PRKACA-related, atrial defects-polydactyly-multiple congenital malformation syndrome in an Indian patient.

PRKACA-related, atrial defects-polydactyly-multiple congenital malformation syndrome is a recently described skeletal ciliopathy, which is caused by disease-causing variants in PRKACA. The primary phenotypic description includes atrial septal defects, and limb anomalies including polydactyly and short limbs. To date, only four molecularly proven patients have been reported in the literature with a recurrent variant, c.409G>A p.Gly137Arg in PRKACA. In this study, we report the fifth affected individual with the same variant and review the clinical features and radiographic findings of this rare syndrome.

Patient Tailored Surgery in Saethre-Chotzen Syndrome: Analysis of Reoperation for Intracranial Hypertension.

Saethre-Chotzen syndrome (SCS) is a syndromic craniosynostosis with pathogenic variants in the TWIST1 gene showing a broad phenotypic spectrum. Controversies exist in the literature regarding surgical management with single one-stage versus patient-tailored surgery and the related reoperation rate for intracranial hypertension of up to 42%. At our center, SCS patients are offered patient-tailored surgery with single-stage fronto-orbital advancement and remodeling or fronto-orbital advancement and remodeling and posterior distraction in an individually determined order. The authors' database identified 35 confirmed SCS patients between 1999 and 2022. Involved sutures in craniosynostosis were left unicoronal (22.9%), bicoronal (22.9%), sagittal (8.6%), bicoronal and sagittal (5.7%), right unicoronal (2.9%), bicoronal and metopic (2.9%), bicoronal, sagittal and metopic (2.9%), and bilateral lambdoid (2.9%). There was pansynostosis in 8.6% and no craniosynostosis in 14.3% of the patients. Twenty-six patients, 10 females, and 16 males were operated on. Mean age at the first surgery was 1.70 years, and 3.86 years at the second surgery. Eleven of 26 patients had invasive intracranial pressure monitoring. Three patients presented with papilledema before the first surgery and 4 afterward. Four of the 26 operated patients were operated initially elsewhere. The other 22 patients were initially referred to our unit and underwent patient-tailored surgery. Nine of these patients (41%) had a second surgery, and 3 (14%) of them were because of raised intracranial pressure. Seven (27%) of all operated patients had a complication. Median follow-up was 13.98 years (range, 1.85-18.08). Patient-tailored surgery in a specialized center and long-term follow-up allow for a low reoperation rate for intracranial hypertension.

Deficiency of TET3 leads to a genome-wide DNA hypermethylation episignature in human whole blood.

TET3 encodes an essential dioxygenase involved in epigenetic regulation through DNA demethylation. TET3 deficiency, or Beck-Fahrner syndrome (BEFAHRS; MIM: 618798), is a recently described neurodevelopmental disorder of the DNA demethylation machinery with a nonspecific phenotype resembling other chromatin-modifying disorders, but inconsistent variant types and inheritance patterns pose diagnostic challenges. Given TET3's direct role in regulating 5-methylcytosine and recent identification of syndrome-specific DNA methylation profiles, we analyzed genome-wide DNA methylation in whole blood of TET3-deficient individuals and identified an episignature that distinguishes affected and unaffected individuals and those with mono-allelic and bi-allelic pathogenic variants. Validation and testing of the episignature correctly categorized known TET3 variants and determined pathogenicity of variants of uncertain significance. Clinical utility was demonstrated when the episignature alone identified an affected individual from over 1000 undiagnosed cases and was confirmed upon distinguishing TET3-deficient individuals from those with 46 other disorders. The TET3-deficient signature - and the signature resulting from activating mutations in DNMT1 which normally opposes TET3 - are characterized by hypermethylation, which for BEFAHRS involves CpG sites that may be biologically relevant. This work expands the role of epi-phenotyping in molecular diagnosis and reveals genome-wide DNA methylation profiling as a quantitative, functional readout for characterization of this new biochemical category of disease.

Delineation of a Human Mendelian Disorder of the DNA Demethylation Machinery: TET3 Deficiency.

Germline pathogenic variants in chromatin-modifying enzymes are a common cause of pediatric developmental disorders. These enzymes catalyze reactions that regulate epigenetic inheritance via histone post-translational modifications and DNA methylation. Cytosine methylation (5-methylcytosine [5mC]) of DNA is the quintessential epigenetic mark, yet no human Mendelian disorder of DNA demethylation has yet been delineated. Here, we describe in detail a Mendelian disorder caused by the disruption of DNA demethylation. TET3 is a methylcytosine dioxygenase that initiates DNA demethylation during early zygote formation, embryogenesis, and neuronal differentiation and is intolerant to haploinsufficiency in mice and humans. We identify and characterize 11 cases of human TET3 deficiency in eight families with the common phenotypic features of intellectual disability and/or global developmental delay; hypotonia; autistic traits; movement disorders; growth abnormalities; and facial dysmorphism. Mono-allelic frameshift and nonsense variants in TET3 occur throughout the coding region. Mono-allelic and bi-allelic missense variants localize to conserved residues; all but one such variant occur within the catalytic domain, and most display hypomorphic function in an assay of catalytic activity. TET3 deficiency and other Mendelian disorders of the epigenetic machinery show substantial phenotypic overlap, including features of intellectual disability and abnormal growth, underscoring shared disease mechanisms.

Dilemma of diagnosing sulphonylurea overdose in children: deliberations and considerations before reaching a diagnosis.

A 15-year-old non-diabetic Caucasian girl presented with sudden onset of seizures, unrecordable blood glucose readings and acute renal failure. She denied any medication ingestion and no other precipitating factors were encountered for this acute presentation. She was treated with intravenous glucose infusion and hydrocortisone injection. Investigations showed a non-ketotic hypoglycaemia with high C-peptide and insulin levels. It took several days and multiple investigations to establish the exact cause of her persistent hypoglycaemia before it was concluded to be secondary to gliclazide overdose in a suicide attempt by the young girl. She made a complete recovery in a week with no apparent lasting neurological or renal impairment.

Inherited duplication of the short arm of chromosome 18p11.32-p11.31 associated with developmental delay/intellectual disability.

Duplications of 18p have been reported in the literature associated with a range of different abnormalities and also in patients with normal phenotypes. The majority of these reports are based solely on G-banded cytogenetic evaluation. The use of arrayCGH characterization has improved the ability to define regions of imbalance and is helping to identify potential underlying triplosufficiency of any duplicated genes. We report on a family where the father and his two daughters all have a duplication 18p11.32-p11.31 characterized by microarray. They present with variable levels of intellectual disability/developmental delay and behavioural difficulties without any physical anomalies. This family contributes toward the growing knowledge of pure duplications of 18p and provides information on interpretation of novel array findings in the context of family history. It also reiterates the importance of elucidating a detailed learning and developmental phenotype and family pedigree in aiding interpretation of genetic testing results.