Mari-Anne Vals

Follow-up study of 2-year-olds born at very low gestational age in Estonia

To study very low gestational age (VLGA, <32 weeks) infants at 2 years of age and to identify the predictors of adverse outcomes.

Coffin–Siris Syndrome with obesity, macrocephaly, hepatomegaly and hyperinsulinism caused by a mutation in the ARID1B gene

Coffin–Siris Syndrome (CSS, MIM 135900) is a rare genetic disorder, and mutations in ARID1B were recently shown to cause CSS. In this study, we report a novel ARID1B mutation identified by whole-exome sequencing in a patient with clinical features of CSS. We identified a novel heterozygous frameshift mutation c.1584delG in exon 2 of ARID1B (NM_020732.3) predicting a premature stop codon p.(Leu528Phefs*65). Sanger sequencing confirmed the c.1584delG mutation as a de novo in the proband and that it was not present either in her parents, half-sister or half-brother. Clinically, the patient presented with extreme obesity, macrocephaly, hepatomegaly, hyperinsulinism and polycystic ovarian syndrome (PCOS), which have previously not been described in CSS patients. We suggest that obesity, macrocephaly, hepatomegaly and/or PCOS may be added to the list of clinical features of ARID1B mutations, but further clinical reports are required to make a definite conclusion.

Familial 1.3-Mb 11p15.5p15.4 Duplication in Three Generations Causing Silver-Russell and Beckwith-Wiedemann Syndromes.

Silver-Russell syndrome (SRS) and Beckwith-Wiedemann syndrome (BWS) are 2 opposite growth-affecting disorders. The common molecular cause for both syndromes is an abnormal regulation of genes in chromosomal region 11p15, where 2 imprinting control regions (ICR) control fetal and postnatal growth. Also, many submicroscopic chromosomal disturbances like duplications in 11p15 have been described among SRS and BWS patients. Duplications involving both ICRs cause SRS or BWS, depending on which parent the aberration is inherited from. We describe to our knowledge the smallest familial pure 1.3-Mb duplication in chromosomal region 11p15.5p15.4 that involves both ICRs and is present in 3 generations causing an SRS or BWS phenotype.

The Frequency of Methylation Abnormalities Among Estonian Patients Selected by Clinical Diagnostic Scoring Systems for Silver–Russell Syndrome and Beckwith–Wiedemann Syndrome

AIMS To study the frequency of methylation abnormalities among Estonian patients selected according to published clinical diagnostic scoring systems for Silver-Russell syndrome (SRS) and Beckwith-Wiedemann syndrome (BWS). MATERIALS AND METHODS Forty-eight patients with clinical suspicion of SRS (n = 20) or BWS (n = 28) were included in the study group, to whom methylation-specific multiplex ligation-dependant probe amplification analysis of 11p15 region was made. In addition, to patients with minimal diagnostic score for either SRS or BWS, multilocus methylation-specific single nucleotide primer extension assay was performed. RESULTS Five (38%) SRS patients with positive clinical scoring had abnormal methylation pattern at chromosome 11p15, whereas in the BWS group, only one patient was diagnosed with imprinting control region 2 (ICR2) hypomethylation (8%). An unexpected hypomethylation of the PLAGL1 (6q24) and IGF2R (6q25) genes in the patient with the highest BWS scoring was found. CONCLUSIONS Compared to BWS, diagnostic criteria used for selecting SRS patients gave us a similar detection rate of 11p15 imprinting disorders as seen in other studies. A more careful selection of patients with possible BWS should be considered to improve the detection of molecularly confirmed cases. Genome-wide multilocus methylation tests could be used in routine clinical practice as it increases the detection rates of imprinting disorders.

Three families with mild PMM2-CDG and normal cognitive development

Congenital disorders of glycosylation (CDG) are caused by defective glycosylation of proteins and lipids. PMM2‐CDG is the most common subtype among the CDG. The severity of PMM2‐CDG is variable. Patients often have a recognizable phenotype with neurological and multisystem symptoms that might cause early death. We report six patients from three families who are diagnosed with a clinically mild PMM2‐CDG and have normal cognitive development. All these patients had delayed gross motor skills with mild‐to‐moderate neurological findings. Cerebellar hypoplasia was detected in all siblings for whom brain MRI was performed. In 5/6 children the Wechsler Intelligence Scale for Children (WISC) showed normal cognitive development with full scale IQ scores ranging from borderline to average. Four patients were diagnosed with PMM2‐CDG at the age of 8 years or later as their neurological symptoms were quite mild and they had been able to participate in regular school programs. We report patients with p.Val231Met/p.Arg239Trp and p.Ile120Thr/p.Gly228Cys genotypes which may cause milder variants of PMM2‐CDG.

Outcome of Children with Marked Changes in Maternal Screening Tests and Normal Karyotype

Objective: To investigate whether chromosomally normal fetuses with marked changes in maternal serum markers and first trimester ultrasound NT marker have an increased risk of congenital anomalies or delayed development at 2 years of age. Methods: Screening tests of 5257 pregnant women were analyzed during a one-year period. Significant changes in biochemical and/or ultrasound markers were documented in 138 pregnant women, whereas positive risk calculation for chromosomal anomalies was evident in 74 of them, who were included in our study. Postnatal study group included 35 children born from mothers with marked changes in screening tests. Results: Among the 74 pregnant women, a structural or genetic abnormality was diagnosed in 16 cases (21.6%), fetal death occurred in 12 cases (16.2%) and child was healthy at the age of 2 years in 31 cases (41.9%). In 3/4 of the cases, a pathology was diagnosed prenatally, while the remaining 1/4 were discovered postnatally. Four children had with congenital anomalies and/or syndromes: two had congenital heart disease – atrial septal defect and ventricular septal defect with patent ductus arteriosus, one Silver-Russell syndrome and one congenital adrenal hyperplasia. It was not possible to get the final information about outcome in 15 cases (20.3%). Conclusions: Children born to these mothers should be actively followed by a pediatrician or clinical geneticist for additional investigations after birth as they have a risk of 5.4% of having a congenital or genetic abnormality.

High incidence of low vitamin B12 levels in Estonian newborns

Vitamin B12 deficiency seems to be more common worldwide than previously thought. However, only a few reports based on data from newborn screening (NBS) programs have drawn attention to that subject. In Estonia, over the past three years, we have diagnosed 14 newborns with congenital acquired vitamin B12 deficiency. Therefore, the incidence of that condition is 33.8/100,000 live births, which is considerably more than previously believed. None of the newborns had any clinical symptoms associated with vitamin B12 deficiency before the treatment, and all biochemical markers normalized after treatment, which strongly supports the presence of treatable congenital deficiency of vitamin B12. During the screening period, we began using actively ratios of some metabolites like propionylcarnitine (C3) to acetylcarnitine (C2) and C3 to palmitoylcarnitine (C16) to improve the identification of newborns with acquired vitamin B12 deficiency. In the light of the results obtained, we will continue to screen the congenital acquired vitamin B12 deficiency among our NBS program. Every child with aberrant C3, C3/C2 and C3/C16 will be thoroughly examined to exclude acquired vitamin B12 deficiency, which can easily be corrected in most cases.

Vermimishäired: kirjanduse ülevaade ja haigusjuhtude kirjeldus

Vermimishairetele on iseloomulikud spetsiifilised, kuid varieeruvad ja kattuvad sumptomid ning Eestis on see toenaoliselt aladiagnoositud haiguste ruhm. Nende haiguste vaga mitmekesise geneetilise etioloogia tottu on diagnoosimiseks vaja kasutada erinevaid molekulaarseid uurimismeetodeid, kaasa arvatud tanapaevaseid kogu genoomi ning metulatsioonitundlikke uuringuid. Tanu uutele uurimismeetoditele on arusaam vermimishairete olemusest ja pohjustest viimaste aastate jooksul oluliselt paranenud, kirjeldatud on ka mitut uut harva esinevat vermitud geenide funktsiooni hairest pohjustatud haigust. Artikli eesmark on anda ulevaade sagedasematest teadaolevatest vermimishairetest, nende sumptomitest, molekulaarsetest pohjustest ning diagnoosimise voimalustest. Eraldi on kirjeldatud kaht vermimishairete haigusjuhtu. Eesti Arst 2017; 96(1):22–35