were 15q11-13 region deletion of paternal origin of the genetic material??96%????whilst 2 cases were uniparental disomy of maternal origin of the genetic material??4%??. Conclusion??As different children with PWS show different clinical manifestations??earlier genetic testing is beneficial to the early diagnosis.     

Fibroadenoma in Beckwith–Wiedemann syndrome with paternal uniparental disomy of chromosome 11p15.5

Herein is described a case of breast fibroadenomas in a 16‐year‐old girl with Beckwith–Wiedemann syndrome (BWS) and uniparental disomy (UPD) of chromosome 11p15.5. She was clinically diagnosed with BWS and direct closure was performed for an omphalocele at birth. Subtotal and 90% pancreatectomy were performed for nesidioblastosis at the ages 2 months and 8 years, respectively. Bilateral multiple breast fibroadenomas were noted at the age of 16 and 17 years. In this case, paternal UPD of chromosome 11p15.5 was identified on microsatellite marker analysis. The relevant imprinted chromosomal region in BWS is 11p15.5, and UPD of chromosome 11p15 is a risk factor for BWS‐associated tumorigenicity. Chromosome 11p15.5 consists of imprinting domains of IGF2, the expression of which is associated with the tumorigenesis of various breast cancers. This case suggests that fibroadenomas occurred in association with BWS.     

Prader-Willi syndrome: intellectual abilities and behavioural features by genetic subtype

BACKGROUND: Studies of chromosome 15 abnormality have implicated over-expression of paternally imprinted genes in the 15q11-13 region in the aetiology of autism. To test this hypothesis we compared individuals with Prader-Willi syndrome (PWS) due to uniparental disomy (UPD--where paternally imprinted genes are over-expressed) to individuals with the 15q11-13 deletion form of the syndrome (where paternally imprinted genes are not over-expressed). We also tested reports that PWS cases due to the larger type I (TI) form of deletion show differences to cases with the smaller type II (TII) deletion. METHOD: Ninety-six individuals with PWS were recruited from genetic centres and the PWS association. Forty-nine individuals were confirmed as having maternal UPD of chromosome 15 and were age and sex matched to 47 individuals with a deletion involving 15q11-13 (32 had the shorter (T II) deletion, and 14 had the longer (TI) deletion). Behavioural assessments were carried out blind to genetic status, using the Autism Diagnostic Observation Schedule (ADOS), the Autism Diagnostic Interview (ADI), the Autism Screening Questionnaire (ASQ), the Children's Yale-Brown Obsessive-Compulsive Scale (CY-BOCS), the Vineland Adaptive Behaviour Scales (VABS), and measurements of intellectual ability, including the Wechsler and Mullen Scales and Raven's Matrices. RESULTS: UPD cases exhibited significantly more autistic-like impairments in reciprocal social interaction on questionnaire, interview and standardised observational measures. Comparison of TI and TII deletion cases revealed few differences, but ability levels tended to be lower in the TI deletion cases. CONCLUSIONS: Findings from a large study comparing deletion and UPD forms of Prader-Willi syndrome were consistent with other evidence in indicating that paternally imprinted genes in the 15q11-13 region constitute a genetic risk factor for aspects of autistic symptomatology. These genes may therefore play a role in the aetiology of autism. By contrast with another report, there was no clear-cut relationship between the size of the deletion and the form of cognitive and behavioural phenotype.     

Multiple tumors due to mosaic genome‐wide paternal uniparental disomy

Mosaic genome‐wide paternal uniparental disomy is an infrequently described disorder in which affected individuals have signs and symptoms that may resemble Beckwith–Wiedemann syndrome. In addition, they can develop multiple benign and malignant tumors throughout life. Routine molecular diagnostics may not detect the (characteristic) low level of mosaicism, and the diagnosis is likely to be missed. Genetic counseling and a life‐long alertness for the development of tumors is indicated. We describe the long diagnostic process of a patient who already had a tumor at birth and developed multiple tumors in childhood and adulthood. Furthermore, we offer clues to recognize the entity.     

Genetic abnormalities in Prader-Willi syndrome and lessons from mouse models

Prader-Willi syndrome is a multigenic disorder with developmental and neurobehavioural abnormalities. There are multiple genetic causes, although all ultimately involve the loss of paternally derived gene expression of chromosome region 15q11-q13. Multiple imprinted genes expressed only from the paternal allele have been identified in the specific region of human chromosome 15q associated with Prader-Willi syndrome and in the syntenic mouse chromosome 7C region, including a novel polycistronic gene ( SNURF-SNRPN ) that encodes two independent proteins. The latter genetic locus may play a key role in Prader-Willi syndrome and the evolution of imprinting in this domain, because it is uniquely involved with mutations in the imprinting process and balanced translocations in this syndrome. Indeed, based on the co-localization of SNURF and SNRPN within the imprinting control region critical to Prader-Willi syndrome, evolutionary arguments would suggest that this genetic locus is a prime candidate for mutations producing the failure-to-thrive phenotype of neonates with this syndrome and of corresponding mouse models. Hence the SNURF-SNRPN gene may encode a paternally derived postnatal growth factor.     

Partial cerebellar hypoplasia in a patient with Prader-Willi syndrome

We report a 3-y-old male infant with Prader-Willi syndrome (PWS) caused by a de novo interstitial deletion of 15q11-q13. Additional features included a right cerebellar hemisphere hypoplasia. The extent of deletion was determined by FISH analysis using an SNRPN PW/AS probe that maps in the PWS/AS critical region (CR) and with specific 15q BACs. We unravelled an interstitial 15q11.2-q13.1 deletion spanning about 3 Mb.

Conclusion: To date only a few other PWS patients—including autopsy cases—with CNS structural anomalies have been described. Our case report adds knowledge to the issue of brain involvement in Prader-Willi syndrome. Further MRI studies of PWS patients will be helpful to clarify a correlation between PWS and brain abnormalities.     

Unusual features in children with inv dup(15) supernumerary marker: a study of genotype-phenotype correlation in Taiwan

Recent molecular cytogenetic studies have elucidated the origin and nature of extra structurally abnormal chromosomes (ESACs) or small supernumerary chromosomes, which are often associated with developmental delay and malformations. We studied the prevalence of inv dup(15) in a nationwide screening programme for mentally retarded children in Taiwan and tried to correlate the genotype and phenotype in those patients. Fluorescence in situ hybridization (FISH) analysis using D15Z, D15Z1, and the cosmids from the Prader-Willi/Angelman syndrome chromosome region (PW/ASCR) was performed on 54 patients (0.45%) with ESACs from 11893 probands within a 5-year period. Of them, inv dup(15) was confirmed in 25 children (46.3%) by FISH analysis. The PW/ASCR probes were used to clarify the size and DNA composition of the markers. Patients with inv dup(15) chromosomes, containing only the heterochromatin or little euchromatin of the proximal 15q (i.e., pter→q11:q11→pter) may have a rather mild or nearly normal phenotype (group 1). Only one patient had some features suggestive of Angelman syndrome, but was considered to be a result of deleted (15)(q12) in the chromosome 15 homologue. Additional copies within D15S11 through GABRB3 (15q11.2-13) resulted in an abnormal phenotype which involved mental and developmental delay but was different from the classical phenotype of PW/AS (groups 2, 3). Signs of autistic behavior did occur in each group. FISH combined with microsatellite analyses showed that the marker was often of maternal origin in de novo cases (n = 12, 86%), or inherited from the mother in only one familial case. Down-inv dup(15) was mentioned in two cases. Unusual features including diaphragmatic eventration, hyperlaxity of joints, arachnodactyly, brain atrophy, epilepsy (particularly infantile spasm), ataxia, genital abnormalities, and cleft lip/palate were noted in those patients. This observation expands the range of phenotypic expression associated with this relatively common ESAC. Conclusion Marked phenotypic diversities exist in children with inv dup(15), dependent upon the size or genetic composition of the markers, degree of mosaicism, parental origin and familial occurrence or not. Patients with a larger inv dup(15) marker chromosome including the PW/ASCR may have a higher risk of abnormalities, but not the typical Prade-Willi/Angelman syndrome phenotype. Received: 11 February 1997 and in revised form: 20 May 1997 / Accepted: 20 May 1997     

Laurence-Moon-Biedl syndrome (?) and Prader-Willi syndrome (?) in a single family

Mental retardation, hypogonadism, obesity, and abnormal blood sugar regulation were common findings in two siblings. In addition, the 17-year-old female patient showed short stature, muscular hypotonia in infancy, and small hands with tapering fingers suggesting Prader-Willi syndrome, and the 12-year-old male patient showed retinitis pigmentosa, normal height, and normal muscular tonicity suggesting Laurence-Moon-Biedl syndrome, though polydactyly was absent. Possible consideration was discussed.     

甲基化方法诊断3例Prader-Willi综合征

目的为临床怀疑Prader-Willi综合征（PWS）的患者建立快速准确的分子诊断方法,有利于早期治疗。方法对门诊以肥胖和智力落后就诊的6例患者,根据2001年Meral等提出的临床诊断PWS标准,将3例完全符合临床诊断标准归为高度怀疑组,另3例不完全符合临床诊断标准归为低度怀疑组。用甲基化特异性酶消化患者DNA后,同时扩增15q11．2-13位置SNRPN基因的1号外显子和内参照基因H19。结果3例高度怀疑者均确诊为PWS,均有典型PWS表现,如新生儿期严重肌张力低下,喂养困难,1岁后肌张力好转,食欲增大,肥胖,轻中度智力落后及特殊面容。另3例低度怀疑的患者有智力落后和肥胖,但无新生儿期严重肌张力低下和喂养困难者,排除了PWS诊断。结论甲基化方法结果与临床诊断吻合度高。在临床高度怀疑PWS时,建议用甲基化方法快速确诊,以使患儿能得到及时治疗。     

Fertility in Prader-Willi syndrome: a case report with Angelman syndrome in the offspring

We report on a 32-y-old woman with Prader-Willi syndrome (PWS) and her daughter with Angelman syndrome (AS). PWS in the mother was confirmed as due to a deletion of 15q11-q13, and molecular analysis in the neonate indicated an inherited maternal deletion of the same region. Features of AS in early infancy, such as jerky movements, feeding problems and poor sleep, were observed. At 5 mo of age, a triphasic high voltage EEG pattern was reported. Conclusions: This case confirms the non-Mendelian inheritance of PWS and AS and, in addition to previous reports, provides evidence of fertility in PWS women. We recommend the provision of information regarding fertility in females with PWS to parents, guardians and individuals with PWS, and frequent EEG monitoring for early AS diagnosis. Given the different genetic aetiologies for PWS and AS, cytogenetic and molecular genetic analysis is strongly indicated for counselling and risk estimation.     

Abnormal ventilatory responses in patients with Prader-Willi syndrome

Abnormal ventilatory control in patients with Prader-Willi syndrome when awake and sleeping include abnormal responses to hyperoxia, hypoxia and hypercarbia. Lindgren et al., report similar results regarding response to hypoxia; however, they have demonstrated significant minute ventilation and carbon dioxide responses in their patients treated with growth hormone irrespective of body mass index. It is possible that the explanation for the abnormal respiratory control in this syndrome is located in central rather than peripheral structures. The hypothalamus stands out as the possible location that links their abnormal ventilatory control with the other features. Further investigations to correlate this finding are warranted. Received: 20 April 1999 / Accepted: 21 April 1999     

Segmental uniparental disomy as a rare cause of congenital severe factor XIII deficiency in a girl with only one heterozygous carrier parent

Abstract

Uniparental disomy (UPD) refers to a situation when a person inherits both homologs of a region or complete part of a chromosome from only one parent. Here, we present an unusual case of UPD in congenital severe factor (F) XIII deficiency. A 6-year-old girl experienced cephalhematoma and umbilical bleeding after birth and easy bruising, and postextraction bleeding since early infancy. FXIII activity was 0% [mother 53.7% and father 132.5% (normal 70–140%)] and the FXIII antigen level was 2.5% [mother 38.9% and father 151% (normal 75–155%)]. The washed platelet FXIII activity was 0.1% in the patient (normal 64–144%), suggesting a deficiency of FXIII-A subunit. The FXIII-A subunit genetic analysis detected a homozygous p.Arg382Ser mutation. A similar heterozygous mutation was detected in the mother but surprisingly, not in the father. Kinship was confirmed by a paternity test. To confirm the possibility of UPD, a test using four markers in the vicinity of the F13A1 gene revealed that she inherited duplicate mutations from a heterozygous mutation in her mother, presenting a unique case of unusual maternal segmental UPD in otherwise unexplained congenital (homozygous) severe FXIII deficiency. UPD as a rare cause of autosomal recessive bleeding disorder when only one parent is affected is critical for genetic counseling.     

Growth parameters in maternal uniparental disomy 7 and 14

Introduction Growth retardation has been reported in most cases of maternal uniparental disomy (UPD) 7 and 14, but has never been evaluated in a systematic approach. In this study, an analysis is presented of the auxological data from the literature at birth and on the occasion of the last evaluation of 34 cases with maternal UPD 7 (21 heterodisomy, 13 isodisomy) and 29 cases with maternal UPD 14 (22 heterodisomy, 7 isodisomy). For maternal UPD 7, statistical analysis revealed that length and weight at birth as well as on the occasion of the last evaluation were strongly below average (−2.94 SD and −2.62 SD, and −3.39 SD and −3.11 SD, respectively), whereas at both evaluations occipitofrontal head circumference (OFC) was only slightly below the average (−1.00 SD and −0.85 SD). For maternal UPD 14 at birth, growth retardation is rather concordant for length, weight, and OFC (−2.78 SD, −2.84 SD, and −1.69 SD). Later in life body mass index (BMI) is above average (1.06 SD) and continuously increasing before and after puberty (−0.58 SD and 2.07 SD). Conclusion Growth retardation and relative macrocephaly are of prenatal onset and still present in adults with maternal UPD 7. For patients with maternal UPD 14, growth curves for height, BMI and OFC differ strongly. Genomic imprinting might be a major causative factor, but it seems to function differently for maternal UPD 7 and maternal UPD 14.     

Sudden death in growth hormone-treated children with Prader-Willi syndrome

A 4-year-old boy with Prader-Willi syndrome died suddenly while asleep on day 67 of growth hormone treatment. During treatment, snoring had worsened. Autopsy showed multifocal bronchopneumonia. This case and two others recently published suggest that growth hormone may be associated with obstructive apnea, respiratory infection, and sudden death in this condition.     

Prader-Willi综合征的遗传学研究进展

普拉德-威利综合征(PWS)是一种因为缺乏父源染色体15q11.2-q13区域相关基因的表达而引起的多系统受累的复杂遗传性疾病。其主要遗传机制有3种类型,即父源缺失型、母源单亲二倍体型和印记缺陷型。基于PWS的不同遗传机制可进行遗传咨询,对已生育该病患者的夫妇进行再次生育评估及产前诊断。PWS的致病原因及机制较为复杂,...