The First Registered Type 0 Spinal Muscular Atrophy Patient in Latvia: Call for Change in Prenatal Diagnostic Procedures.

This case report presents the first registered patient in Latvia with type 0 spinal muscular atrophy (SMA). During the first-trimester ultrasonography of the unborn patient, an increased thickness of the nuchal fold was detected. The mother reported decreased foetal movements during the pregnancy. After the boy was born, his general condition was extremely severe. The clinical signs indicated a suspected neuromuscular disorder. A precise diagnosis, type 0 SMA, was determined 7 days after birth through a newborn pilot-screening for SMA, which was conducted for all newborns whose parents consented to participate. The condition of the infant deteriorated. He had severe respiratory distress followed by multiple events leading to his death. Currently, there are only a few published case reports detailing an increased nuchal translucency (NT) measurement in association with a diagnosis of SMA in the foetus. However, an increased NT measurement is a clinically relevant sign as it can be related to genetic syndromes, foetal malformations, disruptions, and dysplasias. Since there is no cure for infants with type 0 SMA at present, it is crucial to be able to detect this disease prenatally in order to provide the best possible care for the patient and parents. This includes the provision of palliative care for the patient, among other measures. This case report highlights the prenatal signs and symptoms in relation to type 0 SMA.

Overview of Neuromuscular Disorder Molecular Diagnostic Experience for the Population of Latvia.

Background and Objectives: Genetic testing has become an integral part of health care, allowing the confirmation of thousands of hereditary diseases, including neuromuscular disorders (NMDs). The reported average prevalence of individual inherited NMDs is 3.7-4.99 per 10,000. This number varies greatly in the selected populations after applying population-wide studies. The aim of this study was to evaluate the effect of genetic analysis as the first-tier test in patients with NMD and to calculate the disease prevalence and allelic frequencies for reoccurring genetic variants. Methods: Patients with NMD from Latvia with molecular tests confirming their diagnosis in 2008-2020 were included in this retrospective study. Results: Diagnosis was confirmed in 153 unique cases of all persons tested. Next-generation sequencing resulted in a detection rate of 37%. Two of the most common childhood-onset NMDs in our population were spinal muscular atrophy and dystrophinopathies, with a birth prevalence of 1.01 per 10,000 newborns and 2.08 per 10,000 (male newborn population), respectively. The calculated point prevalence was 0.079 per 10,000 for facioscapulohumeral muscular dystrophy type 1, 0.078 per 10,000 for limb-girdle muscular dystrophy, 0.073 per 10,000 for nondystrophic congenital myotonia, 0.052 per 10,000 for spinobulbar muscular atrophy, and 0.047 per 10,000 for type 1 myotonic dystrophy. Discussion: DNA diagnostics is a successful approach. The carrier frequencies of the common CAPN3, FKRP, SPG11, and HINT1 gene variants as well as that of the SMN1 gene exon 7 deletion in the population of Latvia are comparable with data from Europe. The carrier frequency of the CLCN1 gene variant c.2680C>T p.(Arg894Ter) is 2.11%, and consequently, congenital myotonia is the most frequent NMD in our population.

Implication of Genetic Testing and Pregnancy Outcome in a Woman with Unbalanced Translocation t(1;6).

BACKGROUND Parental chromosomal structural abnormalities can lead to diverse chromosomal imbalances at meiotic segregation during gametogenesis and subsequent early pregnancy loss or birth of a child with a chromosomal abnormality. The incidence of unbalanced translocations is 1 per 1000 newborns versus 3 per 1000 newborns for balanced rearrangements. Here, we present the case of a mother with an unbalanced chromosomal translocation and her offspring. CASE REPORT Our patient had a 1p36.31 duplication of 0.22 Mb and 6qter deletion of 1.2 Mb. She had 5 pregnancies with different outcomes. Her first child died 24 h after birth due to a congenital heart defect. Her second pregnancy resulted in the birth of a girl who was postnatally diagnosed with 1p36 deletion syndrome. The third and fourth pregnancies ended spontaneously in the first trimester. For her last pregnancy, the patient underwent a diagnostic amniocentesis at the 16th week of gestation. A large 5.4-Mb pathogenic duplication of 1p36.33 was detected in the fetus and the woman decided to terminate the pregnancy. CONCLUSIONS In this case report, we detail the different pregnancy outcomes induced by the mother's unbalanced chromosomal translocation and review the prenatal diagnostic genetic testing. Our report clearly demonstrates the complementary nature of chromosomal microarrays and conventional karyotyping.

Two Cases of Leigh Syndrome in One Family: Diagnostic Challenges and Clinical Management Experience in Latvia.

Leigh syndrome is a neurodegenerative disorder with an incidence of 1 : 40,000 live births. The clinical presentation of LS is highly variable with heterogeneity in the disease-associated symptoms of cerebellar, motor, and extrapyramidal dysfunction and common infections. There is no effective treatment for this condition; as such, the prognosis of this condition is very poor with death occurring within the first few years of life. In this study, we report the first LS case in Latvia with SURF1 pathogenic variants in two siblings. The difficulties encountered establishing a diagnosis for the first proband and the effective prenatal diagnosis for the second offspring that led to termination of the pregnancy are discussed.

Regulatory landscape of providing information on newborn screening to parents across Europe.

Newborn screening (NBS) is an important part of public healthcare systems in many countries. The provision of information to parents about NBS is now recognised as an integral part of the screening process. Informing parents on all aspects of screening helps to achieve the benefits, promote trust and foster support for NBS. Therefore, policies and guidelines should exist to govern how the information about NBS is provided to parents, taking into account evidence-based best practices. The purpose of our survey was to explore whether any legally binding provisions, guidelines or recommendations existed pertaining to the provision of information about NBS to parents across Europe. Questions were designed to determine the regulatory process of when, by whom and how parents should be informed about screening. Twenty-seven countries participated in the survey. The results indicated that most countries had some sort of legal framework or guidelines for the provision of information to parents. However, only 37% indicated that the provision of information was required prenatally. The majority of countries were verbally informing parents with the aid of written materials postnatally, just prior to sample collection. Information was provided by a neonatologist, midwife or nurse. A website dedicated to NBS was available for 67% of countries and 89% had written materials about NBS for parents. The survey showed that there is a lack of harmonisation among European countries in the provision of information about NBS and emphasised the need for more comprehensive guidelines at the European level.

The Fetal Phenotype of Noonan Syndrome Caused by Severe, Cancer-Related PTPN11 Variants.

BACKGROUND The nuchal translucency measurement is the major focus of an early fetal ultrasound scan, with the goal to identify various inherited conditions, such as chromosomal aberrations and others. The diagnostic strategy for fetuses with increased nuchal translucency and normal karyotype is not clearly defined and may vary between countries. CASE REPORT We describe 2 cases of Noonan syndrome diagnosed prenatally by ultrasound scanning and genetic testing. The prenatal ultrasound scans showed abnormal nuchal translucencies, cystic lymphangioma/cystic hygroma, and other findings. Both fetuses had normal karyotype; however, after additional analysis, pathogenic variants of the PTPN11 gene (encoding SH2 domain-containing protein tyrosine phosphatase) were found, previously frequently described as somatic variants in hematological malignancies in postnatal life, but not previously described with severe prenatal phenotype of Noonan syndrome. CONCLUSIONS Our case reports confirm the hypothesis that severe, cancer related PTPN11 variants cause severe Noonan syndrome prenatal phenotype, when inherited in the germline.Analysis of pathogenic variants associated with Noonan syndrome should be included in the prenatal diagnostics for fetuses with increased nuchal translucency and normal karyotype.