Diagnosis of cystic fibrosis: a high heterogeneity of symptoms and genotypes in a Brazil population.

INTRODUCTION: In highly multiracial populations with inadequate newborn screening, knowledge of the various phenotypic presentations of Cystic Fibrosis (CF) can help reach an early diagnosis. This study aims to describe phenotypes and genotypes at the time of CF diagnosis in a state in the Northeast Region of Brazil. METHODS: Retrospective cross-sectional study. Clinical data were extracted from the medical records of CF patients. Clinical, laboratory, and genotypic characteristics were described for patients admitted to a tertiary referral center between 2007 and 2021. RESULTS: Fifty-eight (58) patients were included in the study, 53.5% of whom were diagnosed through clinical suspicion. The median age at diagnosis was 4.7 months (IQR: 1.5-14.8 months). Five patients had false-negative results in the newborn screening. Faltering growth was the most frequent clinical manifestation. Bronchiectasis and a history of pneumonia predominated in those older than ten, while thinness, underweight, and electrolyte imbalances were more frequent in children under two. Sequencing of the CFTR gene identified 27 genotypes, with at least one class I-III variant in all patients, and nine variants that are rare, previously undescribed, or have uncertain significance (619delA, T12991, K162Q, 3195del6, 1678del > T, 124del123bp, 3121-3113 A > T). The most frequent alleles were p.Phe508del, p.Gly542*, p.Arg334Trp, and p.Ser549Arg. CONCLUSIONS: Malnutrition and electrolyte imbalances were the most frequent phenotypes for children < 2 years and were associated with genotypes including 2 class I-III variants. Rare and previously undescribed variants were identified. The p.Gly542*, p.Arg334Trp, and p.Ser549Arg alleles were among the most frequent variants in this population.

Microdeletion 1p32p31 Presenting with Moyamoya Disease and Incomplete Hippocampal Inversion.

Background: The chromosome 1p32p31 deletion syndrome is a contiguous gene disorder with a variable phenotype characterized by brain malformations with or without urinary tract defects, besides neurodevelopmental delay and dysmorphisms. An expanded phenotype was proposed based on additional findings, including one previous report of a patient presenting with moyamoya disease. Case Presentation: The authors report a patient presenting with early neurodevelopmental delay, hydrocephalus, renal malformation, and dysmorphisms. After presenting with a sudden choreic movement disorder, the neuroimaging investigation revealed an ischemic stroke, moyamoya disease, and bilateral incomplete hippocampal inversion. Chromosomal microarray analysis revealed a deletion of 13.2 Mb at 1p31.3p32.2, compatible with the contiguous gene syndrome caused by microdeletions of this region. Discussion/Conclusion: This is the second report of a patient who developed Moyamoya disease and the first to describe bilateral incomplete hippocampal inversion in this microdeletion syndrome.

Expanding the phenotypic spectrum of CLCN2-related leucoencephalopathy and ataxia.

Mutations in CLCN2 are a rare cause of autosomal recessive leucoencephalopathy with ataxia and specific imaging abnormalities. Very few cases have been reported to date. Here, we describe the clinical and imaging phenotype of 12 additional CLCN2 patients and expand the known phenotypic spectrum of this disorder. Informed consent was obtained for all patients. Patients underwent either whole-exome sequencing or focused/panel-based sequencing to identify variants. Twelve patients with biallelic CLCN2 variants are described. This includes three novel likely pathogenic missense variants. All patients demonstrated typical MRI changes, including hyperintensity on T2-weighted images in the posterior limbs of the internal capsules, midbrain cerebral peduncles, middle cerebellar peduncles and cerebral white matter. Clinical features included a variable combination of ataxia, headache, spasticity, seizures and other symptoms with a broad range of age of onset. This report is now the largest case series of patients with CLCN2-related leucoencephalopathy and reinforces the finding that, although the imaging appearance is uniform, the phenotypic expression of this disorder is highly heterogeneous. Our findings expand the phenotypic spectrum of CLCN2-related leucoencephalopathy by adding prominent seizures, severe spastic paraplegia and developmental delay.

A genetic study of a Brazilian cohort of patients with X-linked hypophosphatemia reveals no correlation between genotype and phenotype.

Aim: X-linked hypophosphatemia (XLH) is the most common inherited form of rickets, and it is caused by pathogenic inactivating variants of the phosphate-regulating endopeptidase homolog X-linked (PHEX) gene. The main purpose of this study is to identify the presence of a genotype-phenotype correlation in a cohort of XLH patients. Methods: This is a retrospective study including patients diagnosed with hypophosphatemic rickets, confirmed by clinical, radiological, and laboratory findings. Medical records were reviewed for phenotypic analyses. Genomic DNA was extracted from the peripheral blood lymphocytes, and PHEX sequencing was performed by exomic NGS sequencing. The Wilcoxon rank-sum test and the two-tailed Fisher's exact test were employed for the statistical analyses of this study. Results: A total of 41 patients were included in this study, and 63.41% (26/41) of the patients were female. The mutation analyses identified 29.27% missense variants and 29.72% nonsense variants, most of them were considered deleterious (66.41%). Six novel deleterious variants in the PHEX gene were detected in seven patients. The median concentrations of pretreatment serum calcium, phosphorus, and parathyroid hormone (PTH) were not significantly different among patients with different genotypes. An orthopedic surgery due to bone deformity was required in 57.69%. Conclusions: Our analysis did not identify any specific genotype as a predictor. No significant genotype-phenotype correlation was found, suggesting that the recognition of subjacent pathogenic mutation in the PHEX gene may have limited prognostic value. Despite this finding, genetic testing may be useful for identifying affected individuals early and providing appropriate treatment.

Distal deletion at 22q11.2 as differential diagnosis in Craniofacial Microsomia: Case report and literature review.

Craniofacial Microsomia (CFM) also known as Oculo-auriculo-vertebral Spectrum (OAVS) or Goldenhar Syndrome, presents wide phenotypic and etiological heterogeneity. It affects mainly the structures originated from the first and second pharyngeal arches. In addition, other major anomalies may also be found, including congenital heart diseases. In this study, we report a patient with distal deletion in the 22q11.2 region and a phenotype which resembles CFM. The proband is a girl, who presented bilateral preauricular tags, left auditory canal stenosis, malar hypoplasia, cleft lip and palate, mild asymmetry of soft tissue in face, congenital heart disease, intestinal atresia, annular pancreas and hydronephrosis. The genomic imbalances investigation by Multiplex Ligation-dependent Probe Amplification (MLPA) and Chromosomal Microarray Analysis (CMA) revealed a distal deletion of 1,048 kb at 22q11.2 encompassing the region from Low Copy Repeats (LCRs) D to E. We did review of the literature and genotype-phenotype correlation. This is the sixth case of distal 22q11.2 deletion resembling CFM and the second encompassing the region between LCRs D to E. All cases share some phenotypic signs, such as preauricular tags, facial asymmetry, cleft lip and palate, and congenital heart diseases. Candidate genes in this region have been studied by having an important role in pharyngeal arches developmental and in congenital heart diseases, such as HIC2, YPEL1and MAPK1/ERK2. This case corroborates the phenotypic similarity between 22q11.2 distal deletion and CFM/OAVS. It also contributes to genotype-phenotype correlation and reinforces that candidate genes for CFM, in the 22q11.2 region, might be located between LCRs D and E.