OBJECTIVE: To analyze the clinical features of 3M syndrome and effect of growth hormone therapy. METHODS: Clinical data of four children diagnosed with 3M syndrome by whole exome sequencing at Hunan Children's Hospital from January 2014 to February 2022 were retrospectively analyzed, which included clinical manifestation, results of genetic testing and recombinant human growth hormone (rhGH) therapy. A literature review was also carried our for Chinese patients with 3M syndrome. RESULTS: The clinical manifestations of the 4 patients included severe growth retardation, facial dysmorphism and skeletal malformations. Two patients were found to harbor homozygous variants of CUL7 gene, namely c.4717C>T (p.R1573*) and c.967_993delinsCAGCTGG (p.S323Qfs*33). Two patients were found to harbor 3 heterozygous variants of the OBSL1 gene including c.1118G>A (p.W373*), c.458dupG (p.L154Pfs*1002) and c.690dupC (p.E231Rfs*23), among which c.967_993delinsCAGCTGG and c.1118G>A were unreported previously. Eighteen Chinese patients with 3M syndrome were identified through the literature review, including 11 cases (11/18, 61.1%) carrying CUL7 gene variants and 7 cases (7/18, 38.9%) carrying OBSL1 gene variants. The main clinical manifestations were in keeping with previously reported. Four patients were treated with growth hormone, 3 showed obvious growth acceleration, and no adverse reaction was noted. CONCLUSION 3M syndrome has a typical appearance and obvious short stature. To attain accurate diagnosis, genetic testing should be recommended for children with a stature of less than -3 SD and facial dysmorphism. The long-term efficacy of growth hormone therapy for patients with 3M syndrome remains to be observed.
Humans ; Child ; Retrospective Studies ; Dwarfism/genetics* ; Muscle Hypotonia/genetics* ; Growth Hormone/therapeutic use* ; Cytoskeletal Proteins/genetics*

OBJECTIVE: To explore the clinical characteristics and genetic etiology for two children with Neurodevelopmental disorder with hypotonia, stereotypic hand movements, and impaired language (MEDHSIL). METHODS: Two children who had visited the Ningbo Women and Children's Hospital on October 15, 2021 were selected as the study subjects. Whole exome sequencing (WES) was carried out for both patients. Candidate variants were verified by Sanger sequencing of their family members. RESULTS: The two children were respectively found to harbor a heterozygous c.138delC (p.Ile47Serfs*42) variant and a c.833del (p.L278*) variant of the MEF2C gene. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), both variants were predicted to be pathogenic (PVS1+PS2+PM2_Supporting). CONCLUSION The c.138delC and c.833del variants of the MEF2C gene probably underlay the pathogenesis of MEDHSIL in the two children. Above findings have enriched the mutational spectrum of the MEF2C gene and enabled genetic counseling for their families.
Child ; Humans ; Family ; Genetic Counseling ; Language ; MEF2 Transcription Factors/genetics* ; Muscle Hypotonia/genetics* ; Neurodevelopmental Disorders

OBJECTIVE: To explore the clinical features and genetic basis of a child with Galactosemia. METHODS: A child who had presented at the Children's Hospital Affiliated to Zhengzhou University on November 20, 2019 was selected as the study subject. Clinical data of the child was collected. Whole exome sequencing was carried out for the child. Candidate variants were validated by Sanger sequencing. RESULTS: Clinical manifestations of the child have included anemia, feeding difficulty, jaundice, hypomyotonia, abnormal liver function and coagulation abnormality. Tandem mass spectrometry showed increased citrulline, methionine, ornithine and tyrosine. Urine organic acid analysis showed increased phenyllactic acid, 4-hydroxyphenylacetic acid, 4-hydroxyphenyllactic acid, 4-hydroxyphenylpyruvate and N-acetyltyrosine. Genetic testing revealed that the child has harbored compound heterozygous variants of the GALT gene, namely c.627T>A (p.Y209*) and c.370G>C (p.G124R), which were respectively inherited from her healthy parents. Among these, c.627T>A (p.Y209*) was known as a likely pathogenic variant, while c.370G>C (p. G124R) was unreported previously and also predicted as a likely pathogenic variant(PM1+PM2_Supporting+PP3_Moderate+PPR). CONCLUSION Above discovery has expanded the spectrum of the GALT gene variants underlying Galactosemia. Patients with thrombocytopenia, feeding difficulties, jaundice, abnormal liver function and coagulation abnormality without obvious causes should be analyzed by screening of metabolic diseases in combination with genetic testing.
Child ; Female ; Humans ; Galactosemias/genetics* ; Genetic Testing ; Health Status ; Methionine ; Muscle Hypotonia ; Mutation

OBJECTIVE: To explore the clinical features and genetic etiology of a child with Multiple congenital malformations-hypotonia-epilepsy syndrome type 3 (MCAHS3) and provide prenatal diagnosis for her parents. METHODS: A female child who had presented at Linyi People's Hospital on 27 July 2022 for recurrent convulsions for over 4 years was selected as the study subject. Clinical data of the child were collected. Peripheral blood samples were taken from the child and her parents and subjected for whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing. Prenatal diagnosis was carried out on amniotic fluid sample at 18 weeks' gestation. Bioinformatic software was used to analyze the pathogenicity of the protein model for the variant loci. RESULTS: The child was a 4-year-old female with frequent seizures, peculiar facial appearance, hypotonia and severe developmental delay. Genetic analysis revealed that she has harbored compound heterozygous variants of the PIGT gene, namely c.1126del (p.H376Tfs*56) and c.1285G>C (p.E429Q), which were respectively inherited from her mother and father. Based on the guidelines from the American College of Medical Genetics and Genomics, the c.1126del (p.H376Tfs*56) variant was predicted to be pathogenic (PVS1+PM2_Supporting+PM4), and c.1285G>C (p.E429Q) variant was predicted to be likely pathogenic (PM2_Supporting+PM3+PM4). Prenatal diagnosis suggested that the fetus also harbored the same compound heterozygous variants, and the pregnancy was terminated with induced labor. CONCLUSION The c.1126del (p.H376Tfs*56) and c.1285G>C (p.E429Q) compound heterozygous variants of the PIGT gene probably underlay the MCAHS3 in this patient, and prenatal diagnosis has prevented birth of further affected child in this family.
Humans ; Female ; Child ; Pregnancy ; Child, Preschool ; Muscle Hypotonia/genetics* ; Prenatal Diagnosis ; Computational Biology ; Epileptic Syndromes ; Facies

OBJECTIVE: To explore the genetic basis for a child featuring hypotonia, ataxia, and delayed development syndrome (HADDS). METHODS: Whole exome sequencing was carried out for the child. Candidate variant was verified by Sanger sequencing of the child and his parents. RESULTS: The child was found to harbor a de novo heterozygous c.625G>A (p.Arg209Trp) variant of the EBF3 gene, which has caused substitution of Arginine by Tryptophan. The variant may has impaired the binding affinity of EBF3 with DNA and altered its subcellular localization, and ultimately decreased the transcriptional activity of the EBF3 gene. CONCLUSION The c.625G>A variant of the EBF3 gene probably underlay the pathogenesis of HADDS in this child. Above finding has expanded the spectrum of EBF3 variants and enriched the clinical manifestations of the HADDS.
Child ; Humans ; Ataxia/genetics* ; Intellectual Disability/genetics* ; Muscle Hypotonia/genetics* ; Mutation ; Syndrome ; Transcription Factors/genetics* ; Exome Sequencing ; Male

X-linked myotubular myopathy (XLMTM) is a rare congenital muscle disorder, caused by mutations in the MTM1 gene. Affected male infants present severe hypotonia, and generalized muscle weakness, and the disorder is most often complicated by respiratory failure. Herein, we describe a family with 2 infants with XLMTM which was diagnosed by gene analysis and muscle biopsy. In both cases, histological findings of muscle showed severely hypoplastic muscle fibers with centrally placed nuclei. From the family gene analysis, the Arg486STOP mutation in the MTM1 gene was confirmed.
*Codon, Nonsense ; Humans ; Male ; Muscle Hypotonia/genetics/pathology ; Myopathies, Structural, Congenital/*genetics/pathology ; Pedigree ; Protein Tyrosine Phosphatases, Non-Receptor/*genetics

OBJECTIVE: To analyze the clinical and genetic characteristics of a child featuring Xia-Gibbs syndrome. METHODS: Whole exome sequencing was carried out for the child. RESULTS: The patient has presented with developmental delay, hypotonia, strabismus and snoring. Cranial MRI revealed hypomyelination, while the EEGs were normal. Genetic testing revealed a de novo variant of the AHDC1 gene, namely c.730delA (p.Ile244Serfs*16), which was classified as pathogenic (PVS1+PS2+PM2). Together with 60 cases from the literature, individuals harboring a AHDC1 variant commonly have delayed motor milestones, speech delay, facial dysmorphism and hypotonia. Dysgenesis of corpus callosum is also common. In total 47 AHDC1 variants have been reported, among which truncating variants were the most common type. CONCLUSION The c.730delA (p.Ile244Serfs*16) variant of the AHDC1 gene probably underlay the Xia-Gibbs syndrome in this patient. Above finding has provided a basis for the clinical diagnosis.
Abnormalities, Multiple/genetics* ; Child ; DNA-Binding Proteins/genetics* ; Humans ; Intellectual Disability/genetics* ; Muscle Hypotonia ; Mutation ; Whole Exome Sequencing

More than 100 genes located on the X chromosome have been found to be associated with X-linked intellectual disability (XLID) to date, and NEXMIF is a pathogenic gene for XLID. In addition to intellectual disability, patients with NEXMIF gene mutation can also have other neurological symptoms, such as epilepsy, abnormal behavior, and hypotonia, as well as abnormalities of other systems. Two children with intellectual disability and epilepsy caused by NEXMIF gene mutation were treated in the Department of Pediatrics, Xiangya Hospital, Central South University from March 8, 2017 to June 20, 2020. Patient 1, a 7 years and 8 months old girl, visited our department because of the delayed psychomotor development. Physical examination revealed strabismus (right eye), hyperactivity, and loss of concentration. Intelligence test showed a developmental quotient of 43.6. Electroencephalogram showed abnormal discharge, and cranial imaging appeared normal. Whole exome sequencing revealed a de novo heterozygous mutation, c.2189delC (p.S730Lfs*17) in the NEXMIF gene (NM_001008537). During the follow-up period, the patient developed epileptic seizures, mainly manifested as generalized and absent seizures. She took the medicine of levetiracetam and lamotrigine, and the seizures were under control. Patient 2, a 6-months old boy, visited our department due to developmental regression and seizures. He showed poor reactions to light and sound, and was not able to raise head without aid. Hypotonia was also noticed. The electroencephalogram showed intermittent hyperarrhythmia, and spasms were monitored. He was given topiramate and adrenocorticotrophic hormone (ACTH). Whole exome sequencing detected a de novo c.592C>T (Q198X) mutation in NEXMIF gene. During the follow-up period, the seizures were reduced with vigabatrin. He had no obvious progress in the psychomotor development, and presented strabismus. There were 91 cases reported abroad, 1 case reported in China, and 2 patients were included in this study. A total of 85 variants in NEXMIF gene were found, involving 83 variants reported in PubMed and HGMD, and the 2 new variants presented in our patients. The patients with variants in NEXMIF gene all had mild to severe intellectual disability. Behavioral abnormalities, epilepsy, hypotonia, and other neurological symptoms are frequently presented. The phenotype of male partially overlaps with that of female. Male patients often have more severe intellectual disability, impaired language, and autistic features, while female patients often have refractory epilepsy. Most of the variants reported so far were loss-of-function resulted in the reduced protein expression of NEXMIF. The degree of NEXMIF loss appears to correlate with the severity of the phenotype.
Child ; Epilepsy/genetics* ; Female ; Humans ; Intellectual Disability/genetics* ; Male ; Muscle Hypotonia/complications* ; Mutation ; Phenotype ; Seizures/genetics* ; Strabismus/complications*

Objective: To explore the clinical features of hepatocerebral mitochondrial DNA depletion syndrome (MDS). Methods: The clinical data of 6 hepatocerebral MDS patients diagnosed in the Jinshan Hospital of Fudan University from January 2012 to December 2019 were retrospectively collected and analyzed. Related literature published before January 2020 were searched with the key words of "DGUOK""MPV17""POLG""C10orf2" in PubMed, China national knowledge infrastructure (CNKI) and Wanfang database. Results: All the 6 hepatocerebral MDS cases were male. The age of onset ranged from 3 days to 8 months. The most common initial symptoms were cholestasis and developmental retrogression. The main clinical manifestations included hepatomegaly (4 cases), hypotonia (3 cases), growth retardation (4 cases), cholestasis (5 cases), coagulopathy (5 cases), hypoalbuminemia (3 cases), hypoglycemia (4 cases), hyperlactacidemia (5 cases), and abnormal blood metabolism screening (6 cases). The isotope hepatobiliary imaging revealed no gallbladder and intestinal tract development within 24 hours in 2 patients. Regarding the cranial imaging examination, the head CT found widening of the extracranial space in 1 case, the brain magnetic resonance imaging (MRI) found ventricular enlargement in 2 cases, and the brain ultrasound found peripheral white matter injury in 1 case. Two cases were lost to follow-up, one died of liver failure, and three died of multiple organ failure due to aggravated infection. Among the 6 cases, there were 3 with MPV17 variation (c.182T>C and c.279G>C were novel), 1 with POLG variation (c.2993G>A was novel), 1 with DGUOK variation (c.679G>A homozygous mutation, parthenogenetic diploid of chromosome 2) and 1 with C10orf2 variation (c.1186C>T and c.1504C>T were novel). The literature review found that 129, 100, 51 and 12 cases of hepatocerebral MDS were caused by DGUOK, MPV17, POLG and C10orf2 gene variations, respectively. And the most common clinical manifestations were liver dysfunction presented with cholestasis and elevated transaminase, metabolic disorders including hypoglycemia and hyperlactacidemia, and diverse neurologic symptoms including developmental retardation, hypotonia, epilepsy and peripheral neuropathy. Besides, 1/3 of the patients with C10orf2 variation developed renal tubular injury. Conclusions: Hepatocerebral MDS mainly present with liver dysfunction, metabolic disorder and neuromuscular impairment. Different genotypes show specific clinical manifestations.
Cholestasis ; DNA, Mitochondrial/genetics* ; Female ; Humans ; Hypoglycemia/genetics* ; Infant ; Liver Diseases/genetics* ; Male ; Mitochondrial Diseases ; Muscle Hypotonia ; Retrospective Studies

A 15-day-old boy was admitted to the hospital due to repeated convulsions for 14 days. The main clinical manifestations were uncontrolled seizures, hypoergia, feeding difficulties, limb hypotonia, and bilateral hearing impairment. Clinical neurophysiology showed reduced brainstem auditory evoked potential on both sides and burst-suppression pattern on electroencephalogram. Measurement of very-long-chain fatty acids in serum showed that C26:0 was significantly increased. Genetic testing showed a pathogenic compound heterozygous mutation, c.101C>T(p.Ala34Val) and c.1448_1460del(p.Ala483Aspfs*37), in the
Genetic Testing ; Humans ; Infant, Newborn ; Male ; Muscle Hypotonia ; Mutation ; Peroxisomal Multifunctional Protein-2/genetics* ; Protein Deficiency/genetics*