Phenotype of Takayasu-like vasculitis and cardiopathy in patients with Blau syndrome.

OBJECTIVES: We aimed to determine the prevalence of cardiovascular involvement in our Blau syndrome (BS) cohort and provide detailed analysis of their cardiovascular manifestations and outcome. We also tried to find out the risk factors for developing cardiovascular involvement. METHODS: Clinical manifestations, laboratory findings, and treatments were reviewed. Clinical features were compared between children with cardiovascular involvement and those without angiocardiopathy. RESULTS: A total of 38 BS children were eligible for final analysis. Among them, 13 (34.2%) developed Takayasu-like vasculitis and/or cardiopathy. Compared with those without angiocardiopathy, recurrent fever was more frequent in BS patients with cardiovascular involvement (p < 0.001). What is more, tumor necrosis factor alpha antagonists (anti-TNF) were more urgently needed in children with cardiovascular involvement (p = 0.015). BS patients with cardiovascular involvement include 4 with Takayasu-like vasculitis and 9 with cardiopathy. The onset of cardiovascular manifestations ranged from 0.75 to 18.5 years of age, with most cases occurring before school period. Symptoms were elusive and lacked specificity, such as dizziness, short of breath, and edema. Some patients were even identified because of the unexpected hypertension during follow-up. Cardiopathy and vasculitis occurred in patients with different genotypes. Imaging changes were discovered before the presentation of the typical triad in 3/4 patients with Takayasu-like vasculitis. Three children developed left ventricular dysfunction with decreased left ventricular ejection fraction. Combination of glucocorticoids and methotrexate with anti-TNF agents is a common treatment option for these BS patients. In the cohort, BS-related cardiovascular involvement was controlled well, with cardiac structural and functional abnormalities completely recovered and slower progression of vasculitis lesions. CONCLUSION: Cardiovascular manifestations is not rare in BS patients. Because of its insidious onset, a systematic and comprehensive assessment of cardiovascular involvement should be performed in newly diagnosed patients with BS. Aggressive initiation of anti-TNF agents may be beneficial to improve the prognosis. Key Points • About 34.2% patients with Blau syndrome developed Takayasu-like vasculitis and/or cardiopathy. • Compared with those without angiocardiopathy, recurrent fever and application of anti-TNF agents were more frequent in BS patients with cardiovascular involvement (p < 0.001, p = 0.015) • Regular assessment of cardiovascular involvement is extremely necessary because of its insidious onset.

[Application of a low copper diet guidance based on food exchange portions in children with hepatolenticular degeneration]. / åŸºäºŽé£Ÿç‰©äº¤æ¢ä»½æ³•çš„ä½Žé“œé¥®é£ŸæŒ‡å¯¼åœ¨è‚è±†çŠ¶æ ¸å˜æ€§æ‚£å„¿ä¸­çš„åº”ç”¨æ•ˆæžœ.

OBJECTIVES: To study the efficacy of a low-copper diet guidance based on food exchange portions in children with hepatolenticular degeneration. METHODS: A self-controlled study was conducted from July 2021 to June 2022, including 30 children under the age of 18 who were diagnosed with hepatolenticular degeneration and poorly controlled with a low-copper diet. During the medical visit, personalized low-copper diet guidance was provided to the children and their parents using a copper-containing food exchange table and a copper food exchange chart. During home care, compliance with the low-copper diet of the children was improved by recording dietary diaries and conducting regular follow-ups. The changes in 24-hour urine copper level, liver function indicators, and the low-copper diet knowledge of the children's parents were observed before and after the intervention, with no change in the original drug treatment. RESULTS: After 8, 16, and 24 weeks of intervention, the 24-hour urine copper level decreased significantly compared to before intervention (P<0.05). When compared to 8-week intervention, the urine copper level decreased significantly after 16 and 24 weeks of intervention. The 24-hour urine copper level after 24 weeks of intervention decreased significantly compared to 16 weeks of intervention (P<0.05).After 24 weeks of intervention, the alanine aminotransferase and aspartate aminotransferase levels decreased significantly compared to before intervention (P<0.05). Additionally, in 16 of the cases (53%), alanine aminotransferase and aspartate aminotransferase returned to normal levels. Following 8 weeks of intervention, the low-copper diet knowledge of the children's parents increased significantly (P<0.05). CONCLUSIONS: A low-copper diet guidance based on food exchange portions can effectively decrease the urine copper level and improve liver function in children with hepatolenticular degeneration. Furthermore, it can increase the low-copper diet knowledge of the children's parents.

Use of IDEAL-IQ in Quantifying Femoral Bone Marrow Involvement in Gaucher Disease.

OBJECTIVE: To quantitatively measure femoral bone marrow involvement in patients with Gaucher disease (GD) by using fat fraction (FF) derived from the iterative decomposition of water and fat with echo asymmetry and least-squares estimation quantitation (IDEAL-IQ) technique. METHODS: Bilateral femora of 23 patients with type 1 GD receiving low-dose imiglucerase treatment were prospectively scanned using structural magnetic resonance imaging sequences and an IDEAL-IQ sequence. Femoral bone marrow involvement was evaluated by both semiquantification (bone marrow burden [BMB] score based on magnetic resonance imaging structural images) and quantification (FF derived from IDEAL-IQ) methods. These patients were further divided into subgroups according to whether they underwent splenectomy or had bone complications. The interreader agreement of measurements and the correlation between FF and clinical status were statistically analyzed. RESULTS: In patients with GD, both BMB and FF evaluation of femora showed good interreader concordance (intraclass correlation coefficient = 0.98 and 0.99, respectively), and FF highly correlated with BMB score ( P < 0.001). The longer the duration of disease, the lower the FF ( P = 0.026). Femoral FF was lower in subgroups with splenectomy or bone complications than those without splenectomy or bone complications (0.47 ± 0.08 vs 0.60 ± 0.15, 0.51 ± 0.10 vs 0.61 ± 0.17, respectively, both P < 0.05). CONCLUSION: Femoral FF derived from IDEAL-IQ could be used to quantify femoral bone marrow involvement in patients with GD, and low bone marrow FF may predict worse outcomes of GD patients in this small-scale study.

Case report: Multiple arterial stenoses induced by autosomal-recessive hypophosphatemic rickets type 2 associated with mutation of ENPP1: a case study.

Ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1)-related multiple arterial stenoses is a rare clinical syndrome in which global arterial calcification begins in infancy, with a high probability of early mortality, and hypophosphatemic rickets develops later in childhood. The vascular status of an ENPP1-mutated patient when they enter the rickets phase has not been thoroughly explored. In this study, we presented a case of an adolescent with an ENPP1 mutation who complained of uncontrolled hypertension. Systematic radiography showed renal, carotid, cranial, and aortic stenoses as well as random calcification foci on arterial walls. The patient was incorrectly diagnosed with Takayasu's arteritis, and cortisol therapy had little effect on reducing the vascular stenosis. As a result, phosphate replacement, calcitriol substitution, and antihypertensive medication were prescribed, and the patient was discharged for further examination. This research presented the vascular alterations of an ENPP1-mutanted patient, and while there is less calcification, intimal thickening may be the primary cause of arterial stenosis.

Unique mutation spectrum of progressive pseudorheumatoid dysplasia in the Chinese population: a retrospective genotype-phenotype analysis of 105 patients.

BACKGROUND: Progressive pseudorheumatoid dysplasia (PPRD) is a rare genetic disease with autosomal recessive inheritance. There was a lack of genotype-phenotype correlation data from the Chinese population. This study aimed to identify the genotype and phenotype characteristics of Chinese PPRD patients and to conduct a genotype-phenotype analysis of Chinese PPRD patients. METHODS: Genetic analysis was performed for suspected PPRD patients from Peking Union Medical College Hospital. Medical records were collected from the electronic medical record system and patient-held portable health records. Published Chinese PPRD cases were gathered from both international and Chinese local databases. We collected demographic information, genetic variants, clinical manifestations, and imaging characteristics for further analysis. RESULTS: We included 105 Chinese PPRD patients in the current study. Thirty-three variants, including nine novels and five hotspot variants, were identified, with 26/33 (79%) variants exclusively seen in the Chinese population. Chinese PPRD patients share a phenotype similar to that in international reports. Joint involvement may progress with age (R2 = 0.2541). Long bone shortening and severe deformities occur in three patients with biallelic null variants, of which at least one variant is located in exon 2. Among hotspot variants, c.624dupA (p.C209Mfs*21) were associated with later onset and more involved joints. Elbow joints were more likely to be affected in patients carrying c.624dupA (p.C209Mfs*21) and c.866dupA (p.S209Efs*13). Shoulder joints are more likely to be involved in patients with biallelic null variants (P = 0.027). CONCLUSIONS: Chinese PPRD patients share a unique mutation spectrum. Among the five hotspot variants, c.624dupA is associated with later onset of disease, more extensive joint involvement, and a tendency to affect elbow joints. Biallelic null variants with at least one variant in exon 2 could be a likely cause of long bone shortening and severe deformities.

Phenotypic and genetic characteristics of 130 patients with mucopolysaccharidosis type II: A single-center retrospective study in China.

Background: Mucopolysaccharidosis Type II (MPS II) is a rare, progressive and ultimately fatal X-linked lysosomal storage disorder caused by mutations in the iduronate-2-sulfatase (IDS) gene. This report conducted a retrospective analysis to investigate the clinical characteristics, genotypes and management strategies in a large cohort of Chinese patients with MPS II. Methods: In this study, we explored 130 Chinese patients with MPS II between September 2008 and April 2022. Clinical manifestations, auxiliary examination, IDS pathogenic gene variants and IDS enzyme activity, surgical history were analysed in the study. Results: A total of 130 patients were enrolled and the mean age at diagnosis was 5 years old. This study found the most common symptoms in our patients were claw-like hands, followed by coarse facial features, birthmarks (Mongolian spot), delayed development, inguinal or umbilical hernia. The most commonly cardiac manifestations were valve abnormalities, which were mitral/tricuspid valve regurgitation (71.9%) and aortic/pulmonary valve regurgitation (36.8%). We had found 43 different IDS pathogenic gene variants in 55 patients, included 16 novel variants. The variants were concentrated in exon 9 (20% = 11/55), exon 3 (20% = 11/55) and exon 8 (15% = 8/55). A total of 50 patients (38.5%) underwent surgical treatment, receiving a total of 63 surgeries. The average age of first surgery was 2.6 years, and the majority of surgery (85.7%, 54/63) was operated before 4 years old. The most common and earliest surgery was hernia repair. Three patients were died of respiratory failure. Conclusion: This study provided additional information on the clinical, cardiac ultrasound and surgical procedure in MPS II patients. Our study expanded the genotype spectrum of MPS II. Based on these data, characterization of MPS II patients group could be used to early diagnosis and treatment of the disease.

Early recombinant human growth hormone treatment improves mental development and alleviates deterioration of motor function in infants and young children with Prader-Willi syndrome.

BACKGROUND: Recombinant human growth hormone (rhGH) therapy has shown to improve height and body composition in children with Prader-Willi syndrome (PWS), the evidence of early rhGH treatment on motor and mental development is still accumulating. This study explored the time effect on psychomotor development, anthropometric indexes, and safety for infants and young children with PWS. METHODS: A phase 3, single-arm, multicenter, self-controlled study was conducted in six sites. Patients received rhGH at 0.5 mg/m2/day for first four weeks, and 1 mg/m2/day thereafter for up to 52 weeks. Motor development was measured using Peabody Developmental Motor Scales-second edition, mental development using Griffiths Development Scales-Chinese (GDS-C). Height standard deviation score (SDS), body weight SDS, and body mass index (BMI) SDS were also assessed. RESULTS: Thirty-five patients were enrolled totally. Significant improvements were observed in height, body weight, and BMI SDS at week 52; GDS-C score showed significant improvement in general quotient (GQ) and sub-quotients. In a linear regression analysis, total motor quotient (TMQ), gross motor quotient (GMQ), and fine motor quotient were negatively correlated with age; however, treatment may attenuate deterioration of TMQ and GMQ. Changes in GQ and locomotor sub-quotient in < 9-month group were significantly higher than ≥ 9-month group. Mild to moderate severity adverse drug reactions were reported in six patients. CONCLUSION: Fifty-two-week treatment with rhGH improved growth, BMI, mental development, and lessened the deterioration of motor function in infants and young children with PWS. Improved mental development was more pronounced when instituted in patients < 9 months old.

Clinical features of gout in adult patients with type Ia glycogen storage disease: a single-centre retrospective study and a review of literature.

BACKGROUND: This study aimed to explore the clinical features of gout in adult patients with glycogen storage disease type Ia (GSD Ia). METHODS: Ninety-five adult patients with GSD Ia admitted to Peking Union Medical College Hospital were retrospectively analysed. A clinical diagnosis of GSD Ia was confirmed in all patients through gene sequencing. All patients had hyperuricaemia; 31 patients complicated with gout were enrolled, and 64 adult GSD Ia patients with asymptomatic hyperuricaemia were selected as a control group during the same period. Clinical characteristics were analysed and compared between the two groups. RESULTS: Thirty-one of the 95 patients had complications of gout (median age, 25 years; 11 (35.5%) females). All 31 patients had hepatomegaly, abnormal liver function, fasting hypoglycaemia, hyperuricaemia, hyperlipaemia, and hyperlacticaemia. A protuberant abdomen, growth retardation, recurrent epistaxis, and diarrhoea were the most common clinical manifestations. Among these 31 patients, 10 patients (32.3%) had gout as the presenting manifestation and were diagnosed with GSD Ia at a median time of 5 years (range, 1-14) after the first gout flare. The median age of gout onset was 18 years (range, 10-29). Fifteen of the 31 GSD Ia-related gout patients were complicated with gouty tophi, which has an average incidence time of 2 years after the first gouty flare. The mean value of the maximum serum uric acid (SUA) was 800.5 µmol/L (range, 468-1068). The incidence of gout in adult GSD Ia patients was significantly associated with the initial age of regular treatment with raw corn starch, the proportion of urate-lowering therapy initiated during the asymptomatic hyperuricaemic stage, maximum SUA level, and mean cholesterol level. CONCLUSIONS: Determination of GSD Ia should be performed for young-onset gout patients with an early occurrence of gouty tophi, especially in patients with hepatomegaly, recurrent hypoglycaemia, or growth retardation. Early detection and long-term regulatory management of hyperuricaemia, in addition to early raw corn starch and lifestyle intervention, should be emphasized for GSD Ia patients in order to maintain good metabolic control. TRIAL REGISTRATION: Retrospectively registered.

A novel MAGED2 variant in a Chinese preterm newborn with transient antenatal Bartter's syndrome with 4 years follow-up.

BACKGROUND: Transient antenatal Bartter's syndrome caused by MAGED2 mutation is a rare X-linked recessive renal tubular disorder. Cases reported are mostly infants, and the long-term prognosis of the disease is still under investigation. CASE PRESENTATION: We encountered a preterm male infant with polyhydramnios, polyuria, salt loss, hypercalciuria, nephrocalcinosis and alkalosis. Antenatal Bartter's syndrome was suspected, but these clinical symptoms surprisingly disappeared after about 2 months. This led to the clinical diagnosis of transient antenatal Bartter's syndrome. Gene analysis in this patient disclosed a novel variant (c.1598C > T, p.Ala533Val) in exon 12 of MAGED2 gene, and his mother was a heterozygous carrier. This patient was followed up in clinic for 4 years without recurrence of imbalance of potassium, sodium and chloride. His height and weight were in normal range, and all laboratory examinations and nephrotic ultrasound were also normal. CONCLUSIONS: We reported the first Chinese case of transient antenatal Bartter's syndrome caused by MAGED2 mutation. The 4-year follow-up of our case further demonstrates the benign prognosis of the disease and indicates that early recognition of this phenotype could avoid unnecessary treatments.

Separation in genetic pathogenesis of mutations in FBN1-TB5 region between autosomal dominant acromelic dysplasia and Marfan syndrome.

Mutations in the transforming growth factor ß-binding protein-like domain 5 (TB5) region of FBN1 can lead to autosomal acromelic dysplasia and Marfan syndrome, which are two diseases with apparently opposite phenotypes. We identified six patients with acromelic dysplasia carrying either the previously reported mutations c.5284G > A (p.Gly1762Ser) and c.5096A > G (p.Tyr1699Cys) or the novel mutation c.5260G > A (p.Gly1754Ser). A systematic review of patients with mutations in the FBN1-TB5 region showed that acromelic dysplasia is caused only by in-frame amino acid substitutions. In contrast, truncating mutations in the FBN1-TB5 have been reported only in Marfan syndrome. Acromelic dysplasia subtypes that share symptoms with Marfan syndrome are associated with FBN1-TB5 disulfide disruptions, which are also commonly found in Marfan syndrome. These results suggest that the type and location of mutations in the FBN1-TB5 region determine the clinical spectrum of fibrillinopathy.

Farber disease in a patient from China.

Farber disease (FD) is a rare lysosomal storage disorder caused by mutation of the ASAH1 gene. Classic symptoms of FD include subcutaneous nodules, joint pain and hoarseness. Most patients die during childhood. Here we report a 25-year-old female FD patient with rare osteolytic changes of bilateral hands and toes. Genetic analysis revealed novel compound heterozygous mutations in the ASAH1 gene (c.427T>G and c.358G>C). Further research is needed to elucidate the pathophysiological course.

Exonic rearrangements in DMD in Chinese Han individuals affected with Duchenne and Becker muscular dystrophies.

Exonic deletions and duplications within DMD are the main pathogenic variants in Duchenne and Becker muscular dystrophies (DMD/BMD). However, few studies have profiled the flanking sequences of breakpoints and the potential mechanism underlying the breakpoints in different fragile regions of DMD. In this study, 896 Chinese male probands afflicted with DMD/BMD were selected from unrelated families and analyzed using multiplex ligation-dependent probe amplification of the DMD gene, in which we identified exon deletions in 784 subjects and duplications in 112 subjects. Deletions occurred most frequently in the genomic region encompassing exons 45-55, accounting for 73% of all deletion patterns. Furthermore, to unravel the potential mechanism that induced breaks, DMD gene capture and sequencing were performed to identify the breakpoints in 37 subjects with deletions encompassing exons 45-55 of DMD; we found that DMD instability did not arise from a single cause; instead, long-sequence motifs, nonconsensus microhomologies, low-copy repeats, and microindels were embedded around the breakpoints, which may predispose DMD to instability. In summary, this study highlights the heterogeneous characteristics of the flanking sequences around the breakpoints and helps us to understand the mechanism underlying DMD gene instability.

Characteristics of Pompe disease in China: a report from the Pompe registry.

BACKGROUND: Pompe disease is a rare, progressive, autosomal recessive lysosomal storage disorder caused by mutations in the acid α-glucosidase gene. This is the first report of Chinese patients from the global Pompe Registry. Chinese patients enrolled in the Registry ( ClinicalTrials.gov , NCT00231400) between Jan 2013 and 2 Sep 2016 with late onset Pompe disease (LOPD; presentation after 12 months of age or presentation at ≤12 months without cardiomyopathy) were included. Data analyses were descriptive. RESULTS: Of the 59 Chinese patients included, 86.4% had never received enzyme replacement therapy (ERT). The age at symptom onset and diagnosis was 14.9 (12.35) and 22.1 (10.08) years, which is younger than previous reports of LOPD patients from the rest of the world (28.4 [18.86] and 34.9 [20.03], respectively). The most common diagnosis methods were enzyme assay (79.7%) and/or DNA analysis (61.0%). Of the 36 patients diagnosed using DNA analysis, 31 had standardized variant data and among these patients the most common mutations were c.2238G > C (n = 18, 58.1%) and c.2662G > T (n = 5, 16.1%). Chinese LOPD patients appeared to have worse lung function versus patients from the rest of the world, indicated by lower forced vital capacity (37.2 [14.00]% vs. 63.5 [26.71]%) and maximal expiratory and inspiratory pressure (27.9 [13.54] vs. 51.0 [38.66] cm H2O, and 29.4 [12.04] vs. 70.5 [52.78] cm H2O). CONCLUSIONS: Compared with patients from the rest of the world, Chinese patients with LOPD appeared to have younger age at symptom onset and diagnosis, lower lung function, and the majority had not received ERT. The most common mutations were c.2238G > C and c.2662G > T.

Eosinophilic meningitis caused by Angiostrongylus cantonensis in an infant: A case report.

RATIONALE: Parasitic eosinophilic meningitis is rarely observed in infants. The diagnosis of this disease is complicated by its atypical and severe clinical manifestations. PATIENT CONCERNS: An infant presented to our hospital with high fever and irritability, as well as refusal to walk. Cerebrospinal fluid collected through lumbar puncture showed increased eosinophil count and third-stage Angiostrongylus cantonensis larvae. DIAGNOSES: Eosinophilic meningitis was suspected. INTERVENTIONS: We started empiric treatment with levamisole (14 mg bid, 2.5 mg/kg·day) and prednisone (17.5 mg qd, 1.5 mg/kg·day). OUTCOMES: All of the infant's symptoms were resolved approximately 72 hours after treatment. The patient fully recovered from her illness after completing 4 weeks of levamisole and prednisolone treatment. LESSONS: A. cantonensis is the most common cause of parasitic eosinophilic meningitis cases in Southeast Asia. Physicians treating infants who live in areas where A. cantonensis is endemic and who present with irritability, abnormal motor function, and elevated eosinophil count should be aware of the disease to provide timely and rational therapy to the patients.

[Discussion on the standard of clinical genetic testing report and the consensus of gene testing industry].

The widespread application of next generation sequencing (NGS) in clinical settings has enabled testing, diagnosis, treatment and prevention of genetic diseases. However, many issues have arisen in the meanwhile. One of the most pressing issues is the lack of standards for reporting genetic test results across different service providers. The First Forum on Standards and Specifications for Clinical Genetic Testing was held to address the issue in Shenzhen, China, on October 28, 2017. Participants, including geneticists, clinicians, and representatives of genetic testing service providers, discussed problems of clinical genetic testing services across in China and shared opinions on principles, challenges, and standards for reporting clinical genetic test results. Here we summarize expert opinions presented at the seminar and report the consensus, which will serve as a basis for the development of standards and guidelines for reporting of clinical genetic testing results, in order to promote the standardization and regulation of genetic testing services in China.

Clinical and genetic characteristics of 17 Chinese patients with glycogen storage disease type IXa.

Glycogen storage disease (GSD) type IXa is caused by PHKA2 mutation, which accounts for about 75% of all the GSD type IX cases. Here we first summarized the clinical data and analyzed the PHKA2 gene of 17 Chinese male patients suspected of having GSD type IXa. Clinical symptoms of our patients included hepatomegaly, growth retardation, and liver dysfunction. The clinical and biochemical manifestations improved and even disappeared with age. We detected 14 mutations in 17 patients, including 8 novel mutations; exons 2 and 4 were hot spots in this research. In conclusion, glycogen storage disease type IXa is a mild disorder with a favorable prognosis, and there was no relationship between genotype and phenotype of this disease.

Rare Loss-of-Function Variants in NPC1 Predispose to Human Obesity.

Some Shanghai Clinical Center f a role of Niemann-Pick type C1 (NPC1) for obesity traits. However, whether the loss-of-function mutations in NPC1 cause adiposity in humans remains unknown. We recruited 25 probands with rare autosomal-recessive Niemann-Pick type C (NP-C) disease and their parents in assessment of the effect of heterozygous NPC1 mutations on adiposity. We found that male NPC1+/- carriers had a significantly higher BMI than matched control subjects or the whole population-based control subjects. Consistently, male NPC1+/- mice had increased fat storage while eating a high-fat diet. We further conducted an in-depth assessment of rare variants in the NPC1 gene in young, severely obese subjects and lean control subjects and identified 17 rare nonsynonymous/frameshift variants in NPC1 (minor allele frequency <1%) that were significantly associated with an increased risk of obesity (3.40% vs. 0.73%, respectively, in obese patients and control subjects, P = 0.0008, odds ratio = 4.8, 95% CI 1.7-13.2), indicating that rare NPC1 variants were enriched in young, morbidly obese Chinese subjects. Importantly, participants carrying rare variants with severely damaged cholesterol-transporting ability had more fat accumulation than those with mild/no damage rare variants. In summary, rare loss-of-function NPC1 mutations were identified as being associated with human adiposity with a high penetrance, providing potential therapeutic interventions for obesity in addition to the role of NPC1 in the familial NP-C disease.

Mutation Analysis of 16 Mucolipidosis II and III Alpha/Beta Chinese Children Revealed Genotype-Phenotype Correlations.

Mucolipidosis II and III alpha/beta are autosomal recessive diseases caused by mutations in the GNPTAB gene which encodes the α and ß subunits of the N-acetylglucosamine-1-phosphotransferase. Clinically, mucolipidosis II (MLII) is characterized by severe developmental delay, coarse facial features, skeletal deformities, and other systemic involvement. In contrast, MLIII alpha/beta is a much milder disorder, the symptoms of which include progressive joint stiffness, short stature, and scoliosis. To study the relationship between the genotypes and phenotypes of the MLII and MLIII alpha/beta patients, we analyzed the GNPTAB gene in 16 Chinese MLII and MLIII alpha/beta patients. We collected and analyzed the patients' available clinical data and all showed clinical features typical of MLII or MLIII alpha/beta. Moreover, the activity of several lysosomal enzymes was measured in the plasma and finally the GNPTAB gene was sequenced. We detected 30 mutant alleles out of 32 alleles in our patients. These include 10 new mutations (c.99delC, c.118-1G>A, c.523_524delAAinsG, c.1212C>G, c.2213C>A, c.2345C>T, c.2356C>T, c.2455G>T, c.2821dupA, and c.3136-2A>G) and 5 previously reported mutations (c.1071G>A, c.1090C>T, c.2715+1G>A, c.2550_2554delGAAA, and c.3613C>T). The most frequent mutation was the splicing mutation c.2715+1G>A, which accounted for 28% of the mutations. The majority of the mutations reported in the Chinese patients (57%) were located on exon 13 or in its intronic flanking regions.

Spectrum of AGL mutations in Chinese patients with glycogen storage disease type III: identification of 31 novel mutations.

Glycogen storage disease type III (GSD III), a rare autosomal recessive disease characterized by hepatomegaly, fasting hypoglycemia, growth retardation, progressive myopathy and cardiomyopathy, is caused by deficiency of the glycogen debranching enzyme (AGL). Direct sequencing of human AGL cDNA and genomic DNA has enabled analysis of the underlying genetic defects responsible for GSD III. To date, the frequent mutations in different areas and populations have been described in Italy, Japan, Faroe Islands and Mediterranean area, whereas little has been performed in Chinese population. Here we report a sequencing-based mutation analysis in 43 Chinese patients with GSD III from 41 families. We identified 51 different mutations, including 15 splice-site (29.4%), 11 small deletions (21.6%), 12 nonsense (23.5%), 7 missense (13.7%), 5 duplication (9.8%) and 1 complex deletion/insertion (2.0%), 31 of which are novel mutations. The most common mutation is c.1735+1G>T (11.5%). The association of AGL missense and small in-frame deletion mutations with normal creatine kinase level was observed. Our study extends the spectrum of AGL mutations and suggests a genotype-phenotype correlation in GSD III.