Spectrum of genetic variants in 306 patients with non-syndromic hearing loss from Croatia.

AIM: To determine the spectrum and frequency of disease-causing variants in patients with non-syndromic hearing loss (NSHL) and to investigate the diagnostic yield of the applied genetic methods. METHODS: The study enrolled 306 unrelated patients with childhood-onset, mild-to-profound NSHL referred to Children's Hospital Zagreb for genetic testing between March 2006 and October 2023. The GJB2 variants were analyzed with the multiplex ligation-dependent probe amplification method and Sanger sequencing of the coding region of the GJB2 gene. In 21 patients negative for GJB2 biallelic variants, clinical exome sequencing (CES) was performed. RESULTS: Among 234 disease-associated GJB2 alleles detected, 19 were clinically relevant, of which 18 were reported as pathogenic/likely pathogenic. The c.35delG variant accounted for 73.5% of the mutated alleles. More than half of the patients with biallelic GJB2 variants (64/110, 58.2%) were 35delG homozygotes. Seventeen non-GJB2 variants were found in 10 genes (TECTA, NOG, SLC26A4, PCDH15, TMPRSS3, USH2A, GATA3, MYO15A, SOX10, COL2A1) in 11 participants, and 5 variants (in TECTA, NOG, PCDH15, and SOX10) were novel (29.4%). CONCLUSION: We were able to elucidate the genetic cause of hearing loss in 121 patients, with an overall diagnostic rate of 39.5%. The c.35delG was the most common variant. CES allowed us to diagnose almost half of the patients with HL; to distinguish NSHL from the syndromic form of HL in cases where the phenotype was unclear or where symptoms were absent from an early age; and to discover novel variants.

Neurodevelopmental disorder caused by an inherited novel KMT5B variant: case report.

Neurodevelopmental disorders are a large group of disorders that affect ~ 3% of children and represent a serious health problem worldwide. Their etiology is multifactorial and includes genetic, epigenetic, and environmental causes. Mounting evidence shows the importance of genetic causes, especially genes involved in the central nervous system development. As recently discovered, the KMT5B gene is related to abnormal activities of the enzymes that regulate histone activity and gene expression during brain development. Pathogenic KMT5B gene variants lead to autosomal dominant, intellectual developmental disorder 51 (OMIM # 617788). Also, reports on patients with additional features suggest that the KMT5B gene alterations lead to multisystem involvement. Here, we report on a male patient with a severe neurodevelopmental disorder caused by a novel KMT5B gene variant inherited from his mother. The patient had severe intellectual disability, absent speech, marked autistic behavior, attention deficit hyperactivity disorder, and different clinical features, including thoracic scoliosis, dysmorphic facial features, and tall stature. In contrast, his mother, with the same KMT5B variant, had mild intellectual disability and some autistic traits (stereotype hand movement). We elucidated pathogenetic mechanisms that could influence phenotype characteristics. Our findings emphasize the importance of a comprehensive clinical and molecular approach to these patients in order to provide optimal health care.

The first case report of distal 16p12.1p11.2 trisomy and proximal 16p11.2 tetrasomy inherited from both parents.

Recurrent copy number variants in the chromosomal region 16p11.2 are among the most frequent genetic causes of neurodevelopmental disorders. The increasing prevalence of brain structural anomalies is also associated with 16p11.2 deletions and duplications. We report on a four-year-old boy with microcephaly, trigonocephaly, and dysmorphic features. The patient also exhibited motor delay and autism spectrum disorder. Microarray analysis showed a single-copy gain of a 1.187 kb segment in the 16p12.1p11.2 region and a two-copy gain of a 525 kb segment in the 16p11.2 region. Parental analysis revealed a 1.7 Mb duplication at the 16p12.1p11.2 (BP1-BP5 region) in the father and a 525 kb duplication in the 16p11.2 region (BP4-BP5) in the mother. The patient inherited the entire abnormality from each parent and, as a result, presented with partial trisomy of the 16p12.1p11.2 region and partial tetrasomy of the 16p11.2 region. The MLPA P343 Autism-1 Probemix was used to verify the copy number gains in the 16p11.2 region detected by chromosomal microarray analysis. Double duplications are very rare chromosomal rearrangements. The phenotype for distal 16p12.1p11.2 trisomy (BP1-BP3) and proximal 16p11.2 (BP4-BP5) tetrasomy is unknown. To our knowledge, this is the first patient described in the literature who inherited 16p11.2 duplications from both parents.

Inherited Thrombophilia Associated With Ischemic Pediatric Stroke in Parent-Child Pairs.

BACKGROUND: We aimed to examine inherited thrombophilia frequencies by extending genetic profile to previously rarely or not investigated polymorphisms in children with ischemic pediatric stroke (IPS) and their parents. METHODS: The study included 33 children: 23 with perinatal arterial ischemic stroke (PAIS), eight with childhood arterial ischemic stroke (CAIS), and two with sinovenous thrombosis and their parents (33 mother-child, 12 father-child, and 12 mother-father-child pairs). Genotyping of FV-Leiden, FV-H1299R, FII-G20210A, ß-fibrinogen-455G>A, FXIII-A-Val34Leu, PAI-1(4G/5G), HPA-1, MTHFR-C677T, MTHFR-A1298C, ACE(I/D), and APOE(ε2-4) was performed using CVD Strip assay (ViennaLab, Austria). RESULTS: At least one and up to seven simultaneously present polymorphisms were observed in all children with IPS, mothers, and fathers. More than five simultaneously present polymorphisms were identified threefold more frequently in children with IPS (10 of 33; 30%) compared with the child control group (17 of 150; 11%), yielding a statistically significant difference between the two groups (odds ratio [OR] = 3.40; 95% confidence interval [CI] = 1.39 to 8.35; P = 0.012). Stronger association was revealed for PAIS (OR = 4.17; 95% CI = 1.55 to 11.29; P = 0.008) and CAIS subgroups (OR = 7.82; 95% CI = 1.79 to 34.20; P = 0.012). Complete match of polymorphisms was not identified in any parent-child pair. A partial match (one to four mutual polymorphisms) was found in 11 of 12 parent-child pairs where until three mutual polymorphisms was present in 11 of 12 (91.7%) father-child compared with 21 of 33 (63.6%) mother-child pairs. CONCLUSIONS: According to obtained results the simultaneous presence of more than five polymorphisms is associated with a higher risk for IPS occurrence, suggesting the risk enhancement for PAIS in the presence of pregnancy complications or for CAIS in conjunction with maternal comorbidity and positive family history. The presence of up to three mutual polymorphisms more frequently in father-child than mother-child pairs suggests significant paternal contribution of inherited thrombophilia to increased risk of IPS.

Visual impairment in children with cerebral palsy: Croatian population-based study for birth years 2003-2008.

AIM: To evaluate visual impairment (VI) in children with cerebral palsy (CP). METHODS: This population-based study included 419 children from the Surveillance of Cerebral Palsy in Europe (SCPE) C28 RCP-HR - Register of Cerebral Palsy of Croatia born 2003-2008. Vision in children with CP (according to SCPE) was classified as normal or impaired, with the subcategory of severe VI. The proportion of children with VI was assessed in groups with different CP type/subtype, gross and fine motor function, and gestational age (GA). RESULTS: A total of 266 children had some degree of VI (266/400; 66.5%), 134 had normal vision, and data on VI were unknown for 19 children. Severe VI was present in 44 children (44/400; 11%). The proportion of children with VI and severe VI increased with the Gross Motor Function Classification System and Bimanual Fine Motor Function levels. Children with bilateral spastic CP had the highest frequency of severe VI (14.9%). The percentage of severe VI in children with bilateral spastic CP was 53.8% in the group born <28 weeks of GA, 13.3% in the group born 28-31 weeks of GA, 11.1% in the group born 32-36 weeks of GA, and 24.4% in the group born >36 weeks of GA (λ2=4.95; df=6; P<0.001). CONCLUSION: Children with CP have a high prevalence of VI and severe VI, which is increasing with the level of motor impairment. Severe VI is significantly more common in children with bilateral spastic CP, especially among extremely premature infants.

The characteristics of transcranial color-coded duplex sonography in children with cerebral arteriovenous malformation presenting with headache.

PURPOSE: Cerebral arteriovenous malformations (AVM) are uncommon lesions. They are most often presented in childhood as intracranial hemorrhage. The aim of this report is to present the use of transcranial color-coded duplex sonography (TCCS) in detection of AVMs in children suffering headache. METHODS: This report describes five pediatric patients with headache and cerebral AVM which were initially discovered by TCCS. Diagnosis was confirmed by magnetic resonance imaging and digital subtraction angiography. RESULTS: In all patients, TCCS showed saccular enlargement of the vessels with a multicolored pattern corresponding to the different directions of blood flow. Spectral analysis showed significantly high flow systolic and diastolic velocities and low resistance index. CONCLUSIONS: In this report, we describe TCCS as a valuable non-invasive, harmless, low-cost, widely available method for the detection and follow-up of hemodynamic changes of AVMs in children with headache, before and after treatment.

[INFANTILE COLIC - NEWER APPROACH TO AN OLD PROBLEM]. / DOJENACKE KOLIKE - NOVIJI PRISTUP STAROM PROBLEMU.

Infantile colic have been known for the long time and are one of the most common reasons for pediatrician's appointment in early infancy. However, their etiology and pathogenesis are yet to be determined. Diagnosis is based on thorough medical history and physical examination. Special attention should be given to red flags or warning signs which could indicate a presence of serious illness. If no other abnormality is present, except inconsolable crying, there is no need for further diagnostic procedures. There is an extensive range of proposed therapeutic measures; however scientific evidence for all of them is scarce. Therefore, the aim of this review article is to present currently available evidence for the management of infantile colic and to provide a possible therapeutic algorithm.