Clinical and genetic analysis of two children with Neurodevelopmental disorder with hypotonia, stereotypic hand movements, and impaired language due to de novo variants of MEF2C gene / 中华医学遗传学杂志

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.

Genetic analysis and prenatal diagnosis of a child with Multiple congenital malformations-hypotonia-epilepsy syndrome type 3 due to variants of PIGT gene / 中华医学遗传学杂志

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.

Clinical and genetic analyses of Joubert syndrome in children / 中国当代儿科杂志

OBJECTIVES@#To study the clinical and genetic features of Joubert syndrome (JS) in children.@*METHODS@#A retrospective analysis was performed on the clinical data, genetic data, and follow-up data of 20 children who were diagnosed with JS in the Department of Children's Rehabilitation, the Third Affiliated Hospital of Zhengzhou University, from January 2017 to July 2022.@*RESULTS@#Among the 20 children with JS, there were 11 boys and 9 girls. The common clinical manifestations were developmental delay (20 children, 100%), abnormal eye movement (19 children, 95%), and hypotonia (16 children, 80%), followed by abnormal respiratory rhythm in 5 children (25%) and unusual facies (including prominent forehead, low-set ears, and triangular mouth) in 3 children (15%), and no limb deformity was observed. All 20 children (100%) had the typical "molar tooth sign" and "midline cleft syndrome" on head images, and 6 children (30%) had abnormal eye examination results. Genetic testing was performed on 7 children and revealed 6 pathogenic genes, i.e., the CPLANE1, RPGRIP1L, MKS1, CC2D2A, CEP120, and AHI1 genes.@*CONCLUSIONS@#For children with developmental delay, especially those with abnormal eye movement and hypotonia, it is recommended to perform a head imaging examination to determine the presence or absence of "molar tooth sign" and "midline cleft syndrome", so as to screen for JS to avoid missed diagnosis and misdiagnosis. There are many pathogenic genes for JS, and whole-exome sequencing can assist in the diagnosis of JS.

Clinical characteristics of four children with 3M syndrome and a literature review / 中华医学遗传学杂志

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.

The First Korean Patient with Potocki-Shaffer Syndrome: A Rare Cause of Multiple Exostoses

Potocki-Shaffer syndrome (PSS, OMIM #601224) is a rare contiguous gene deletion syndrome caused by haploinsufficiency of genes located on the 11p11.2p12. Affected individuals have a number of characteristic features including multiple exostoses, biparietal foramina, abnormalities of genitourinary system, hypotonia, developmental delay, and intellectual disability. We report here on the first Korean case of an 8-yr-old boy with PSS diagnosed by high resolution microarray. Initial evaluation was done at age 6 months because of a history of developmental delay, hypotonia, and dysmorphic face. Coronal craniosynostosis and enlarged parietal foramina were found on skull radiographs. At age 6 yr, he had severe global developmental delay. Multiple exostoses of long bones were detected during a radiological check-up. Based on the clinical and radiological features, PSS was highly suspected. Subsequently, chromosomal microarray analysis identified an 8.6 Mb deletion at 11p11.2 [arr 11p12p11.2 (Chr11:39,204,770-47,791,278)x1]. The patient continued rehabilitation therapy for profound developmental delay. The progression of multiple exostosis has being monitored. This case confirms and extends data on the genetic basis of PSS. In clinical and radiologic aspect, a patient with multiple exostoses accompanying with syndromic features, including craniofacial abnormalities and mental retardation, the diagnosis of PSS should be considered.

The First Korean Patient with Potocki-Shaffer Syndrome: A Rare Cause of Multiple Exostoses

Potocki-Shaffer syndrome (PSS, OMIM #601224) is a rare contiguous gene deletion syndrome caused by haploinsufficiency of genes located on the 11p11.2p12. Affected individuals have a number of characteristic features including multiple exostoses, biparietal foramina, abnormalities of genitourinary system, hypotonia, developmental delay, and intellectual disability. We report here on the first Korean case of an 8-yr-old boy with PSS diagnosed by high resolution microarray. Initial evaluation was done at age 6 months because of a history of developmental delay, hypotonia, and dysmorphic face. Coronal craniosynostosis and enlarged parietal foramina were found on skull radiographs. At age 6 yr, he had severe global developmental delay. Multiple exostoses of long bones were detected during a radiological check-up. Based on the clinical and radiological features, PSS was highly suspected. Subsequently, chromosomal microarray analysis identified an 8.6 Mb deletion at 11p11.2 [arr 11p12p11.2 (Chr11:39,204,770-47,791,278)x1]. The patient continued rehabilitation therapy for profound developmental delay. The progression of multiple exostosis has being monitored. This case confirms and extends data on the genetic basis of PSS. In clinical and radiologic aspect, a patient with multiple exostoses accompanying with syndromic features, including craniofacial abnormalities and mental retardation, the diagnosis of PSS should be considered.

Novel mutation in MCT8 gene in a Brazilian boy with thyroid hormone resistance and severe neurologic abnormalities / Mutação nova do gene MCT8 em menino Brasileiro com resistência ao hormônio tireioidiano e neuropatia grave

O MCT8 é um transportador celular de hormônios tireoidianos, importante para sua ação e metabolização. Relatamos o caso de um menino com a nova mutação inativadora 630insG no éxon 1 do MCT8. O paciente caracterizou-se por grave comprometimento neurológico (inicialmente com hipotonia global, evoluindo com hipertonia generalizada), crescimento normal nos dois primeiros anos de vida, reduzido ganho ponderal e ausência dos sinais e sintomas típicos de hipotireoidismo. A sua avaliação sérica revelou elevação do T3, redução do T4 total e livre e TSH levemente aumentado. O tratamento com levotiroxina melhorou o perfil hormonal tireoidiano, mas não modificou o quadro clínico do paciente. Esses dados reforçam o conceito de que o papel do MCT8 é tecido-dependente: enquanto os neurônios são altamente dependentes do MCT8, o osso, o tecido adiposo, o músculo e o fígado são menos dependentes do MCT8 e, portanto, podem sofrer as consequências da exposição a níveis séricos elevados de T3.

MCT8 is a cellular transporter of thyroid hormones important in their action and metabolization. We report a male patient with the novel inactivating mutation 630insG in the coding region in exon 1 of MCT8. He was characterized clinically by severe neurologic impairment (initially with global hypotonia, later evolving with generalized hypertonia), normal growth during infancy, reduced weight gain, and absence of typical signs and symptoms of hypothyroidism, while the laboratory evaluation disclosed elevated T3, low total and free T4, and mildly elevated TSH serum levels. Treatment with levothyroxine improved thyroid hormone profile but was not able to alter the clinical picture of the patient. These data reinforce the concept that the role of MCT8 is tissue-dependent: while neurons are highly dependent on MCT8, bone tissue, adipose tissue, muscle, and liver are less dependent on MCT8 and, therefore, may suffer the consequences of the exposition to high serum T3 levels.

X-linked Myotubular Myopathy in a Family with Two Infant Siblings: A Case with MTM1 Mutation

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.

MRI findings in Joubert syndrome.

Joubert syndrome is a very rare autosomal recessive disorder with only 200 cases reported worldwide.Here we report 4 cases of this rare disorder with MRI findings.

Allan-Herndon-Dudley syndrome.

Allan-Herndon-Dudley Syndrome (AHDS) is a rare X-linked disorder caused by mutation in the gene encoding the monocarboxylate transporter-8. Abnormal transport function is reflected by elevated free T3 and decreased free T4 levels along with clinical features characterized by neurological abnormalities including global developmental delay, central hypotonia, rotatory nystagmus, impaired hearing, spasticity and contractures of joints. We report a child with classical clinical features along with confirmatory deranged thyroid levels in blood.