Evaluation of the Patients with the Diagnosis of Pontocerebellar Hypoplasia: A Multicenter National Study.

Pontocerebellar hypoplasia (PCH) is a heterogeneous group of neurodegenerative disorders characterized by hypoplasia and degeneration of the cerebellum and pons. We aimed to identify the clinical, laboratory, and imaging findings of the patients with diagnosed PCH with confirmed genetic analysis. We collected available clinical data, laboratory, and imaging findings in our retrospective multicenter national study of 64 patients with PCH in Turkey. The genetic analysis included the whole-exome sequencing (WES), targeted next-generation sequencing (NGS), or single gene analysis. Sixty-four patients with PCH were 28 female (43.8%) and 36 (56.3%) male. The patients revealed homozygous mutation in 89.1%, consanguinity in 79.7%, pregnancy at term in 85.2%, microcephaly in 91.3%, psychomotor retardation in 98.4%, abnormal neurological findings in 100%, seizure in 63.8%, normal biochemistry and metabolic investigations in 92.2%, and dysmorphic findings in 51.2%. The missense mutation was found to be the most common variant type in all patients with PCH. It was detected as CLP1 (n = 17) was the most common PCH related gene. The homozygous missense variant c.419G > A (p.Arg140His) was identified in all patients with CLP1. Moreover, all patients showed the same homozygous missense variant c.919G > T (p.A307S) in TSEN54 group (n = 6). In Turkey, CLP1 was identified as the most common causative gene with the identical variant c.419G > A; p.Arg140His. The current study supports that genotype data on PCH leads to phenotypic variability over a wide phenotypic spectrum.

Bi-allelic truncating variants in CASP2 underlie a neurodevelopmental disorder with lissencephaly.

Lissencephaly (LIS) is a malformation of cortical development due to deficient neuronal migration and abnormal formation of cerebral convolutions or gyri. Thirty-one LIS-associated genes have been previously described. Recently, biallelic pathogenic variants in CRADD and PIDD1, have associated with LIS impacting the previously established role of the PIDDosome in activating caspase-2. In this report, we describe biallelic truncating variants in CASP2, another subunit of PIDDosome complex. Seven patients from five independent families presenting with a neurodevelopmental phenotype were identified through GeneMatcher-facilitated international collaborations. Exome sequencing analysis was carried out and revealed two distinct novel homozygous (NM_032982.4:c.1156delT (p.Tyr386ThrfsTer25), and c.1174 C > T (p.Gln392Ter)) and compound heterozygous variants (c.[130 C > T];[876 + 1 G > T] p.[Arg44Ter];[?]) in CASP2 segregating within the families in a manner compatible with an autosomal recessive pattern. RNA studies of the c.876 + 1 G > T variant indicated usage of two cryptic splice donor sites, each introducing a premature stop codon. All patients from whom brain MRIs were available had a typical fronto-temporal LIS and pachygyria, remarkably resembling the CRADD and PIDD1-related neuroimaging findings. Other findings included developmental delay, attention deficit hyperactivity disorder, hypotonia, seizure, poor social skills, and autistic traits. In summary, we present patients with CASP2-related ID, anterior-predominant LIS, and pachygyria similar to previously reported patients with CRADD and PIDD1-related disorders, expanding the genetic spectrum of LIS and lending support that each component of the PIDDosome complex is critical for normal development of the human cerebral cortex and brain function.

Biallelic hypomorphic mutations in HEATR5B, encoding HEAT repeat-containing protein 5B, in a neurological syndrome with pontocerebellar hypoplasia.

HEAT repeats are 37-47 amino acid flexible tandem repeat structural motifs occurring in a wide variety of eukaryotic proteins with diverse functions. Due to their ability to undergo elastic conformational changes, they often serve as scaffolds at sites of protein interactions. Here, we describe four affected children from two families presenting with pontocerebellar hypoplasia manifest clinically with neonatal seizures, severe intellectual disability, and motor delay. Whole exome sequencing identified biallelic variants at predicted splice sites in intron 31 of HEATR5B, encoding the HEAT repeat-containing protein 5B segregating in a recessive fashion. Aberrant splicing was found in patient fibroblasts, which correlated with reduced levels of HEATR5B protein. HEATR5B is expressed during brain development in human, and we failed to recover live-born homozygous Heatr5b knockout mice. Taken together, our results implicate loss of HEATR5B in pontocerebellar hypoplasia.

Exome sequencing can improve diagnosis and alter patient management.

The translation of "next-generation" sequencing directly to the clinic is still being assessed but has the potential for genetic diseases to reduce costs, advance accuracy, and point to unsuspected yet treatable conditions. To study its capability in the clinic, we performed whole-exome sequencing in 118 probands with a diagnosis of a pediatric-onset neurodevelopmental disease in which most known causes had been excluded. Twenty-two genes not previously identified as disease-causing were identified in this study (19% of cohort), further establishing exome sequencing as a useful tool for gene discovery. New genes identified included EXOC8 in Joubert syndrome and GFM2 in a patient with microcephaly, simplified gyral pattern, and insulin-dependent diabetes. Exome sequencing uncovered 10 probands (8% of cohort) with mutations in genes known to cause a disease different from the initial diagnosis. Upon further medical evaluation, these mutations were found to account for each proband's disease, leading to a change in diagnosis, some of which led to changes in patient management. Our data provide proof of principle that genomic strategies are useful in clarifying diagnosis in a proportion of patients with neurodevelopmental disorders.

The effects of antiepileptic drugs on the relationships between leptin levels and bone turnover in prepubertal children with epilepsy.

Antiepileptic drugs (AED) had an effect on bone metabolism in children. This study was conducted in order to determine the relationships between serum leptin levels, bone mineral density (BMD) and bone turnover markers in epileptic children. Fifty-three patients were treated with valproic acid (VPA) and 23 with carbamazepine (CBZ) monotherapy; 50 healthy children were included in the study as controls. Serum alkaline phosphatase (ALP) and cross-linked C-telopeptide (CTx) levels were statistically significantly higher in the CBZ group than in the VPA group and the control group (p < 0.0001, p < 0.010, respectively). Serum osteocalcin and ALP levels were significantly lower in the VPA group than in the control group (P < 0.012, P < 0.030, respectively). Although we found slightly higher serum leptin levels in both the CBZ and VPA groups, they were not significantly different from the control group (P > 0.05). We demonstrated that the markers of bone formation and resorption increased with CBZ and decreased with VPA treatment without affecting BMD and vitamin D levels in prepubertal epileptic children.

Tracing immature myelin in acute disseminated encephalomyelitis.

Inherent abnormalities of myelin have been suggested in the pathogenesis of multiple sclerosis (MS). We investigated myelin in acute disseminated encephalomyelitis (ADEM) patients by magnetic resonance spectroscopy (MRS) and cerebrospinal fluid (CSF) analysis for citrulline, a marker of immature myelin. A citrulline peak was observed in the normal appearing white matter of 7/15 patients and of 1/10 age-matched neurological controls (p=0.08). CSF citrulline was elevated in 4/6 patients. Alterations in the composition of myelin might predispose to or follow acute inflammatory disorders of the central nervous system.

Henoch-Schönlein purpura in north-eastern Turkey.

AIM: To evaluate the epidemiological and clinical findings in children with Henoch-Schönlein purpura (HSP) admitted during a 10-year period, 1995 to 2004, and to compare them with series from other parts of the world. METHODS: The medical records of all children aged 17 years or less admitted with a diagnosis of HSP to the Department of Pediatrics of Karadeniz Technical University were evaluated retrospectively for epidemiological and clinical features. RESULTS: Of 116 children, 73 (63%) were boys. The mean (SD) age at presentation was 8.9 (3.7) years and one-third of them were older than 10 years of age. Over half the cases presented between September and January. All patients had the typical skin rash. Gastro-intestinal manifestations were seen in 64 (55.1%) and joint manifestations, common during the early course of the disease, in 73 (62.9%). Two patients required laparatomy, one for acute abdomen and the other for bowel resection owing to intussusception. Renal manifestations were observed in 36 (31%), all within 3 months of initial symptoms, and one patient (0.8%) with nephritic syndrome progressed to end-stage renal disease. Five patients had hypertension without urinary findings. Symptoms recurred in eight patients (6.9%) over a period ranging from 2 to 5 months after complete resolution of symptoms. There was a history of a preceding upper respiratory tract infection in 16 (13.7%) and a streptococcal infection was confirmed by throat culture in 12 of the 42 (28.5%) children at presentation. CONCLUSION: HSP is generally benign and self-limiting. Hypertension may be seen during the course of the disease without urinary findings. In this area, it seems to affect older children and there is a relatively lower incidence of renal manifestations.