[Tatton-Brown-Rahman syndrome associated with the DNMT3A gene: a case report and literature review]

This article reports the clinical and genetic features of a case of Tatton-Brown-Rahman syndrome (TBRS) caused by DNMT3A gene mutation. A girl, aged 8 months and 14 days, had the clinical manifestations of psychomotor retardation, hypotonia, ventricular enlargement, and tonsillar hernia malformation. Gene analysis identified a novel heterozygous mutation, c.134C>T(p.A45V), in the DNMT3A gene, and the wild type was observed at this locus in her parents. This mutation was determined as a possible pathogenic mutation according to the guidelines of American College of Medical Genetics and Genomics, which had not been reported in previous studies and conformed to autosomal dominant inheritance. This child was diagnosed with TBRS. TBRS often has a good prognosis, with overgrowth and mental retardation as the most common clinical manifestations, and behavioral and psychiatric problems, scoliosis, and afebrile seizures are possible complications of TBRS. The possibility of TBRS should be considered for children with overgrowth and mental retardation, and genetic diagnosis should be conducted when necessary.

[Ritscher-Schinzel syndrome caused by CCDC22 gene mutation: a case report]

A boy, aged 1 month, attended the hospital due to feeding difficulty and hypotonia. He had unusual facial features (prominent forehead, hypertelorism, ptosis of the lateral canthus, thin upper lip, and low-set ears), hypotonia, and a decreased score of neonatal behavioral neurological assessment. Heart ultrasound showed atrial septal defect. Cranial MRI showed widened supratentorial ventricle, cerebral cistern, and subarachnoid space. High-throughput whole-exome sequencing of the boy detected a hemizygous mutation, c.315_320delTGAGCG, in the CCDC22 gene, which came from his mother, while such mutation was not found in his father. The unusual facies, clinical manifestations, and inheritance pattern of this boy were consistent with the manifestations of Ritscher-Schinzel syndrome reported abroad. This is a report for the first time of a case of X-linked recessive Ritscher-Schinzel syndrome caused by the hemizygous mutation c.315_320delTGAGCG in the CCDC22 gene in Chinese population.

[Autosomal dominant intellectual disability-40 caused by a de novo mutation of the CHAMP1 gene: a case report]

A boy, aged 6 months, had the manifestations of intellectual and motor developmental delay, head instability, general weakness, unawareness of grasping objects by hands, and unusual facies (slightly wide eye distance, epicanthus, esotropia, mouth-opening appearance, short philtrum, and low-set ears). Gene detection results showed a de novo heterozygous frameshift mutation of the CHAMP1 gene at the chromosomal location of chr13:115089847, and nuclear acid was changed to c.530delCinsTTT, resulting in a change in amino acid to p.S177Ffs*2. Therefore, the boy was diagnosed with autosomal dominant intellectual disability-40 caused by the mutation in the CHAMP1 gene. This case report suggests that for children with unexplained intellectual disability, especially those with generalized hypotonia and severe language disorder, the possibility of CHAMP1 gene mutation should be considered, and genetic testing should be performed as early as possible.

[Application of apparent diffusion coefficient in children aged 2-12 years with intellectual disability/global developmental delay who have normal conventional brain MRI findings]

OBJECTIVE

To study the value of fast spin-echo diffusion weighted imaging (TSE-DWI) apparent diffusion coefficient (ADC) in children aged 2-12 years with intellectual disability (ID)/global developmental delay (GDD) who have normal conventional brain MRI findings.

METHODS

A total of 578 children with normal conventional brain MRI findings who met the diagnostic criteria for ID/GDD and 375 normal children were enrolled. Their imaging and clinical data were collected. All children underwent scanning with brain TSE-DWI sequence and routine sequence. ADC values of each brain region were compared between normal children with different ages, as well as between children with different degrees of ID/GDD in each age group. The influence of Adaptive Behavior Assessment System-II (ABAS-II) score on ADC values of each brain region was analyzed.

RESULTS

For the normal children, the ADC values of the frontal and temporal white matter, the corpus callosum, the inner capsule, the centrum semiovale, the cerebellar dentate nucleus, the optic radiation, the thalamus, the lenticular nucleus, and the caudate nucleus gradually decreased with age (P<0.05). ADC values of the deep white matter, the shallow white matter, the deep gray matter nuclei, and the shallow gray matter increased with the increase in the degree of ID/GDD in the ID/GDD children aged 4-6 years (P<0.05). In the children with ID/GDD, the ADC values of the deep white matter, the shallow white matter, and the deep gray matter nuclei decreased with age (P<0.05). The ADC values of the children with ID/GDD decreased with the increase in ABAS-II score (P<0.05).

CONCLUSIONS

ADC can reflect the subtle structural changes of brain regions in children with ID/GDD who have normal conventional brain MRI findings. It may be associated with social adaptation. It can provide an objective basis for the quantitative diagnosis of ID/GDD in children.

[Autism spectrum disorder-like symptoms in the population with intellectual disability aged 6 to 18 years]

OBJECTIVE

To investigate the incidence of autism spectrum disorder (ASD)-like symptoms in the population with intellectual disability (ID).

METHODS

The students with ASD or ID, aged 6-18 years, who studied in a special school in Shanghai from January to June, 2017, as well as the typically developing (TD) population of the same age, who studied in a general school in Shanghai during the same period, were enrolled. Social Responsiveness Scale (SRS) was completed by their parents or other guardians, and the ASD-like symptoms were evaluated.

RESULTS

A total of 69 subjects with ASD, 74 subjects with ID and 177 TD subjects were enrolled. The ID group had a significantly higher SRS-positive rate than the TD group (47.3% vs 1.7%; P<0.001) and a significantly lower SRS-positive rate than the ASD group (47.3% vs 87.0%; P<0.001). The total score of SRS was 114±26 in the ASD group, 80±24 in the ID group and 38±19 in the TD group. The ID group had a significantly higher total score of SRS than the TD group (P<0.05), and the score on the subscale of social cognition showed the most significant difference between the two groups (Cohen's d=2.00). There were no significant differences in the total score of SRS and the scores on each subscale of SRS between the mild-to-moderate ID and severe-to-extremely severe ID groups (P>0.05), and there was no significant correlation between SRS score and IQ (P>0.05).

CONCLUSIONS

The ID population aged 6-18 years has more ASD-like symptoms than the general population, and ASD screening and intervention should be performed for the ID population as early as possible.

一例15号额外标记染色体致智力障碍、难治性癫癎伴中枢性性早熟患者的临床及遗传学分析

Supernumerary marker chromosome 15 is a rare chromosome abnormality. This paper reports the clinical diagnosis and treatment, as well as genetic defects, of a child with supernumerary marker chromosome 15. The patient was a 9.5-year-old girl who had mental and motor retardation since infancy, breast development at the age of 7 years, and seizures at the age of 8.5 years. Seizures occurred with various features and could not be controlled by a variety of antiepileptic drugs. No abnormalities were found by brain magnetic resonance imaging. Electroencephalogram showed frequent epileptiform discharges. G-banding karyotype analysis, fluorescence in situ hybridization, methylation-specific multiplex ligation-dependent probe amplification, and array comparative genomic hybridization identified a de novo 15q duplication in the patient. The maternal copy number increased in the 15q11-13 region. The form of genome rearrangement was 47,XX,+inv dup(15)(pter to q13:q13 to pter). The increased copy number in the 15q11-13 region is closely related to mental retardation, intractable epilepsy, and central precocious puberty. High-resolution karyotype analysis is recommended for children with unexplained mental retardation and epilepsy.

[Psychomotor retardation and intermitent convulsions for 8 months in an infant]

This study reports a boy with psychomotor retardation and epilepsy due to maternal phenylketonuria (PKU). The boy was admitted at the age of 20 months because of psychomotor retardation and epilepsy. He had seizures from the age of 1 year. His development quotient was 43. He presented with microcephaly, normal skin and hair color. Brain MRI scan showed mild cerebral white matter demyelination, broadening bilateral lateral ventricle and foramen magnum stricture. Chromosome karyotype, urine organic acids, blood amino acids and acylcarnitines were normal. His mother had mental retardation from her childhood. She presented with learning difficulties and yellow hair. Her premarriage health examinations were normal. She married a healthy man at age of 26 years. When she visited us at 28 years old, PKU was found by markedly elevated blood phenylalanine (916.54 μmol/L vs normal range 20-120 μmol/L). On her phenylalanine hydroxylase (PAH) gene, a homozygous mutations c.611A>G (p.Y204C) was identified, which confirmed the diagnosis of PAH-deficient PKU. Her child carries a heterozygous mutation c.611A>G with normal blood phenylalanine. Her husband had no any mutation on PAH. It is concluded that family investigation is very important for the etiological diagnosis of the children with mental retardation and epilepsy. Carefully clinical and metabolic survey should be performed for the parents with mental problems to identify parental diseases-associated child brain damage, such as maternal PKU.

[Psychomotor retardation and intermitent convulsions for 8 months in an infant]

This study reports a boy with psychomotor retardation and epilepsy due to maternal phenylketonuria (PKU). The boy was admitted at the age of 20 months because of psychomotor retardation and epilepsy. He had seizures from the age of 1 year. His development quotient was 43. He presented with microcephaly, normal skin and hair color. Brain MRI scan showed mild cerebral white matter demyelination, broadening bilateral lateral ventricle and foramen magnum stricture. Chromosome karyotype, urine organic acids, blood amino acids and acylcarnitines were normal. His mother had mental retardation from her childhood. She presented with learning difficulties and yellow hair. Her premarriage health examinations were normal. She married a healthy man at age of 26 years. When she visited us at 28 years old, PKU was found by markedly elevated blood phenylalanine (916.54 μmol/L vs normal range 20-120 μmol/L). On her phenylalanine hydroxylase (PAH) gene, a homozygous mutations c.611A>G (p.Y204C) was identified, which confirmed the diagnosis of PAH-deficient PKU. Her child carries a heterozygous mutation c.611A>G with normal blood phenylalanine. Her husband had no any mutation on PAH. It is concluded that family investigation is very important for the etiological diagnosis of the children with mental retardation and epilepsy. Carefully clinical and metabolic survey should be performed for the parents with mental problems to identify parental diseases-associated child brain damage, such as maternal PKU.