Journal of pediatric genetics最新文献

The "eye-of-the-tiger" sign in brain magnetic resonance imaging (MRI) is typically associated with neurodegeneration with brain iron accumulation disorders, especially pantothenate kinase-associated neurodegeneration. However, very similar neuroimaging findings may be seen in other neurodegenerative disorders involving the basal ganglia. We report here a patient with fucosidosis who had MRI brain findings closely resembling the "eye-of-the-tiger" sign.

Glutaric aciduria type 1 (GA-1) is a treatable inborn error of metabolism caused by glutaryl-CoA dehydrogenase deficiency. This enzyme deficiency leads to accumulation of glutaric acid, 3-hydroxy glutaric acid, and glutaconic acid which are potentially neurotoxic. Patients with GA-1 have characteristic clinical and neuroimaging features that help us to clinch the diagnosis. Early diagnosis by newborn screening helps us to prevent the motor problems such as dystonia and spasticity. Treatment includes low-protein diet along with carnitine supplementation which may lead to deficiency of essential amino acids and hence malnutrition. Managing malnutrition in a child with inborn errors of metabolism (IEM) is challenging. Here, we describe a patient, a case of GA-1 on medical food, presenting with severe acute malnutrition, who improved with a combination of medical and home-made foods along with lysine-free, tryptophan-reduced amino acid supplements.

Neurofibromatosis type 1 (NF1) is one of the most common inherited disorders. It is caused by mutations in the neurofibromin-1 gene ( NF1 ) and affects the formation and growth of nerve tissues. More than 3,600 pathogenic variants in the NF1 gene have been identified from patients with most of the germline variants are from the Western populations. We found 16 patients (15 Chinese and 1 Asian Indian) who had heterozygous variants in NF1 through targeted next-generation sequencing. There were 15 different variants: 4 frameshift, 4 nonsense, 5 missense, and 2 splice variants. One nonsense variant and three frameshift variants had never been reported in any population or patient database. Twelve of the 16 patients met the NF1 diagnostic criteria, and each was found to have a pathogenic or likely pathogenic variant. Three different missense variants of unknown significance were discovered in the other four patients who did not meet NF1 diagnostic criteria. Our findings add four novel variants to the list of genetic mutations linked to NF1's various clinical manifestations.

Joubert syndrome (JS) is a rare congenital, autosomal recessive disorder characterized by a distinctive brain malformation, developmental delay, ocular motor apraxia, breathing abnormalities, and high clinical and genetic heterogeneity. We are reporting three siblings with JS from consanguineous parents in Syria. Two of them had the same homozygous c.2172delA (p.Trp725Glyfs*) AHI1 mutation and the third was diagnosed prenatally with magnetic resonance imaging. This pathogenic variant is very rare and described in only a few cases in the literature. Multinational collaboration could be of benefit for the patients from undeveloped, low-income countries that have a low-quality health care system, especially for the diagnosis of rare diseases.

Early infantile epileptic encephalopathy-64 (EIEE 64), also called RHOBTB2-related developmental and epileptic encephalopathy (DEE), is caused by heterozygous pathogenic variants (EIEE 64; MIM#618004) in the Rho-related BTB domain-containing protein 2 ( RHOBTB2 ) gene. To date, only 13 cases with RHOBTB2-related DEE have been reported. We add to the literature the 14th case of EIEE 64, identified by whole exome sequencing, caused by a heterozygous pathogenic variant in RHOBTB2 (c.1531C > T), p.Arg511Trp. This additional case supports the main features of RHOBTB2-related DEE: infantile-onset seizures, severe intellectual disability, impaired motor functions, postnatal microcephaly, recurrent status epilepticus, and hemiparesis after seizures.

Hypotonia is a symptom of diminished tone of skeletal muscle and can be nongenetic or a part of genetic syndrome. Hypotonia, developmental delay, and facial dysmorphism are nonspecific findings observed in many genetic syndromes mostly in chromosomal microdeletion and duplication. Here we report a case with severe hypotonia and facial dysmorphism, diagnosed with deletion at 6q13q14.3 by array comparative genomic hybridization (CGH) at very early age. Recent genetic diagnostic technologies such as array CGH may enable clinicians to diagnose chromosomal abnormalities earlier and provide appropriate medical management.

Mutations in SCN2A genes have been described in patients with epilepsy, finding a large phenotypic variability, from benign familial epilepsy to epileptic encephalopathy. To explain this variability, it was proposed the existence of dominant modifier alleles at one or more loci that contribute to determine the severity of the epilepsy phenotype. One example of modifier factor may be the CACNA1G gene, as proved in animal models. We present a 6-day-old male newborn with recurrent seizures in which a mutation in the SCN2A gene is observed, in addition to a variant in CACNA1G gene. Our patient suffered in the first days of life myoclonic seizures, with pathologic intercritical electroencephalogram pattern, requiring multiple drugs to achieve adequate control of them. During the next weeks, the patient progressively improved until complete remission at the second month of life, being possible to withdraw the antiepileptic treatment. We propose that the variant in CACNA1G gene could have acted as a modifier of the epilepsy syndrome produced by the mutation in SCN2A gene in our patient.

Sickle cell anemia (SCA) is a severe disease characterized by anemia, acute clinical complications, and a relatively short life span. In this disease, abnormal hemoglobin makes the red blood cells deformed, rigid, and sticky. Fetal hemoglobin (HbF) is one of the key modulators of SCA morbidity and mortality. Interindividual HbF variation is a heritable trait that is controlled by polymorphism in genes linked and unlinked to the hemoglobin β gene (HBB). The genetic polymorphisms that determine HbF levels are known to ameliorate acute clinical events. About 190 well-characterized homozygous SCA patients were included in this study. Complete blood count (CBC), high-performance liquid chromatography (HPLC), and clinical investigations were obtained from patient's records. Severity scores were determined by using the combination of anemia, complications, total leucocyte count, and transfusion scores. HBG2 rs7482144 polymorphism was genotyped by using the polymerase chain reaction and restriction fragment length polymorphism. The association between HBG2 rs7482144 polymorphism and HbF levels as well as the disease severity of SCA were assessed. SCA patients carrying TT genotype were found to have higher HbF levels. In addition, SCA patients with increased severity showed significantly lower levels of hemoglobin, HbF, and hematocrit values. However, the genotypes of HBG2 rs7482144 polymorphism were not found to be associated with the risk of disease severity. In summary, this study demonstrated that HBG2 rs7482144 polymorphism is linked with HbF levels, but it does not affect disease severity. The sample sizes used and the pattern of association deduced from our small sample size prevents us from extrapolating our findings further.

Acute necrotizing encephalopathy (ANE) is clinically characterized by fever, acute alteration of consciousness, seizures, and rapid progression to coma within days of onset of a viral illness occurring in healthy children without evidence of central nervous system infection. Brain magnetic resonance imaging (MRI) shows multiple symmetrical lesions affecting primarily the thalami but also brain stem, putamina, periventricular white matter, and cerebellum. Most cases of ANE are sporadic and nonrecurrent. However, a missense variant in RANBP2 has been identified in some families with recurrent ANE (OMIM # 608033), also named autosomal dominant ANE (ADANE). Clinical manifestation, clinical course, and brain MRI imaging findings of six affected members of two distinct families with ADANE were described. Sequencing revealed heterozygous c.1754C > T variant in RANBP2 (p.Thr585Met) in affected and asymptomatic family members. Only few ADANE families have been reported and it is the first description in South America. Differential diagnosis of Leigh disease and acute disseminated encephalomyelitis is discussed. Our report reinforces incomplete penetrance of ADANE and intrafamilial phenotypic variability of outcome.

Juvenile open-angle glaucoma (JOAG) is an uncommon subset of primary glaucoma with an onset before the age of 40 years. In this case report, we describe the cosegregation of MYOC , p.Pro370Leu and LTBP2 , p.Pro432Leu mutations in a family with JOAG. The family with autosomal dominant JOAG belonged to Northern India. The samples of proband and her parents were evaluated by whole exome sequencing. Sanger sequencing was conducted in all the study participants to check the mutations identified. Both MYOC and LTBP2 mutations were found to cosegregate in affected individuals leading to a severe JOAG phenotype, thereby suggesting a digenic inheritance of MYOC with LTBP2 in this family.