Search

Objectives: Kabuki syndrome (KS) is a genetic disorder characterized by intellectual disability, facial dysmorphism and congenital anomalies. We aim to investigate the prenatal features of fetuses with KS and to provide a comprehensive review of the literature on prenatal sonographic abnormalities associated with KS. Methods: We retrospectively reviewed the prenatal ultrasound findings of all mothers of children with molecularly confirmed KS in Hong Kong, between 1991 and 2019. We also performed systematic review of the literature to identify studies on the prenatal findings in KS. Results: We identified 11 cases with KS with detectable fetal ultrasound findings ranging from no detectable abnormalities to a variety of non‐specific findings including increased nuchal translucency, pleural effusion, cardiac anomalies, renal anomalies, intrauterine growth restriction, polyhydramnios, oligohydramnios and single umbilical artery. In combining our cases with the 77 cases published, 42 (50.6%) of them had more than one abnormal antenatal ultrasound finding. The most frequent ultrasound features observed were cardiac anomalies (49.4%), followed by polyhydramnios (28.9%), genitourinary anomalies (26.5%), single umbilical artery (15.7%), intrauterine growth restriction (14.5%) and hydrops fetalis/pleural effusion/ascites (12.0%). Conclusions: These cases demonstrate the prenatal phenotypic heterogeneity associated with KS. Although the ultrasound abnormalities are non‐specific, KS should be considered in the differential diagnosis when these fetal findings following normal microarray analysis/karyotyping. Key points: What's already known about this topic? The anomalies associated with Kabuki syndrome (KS) may be detectable on routine fetal ultrasound. What does this study add?This study provides comprehensive information on the prenatal manifestations of KS. Although the prenatal ultrasound findings are not specific for KS, recognition of the fetal abnormalities should alert clinicians to consider discussion regarding targeted fetal genetic testing using the KS panel or exome sequencing and provision of appropriate counselling to explain the findings. [ABSTRACT FROM AUTHOR]

Kabuki syndrome (OMIM #147920 and 300867) is a rare genetic disorder characterized by a distinctive facial gestalt, intellectual disability and multiple congenital anomalies. We summarized the clinical features and molecular findings of the Kabuki syndrome (KS) patients diagnosed in Hong Kong between January 1991 and December 2019. There were 21 molecularly confirmed KS. Twenty of them were due to pathogenic KMT2D variants and one patient had KDM6A deletion. Nine KMT2D variants were novel. The clinical phenotype of our Chinese KS patients was largely comparable with that reported in patients of other ethnicities. This study expands the mutation spectrum but also provide important natural history information of Chinese KS in literature. [ABSTRACT FROM AUTHOR]

Background Spinocerebellar ataxias (SCAs) are a group of clinically and genetically diverse and autosomal-dominant disorders characterised by neurological deficits in the cerebellum. At present, there is no cure for SCAs. Of the different distinct subtypes of autosomal-dominant SCAs identified to date, causative genes for only a fraction of them are currently known. In this study, we investigated the cause of an autosomal-dominant SCA phenotype in a family that exhibits cerebellar ataxia and pontocerebellar atrophy along with a global reduction in brain volume. Methods and results Whole-exome analysis revealed a missense mutation c.G1391A (p.R464H) in the coding region of the coiled-coil domain containing 88C (CCDC88C) gene in all affected individuals. Functional studies showed that the mutant form of CCDC88C activates the c-Jun N-terminal kinase ( JNK) pathway, induces caspase 3 cleavage and triggers apoptosis. Conclusions This study expands our understanding of the cause of autosomal-dominant SCAs, a group of heterogeneous congenital neurological conditions in humans, and unveils a link between the JNK stress pathway and cerebellar atrophy. [ABSTRACT FROM AUTHOR]

We present the first confirmed case by molecular analysis of a metaphyseal chondrodysplasia, McKusick type, in a 22-week fetus. Two novel compound heterozygous mutations, 64T> A and 79G > T, were found in the highly conserved regions of the RMRP gene. Twenty-two heterozygous g.1018 T> C mutations, two homozygous g.1018 T> C mutations, two heterozygous insertion mutations g.799_g.800insC and one heterozygous insertion mutation g.849_g.850insT were found among 100 normal controls. Careful radiological examination of the fetus for skeletal dysplasia allowed definitive diagnosis, proper genetic counselling and future prenatal diagnosis. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background: Metabolic re-wiring with preferential fatty acid oxidation has been observed in lung cancer cells. Whether the use of trimetazidine, an anti-anginal agent that inhibits fatty acid oxidation, alters clinical outcomes in ischemic heart disease (IHD) patients with lung cancers is unknown., Methods: We carried out this territory-wide, retrospective cohort study of 279,894 IHD patients prescribed with trimetazidine or long-acting oral nitrates in Hong Kong (population coverage of 7.5 millions, January 1999 - December 2020). A total of 6561 patients with pre-existing or de novo lung cancers were identified. Clinical outcomes of all-cause mortality were longitudinally compared between lung cancer patients who received trimetazidine (n = 547) versus non-users (control, n = 6014)., Results: Over 902.9 ± 1410.6 days, lower incidence of deaths occurred in the trimetazidine group (79.0 %, n = 432/547) compared to controls (90.5 %, n = 5442/6014, P < 0.001). Kaplan-Meier analyses showed that trimetazidine use was associated with significantly higher survival from all-cause mortality in IHD patients (trimetazidine: mean survival = 1840.6 [95 %CI 1596.0-2085.3], versus control: 1056.7 [95 %CI 1011.3-1102.0] days, Log Rank = 69.4, P < 0.001). Cox regression showed that trimetazidine use was significantly associated with reduced risk of all-cause mortality in crude (HR = 0.60 [95 %CI: 0.53 to 0.68], P < 0.001) and multivariable models (HR = 0.65 [95 % CI: 0.57 to 0.74], P < 0.001). Pre-specified analyses amongst patients with pre-existing lung cancers yielded similar findings (HR = 0.49 [95 %CI: 0.35 to 0.67], P < 0.001). Survival benefits related to trimetazidine use was predominantly restricted to non-cardiovascular mortality (P < 0.001)., Conclusions: Trimetazidine use is associated with higher overall survival in IHD patients with lung cancers, particularly from non-cardiovascular death. These findings need to be confirmed by randomized controlled trials., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Sizing of FMR1 trinucleotide repeats in the clinical laboratory requires the use of capillary sequencer by PCR, or by a labor intensive measurement using Southern blot method. Our aim was to validate an accurate and robust PCR assay for quantification of CGG repeats., Methods: We performed an analytical and clinical validation of a new PCR-based method that utilizes a low-cost capillary electrophoresis instrument and the FragilEase™ reagent kit. First, analytical performance was demonstrated on 12 Coriell reference samples comprising normal through full mutations. Subsequently, a cohort of 112 archived clinical DNA samples, enriched for premutation and full mutations, was analyzed., Results: All samples were amplified successfully. Quantification of repeat numbers was interpreted by the use of standards with known repeats. Twenty-five full-mutation samples were successfully amplified with the largest allele size measured at 1380 repeats. The repeat numbers from the new assay were concordant with those obtained with the reference method. The intra-assay (CV<2.5%) and inter-assay imprecision was within 1 CGG repeat., Conclusion: This new PCR-based method is reproducible and capable of identifying all Fragile X alleles. It is an accurate and robust method that facilitates Fragile X testing in a broader spectrum of clinical laboratories., (Copyright © 2016 Elsevier B.V. All rights reserved.)

22q11.2 deletion syndrome (22q11.2DS) is a multi-systemic disorder with high phenotypic variability. Under-diagnosis in adults is common and recognition of facial dysmorphic features can be affected by age and ethnicity. This study aims to determine the prevalence of undiagnosed 22q11.2DS in adult Chinese patients with conotruncal anomalies and to delineate their facial dysmorphisms and extra-cardiac manifestations. We recruited consecutively 156 patients with conotruncal anomalies in an adult congenital heart disease (CHD) clinic in Hong Kong and screened for 22q11.2DS using fluorescence-PCR and fluorescence in-situ hybridization. Assessment for dysmorphic features was performed by a cardiologist at initial screening and then by a clinical geneticist upon result disclosure. Clinical photographs were taken and childhood photographs collected. Eighteen patients (11.5%) were diagnosed with 22q11.2DS, translating into 1 previously unrecognized diagnosis of 22q11.2DS in every 10 adult patients with conotruncal anomalies. While dysmorphic features were detected by our clinical geneticist in all patients, only two-thirds were considered dysmorphic by our cardiologist upon first assessment. Evolution of facial dysmorphic features was noted with age. Extra-cardiac manifestations included velopharyngeal incompetence or cleft palate (44%), hypocalcemia (39%), neurodevelopmental anomalies (33%), thrombocytopenia (28%), psychiatric disorders (17%), epilepsy (17%) and hearing loss (17%). We conclude that under-diagnosis of 22q11.2DS in Chinese adults with conotruncal defects is common and facial dysmorphic features may not be reliably recognized in the setting of adult CHD clinic, referral for genetic evaluation and molecular testing for 22q11.2DS should be offered to patients with conotruncal defects., (Copyright © 2014 Elsevier Masson SAS. All rights reserved.)

Despite the advances in the understanding of the molecular basis for oculopharyngeal muscular dystrophy in the last decade, it remains an underdiagnosed disease, especially among the Chinese. In the presence of a positive family history and late-onset ptosis, dysphagia, and proximal muscle weakness (its cardinal features), we suggest that PABPN1 gene analysis should be the first-line investigation to rule out this condition. Muscle biopsy can be reserved for atypical cases. Non-specific mitochondrial changes in the muscle specimens of these patients should be appreciated, so as to avoid diagnostic confusion. It is hoped that greater awareness among medical professionals and judicious use of PABPN1 gene analysis will lead to earlier diagnosis, better management, and avoidance of unnecessary invasive investigations of affected patients.

With the advancement of ophthalmological genetics, the molecular basis for more and more eye diseases can be elucidated. Congenital fibrosis of extraocular muscle (CFEOM) is an example. It is characterised by a congenital non-progressive restrictive ophthalmoplegia and ptosis. It is an autosomal dominant disease, caused by mutations of the KIF21A gene. With positive family history and typical ophthalmological findings, mutational analysis of KIF21A gene should be performed, not only to confirming the diagnosis, but also to offer a prognosis, for genetic counselling, and the possibility of prenatal diagnosis. Here we report the first KIF21A mutation associated with CFEOM1A in Hong Kong.

We report a series of four patients with macrocephaly-capillary malformation (M-CM) who are the first ever reported M-CM patients among Chinese individuals. The salient clinical features and recent diagnostic criteria are discussed. M-CM is a multisystem disease characterized by macrocephaly and cutaneous vascular malformation. Neurodevelopmental abnormalities such as developmental delay, structural brain malformation, and hydrocephalus are common, and thus vigilant clinical and neuroradiological assessment is essential during the first few years of life. Cardiac and tumour surveillance would also be beneficial in selected cases.

Deletions of the distal 3q22.3 region encompassing the gene forkhead transcription factor FOXL2 (FOXL2) usually result in intellectual disability (ID) and the highly recognizable blepharophimosis-ptosis-epicanthus inversus syndrome (BPES). We encountered three patients with molecularly defined interstitial deletions distal to the FOXL2 gene. They present with remarkably similar manifestations comprising variable ID, a coarse facial appearance, including prominent nose and eyebrows, hypogonadism and skin pigmentation abnormalities, and they share an approximately 8.8 Mb overlapping 3q24q25 deletion. Interestingly, one of the present patients was described previously in a clinical report with emphasis on her clinical similarity to the Wisconsin syndrome, suggesting that Wisconsin syndrome might be caused by a (micro) deletion within the 3q24q25 region., (Copyright © 2010 Wiley-Liss, Inc.)

We recently reported on the deficiency of carbohydrate sulfotransferase 3 (CHST3; chondroitin-6-sulfotransferase) in six subjects diagnosed with recessive Larsen syndrome or humero-spinal dysostosis [Hermanns et al. (2008); Am J Hum Genet 82:1368-1374]. Since then, we have identified 17 additional families with CHST3 mutations and we report here on a series of 24 patients in 23 families. The diagnostic hypothesis prior to molecular analysis had been: Larsen syndrome (15 families), humero-spinal dysostosis (four cases), chondrodysplasia with multiple dislocations (CDMD "Megarbane type"; two cases), Desbuquois syndrome (one case), and spondylo-epiphyseal dysplasia (one case). In spite of the different diagnostic labels, the clinical features in these patients were similar and included dislocation of the knees and/or hips at birth, clubfoot, elbow joint dysplasia with subluxation and limited extension, short stature, and progressive kyphosis developing in late childhood. The most useful radiographic clues were the changes of the lumbar vertebrae. Twenty-four different CHST3 mutations were identified; 16 patients had homozygous mutations. We conclude that CHST3 deficiency presents at birth with congenital dislocations of knees, hips, and elbows, and is often diagnosed initially as Larsen syndrome, humero-spinal dysostosis, or chondrodysplasia with dislocations. The incidence of CHST3 deficiency seems to be higher than assumed so far. The clinical and radiographic pattern (joint dislocations, vertebral changes, normal carpal age, lack of facial flattening, and recessive inheritance) is characteristic and distinguishes CHST3 deficiency from other disorders with congenital dislocations such as filamin B-associated dominant Larsen syndrome and Desbuquois syndrome., (Copyright © 2010 Wiley-Liss, Inc.)

Objective: To report a successful case of preimplantation genetic diagnosis (PGD) for Huntington disease using whole genome amplification., Design: Case report., Setting: University assisted reproduction unit., Patient(s): A couple with family history of Huntington disease: The husband was carrying the expanded allele of the IT15 gene, and the wife had the normal allele., Intervention(s): Preimplantation genetic diagnosis with whole genome amplification for identification of genetically normal embryos., Main Outcome Measure(s): Live birth., Result(s): In an IVF cycle, 15 oocytes were retrieved, of which 13 were mature and 11 were fertilized. On day 3, embryo biopsy and PGD were performed on ten good-quality embryos. Multiple displacement amplification was conducted, followed by polymerase chain reaction with fluorescence primers. Three pairs of primers were used for the amplification of the IT15 gene at the: 1) trinucleotide expansion site; 2) trinucleotide expansion site plus the polymorphic site situated on its 3'-end; and 3) polymorphic marker located downstream of the trinucleotide repeats. Two normal blastocysts were replaced on day 5 and another two good-quality blastocysts were cryopreserved. The woman gave birth to a normal baby girl whose normal genetic status was confirmed by prenatal diagnosis., Conclusion(s): Whole genome amplification by multiple displacement amplification can be used for PGD of Huntington disease.

Galactosemia is an inborn error of galactose metabolism, caused by an abnormality in the conversion of galactose and uridine diphosphoglucose to glucose-1-phosphate and uridine diphosphogalactose through the action of 3 sequential enzymes: galactokinase (GALK), galactose- 1-phosphate uridyltransferase (GALT), and uridine phosphogalactose 4-epimerase (GALE). The advent of newborn screening brought hope with early diagnosis and prompt treatment. Newborn screening advocates have pushed for inclusion of galactosemia in the newborn screening panel. However, reports of complications despite early treatment have questioned the merits of universal screening. This paper presents issues in favour and against universal newborn screening for galactosemia.

Purpose: Choroideremia (CHM) is an X-linked retinal degenerative disorder caused by mutations in the CHM gene. The mutations result in malfunction of the Rab escort protein 1 (REP-1). In this study, mutational analysis of the CHM gene was performed on five Chinese families clinically diagnosed with CHM., Methods: Denaturing high performance liquid chromatography was used for mutation screening for all 15 exons and flanking intron regions of the CHM gene. Mutations were confirmed and characterized with DNA sequencing. Second samples were later collected for extraction of mRNA and proteins from leukocytes. A non-radioactive protein truncation test (PTT) was developed and used to characterize the truncating nature of the mutations. Immunoblot analysis of proteins extracted from leukocytes was also performed., Results: Five mutations were identified in these five families, each with one distinct mutation: three frameshift, one nonsense, and one splicing. Two of these were novel mutations: c.627dupA in exon 5 and c.703-1G>C in intron 5. The truncating nature of the mutations was experimentally proved by PTT for four families with second samples collected. In particular, c.703-1G>C spliced exon 5 directly to exon 7 and deleted the entire exon 6 from the transcript. Direct immunoblot analysis failed to detect REP-1 in males affected by CHM, but demonstrated its presence in female carriers and homozygous normal females., Conclusions: This is the first study reporting mutations in the CHM gene in Chinese families. Mutational analysis was performed at the DNA, mRNA and protein levels. Five truncating mutations were found, and two of these were novel.

The present study looks at a paracentric inversion on chromosome 4 [inv(4)(q13;q25)] in members of a large schizophrenia kindred from Hong Kong, and the possibility of a susceptibility gene for schizophrenia at one of the inversion breakpoints. Fluorescence in situ hybridization with BAC and fosmid clones was used to determine the location of the 4q13 and 4q25 breakpoints, however bioinformatic analysis indicated that no known genes are directly disrupted by the breakpoints. We identified several putative genes and expressed sequence tags (ESTs) from around the breakpoint regions, and have characterized them further in order to determine whether they may represent full-length mRNAs that are disrupted by the inversion. Overall, it appears that, while no known genes are disrupted, an as yet undiscovered gene, or indeed, a known gene, may be present near one of the breakpoints and may be disrupted by position effect. We hypothesized that either the 4q13 or 4q25 breakpoint region may contain a common susceptibility gene for schizophrenia. We genotyped 117 schizophrenia families for several short tandem repeat polymorphisms close to the breakpoints. Family based association testing showed no association at the 4q13 breakpoint region, but showed significant allelic association for marker D4S2989 at the 4q25 breakpoint region (p=0.016). This study suggests that the 4q breakpoint regions may harbour a gene that contributes to the illness in the large Hong Kong pedigree, and this 4q25 region should be examined further in other schizophrenia samples.

Objectives: To evaluate the efficacy of Multiplex Ligation-dependent Probe Amplification (MLPA) technique in comparison with the traditional multiplex PCR assay in detection of exon deletions and duplications of the DMD gene., Design and Methods: The sensitivity and accuracy of MLPA were assessed and compared with the multiplex PCR in a total of 63 subjects including 43 subjects with Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD) and 20 female carriers., Results: MLPA was able to detect all the known deletions and duplications; it detected four additional mutations that had been missed by multiplex PCR. In addition, the extent of the deletions and duplications could be more accurately defined which in turn facilitated a genotype-phenotype correlation., Conclusions: MLPA is superior to multiplex PCR. It should be the method of choice for the detection of exon deletions and duplications of the DMD gene in patients with DMD or BMD, as well as in female carriers.

Objectives: To study the AGG interspersion pattern in mentally retarded patients of unspecified cause., Methods: FMR1 CGG substructure in 104 normal and 232 mentally retarded (MR) males was determined by CGG repeat and AGG interspersion analyses. Genomic DNA of the study subjects was obtained for PCR and Southern hybridization analyses., Results: All study subjects had less than 53 CGG repeats and none had fragile X syndrome of mental retardation. There was a significant difference (P < 0.006) in the AGG interspersion pattern. MR males had (1) more variable internal substructures, (2) proportionally less 2 and 3 AGG but more 0 and 1 AGG, less (CGG)(9)AGG(CGG)(9)AGG(CGG)(9) but more (CGG)(9)AGG(CGG)(19) alleles and (3) a longer pure 3' CGG repeat., Conclusions: Our results suggest that the MR alleles have a lesser number of interspersed AGG and a longer pure 3' CGG repeat than the normal population. They are thus more prone to instability and expansion to long repeat lengths as in the fragile X syndrome of mental retardation.

Objectives: (1) To evaluate the prevalence of subtelomeric deletion in moderate to severe mental retardation population, (2) to assess the feasibility and cost-effectiveness of combined methodology in routine workup of this sub-population., Method: Twenty unrelated patients using strict selection criteria were recruited for the study from the Clinical Genetic Service. Patients were initially screened by Multiplex Ligation-dependent Probe Amplification (MLPA) for subtelomeric imbalance followed by FISH analysis for anatomical integrity. This is then followed by parental subtelomeric FISH analysis., Results: Three subtelomeric deletions were identified. They were Deletion 1p36, Deletion 1q44 and Deletion 10q26; these were previously unidentified by conventional technique., Conclusions: The prevalence of subtelomeric deletion in our cohort of moderate to severe mental retardation patients is consistent with published findings of around 10%. The figure is on the higher side if more stringent criteria is used. The combination of strict clinical criteria, MLPA and selective subtelomeric FISH was shown to be feasible and cost-effective.

Background: Sotos syndrome is an overgrowth syndrome with characteristic facial gestalt and mental retardation of variable severity. Haploinsufficiency of the NSD1 gene has been implicated as the major cause of Sotos syndrome, with a predominance of microdeletions reported in Japanese patients. This study was conducted to investigate into the spectrum of NSD1 gene mutations in southern Chinese patients with Sotos syndrome., Methods: Thirty-six Chinese patients with Sotos syndrome and two patients with Weaver syndrome were subject to molecular testing., Results: NSD1 gene mutations were detected in 26 (72%) Sotos patients. Microdeletion was found in only 3 patients, while the other 23 had point mutations (6 frameshift, 8 nonsense, 2 spice site, and 7 missense). Of these, 19 mutations were never reported. NSD1 gene mutations were not found in the two patients with Weaver syndrome., Conclusions: Most cases of Sotos syndrome are caused by NSD1 gene defects, but the spectrum of mutations is different from that of Japanese patients. Genotype-phenotype correlation showed that patients with microdeletions might be more prone to congenital heart disease but less likely to have somatic overgrowth. The two patients with Weaver syndrome were not found to have NSD1 gene mutations, but the number was too small for any conclusion to be drawn.

We report on an 18-week gestation fetus with 46,XX karyotype, gonadal agenesis, meningo-encephalocele, spina bifida, omphalocele, webbing of right upper limb, deformed right clavicle and right sided ribs, absent interventricular septum, hypoplastic aorta, hypoplastic spleen, and single umbilical artery. This case is similar to the one previously described by Kennerknecht et al. in 1997 and may represent a unique syndrome., (Copyright 2003 Wiley-Liss, Inc.)