Biallelic null variants in PNPLA8 cause microcephaly by reducing the number of basal radial glia.

Patatin-like phospholipase domain-containing lipase 8 (PNPLA8), one of the calcium-independent phospholipase A2 enzymes, is involved in various physiological processes through the maintenance of membrane phospholipids. Biallelic variants in PNPLA8 have been associated with a range of paediatric neurodegenerative disorders. However, the phenotypic spectrum, genotype-phenotype correlations and the underlying mechanisms are poorly understood. Here, we newly identified 14 individuals from 12 unrelated families with biallelic ultra-rare variants in PNPLA8 presenting with a wide phenotypic spectrum of clinical features. Analysis of the clinical features of current and previously reported individuals (25 affected individuals across 20 families) showed that PNPLA8-related neurological diseases manifest as a continuum ranging from variable developmental and/or degenerative epileptic-dyskinetic encephalopathy to childhood-onset neurodegeneration. We found that complete loss of PNPLA8 was associated with the more profound end of the spectrum, with congenital microcephaly. Using cerebral organoids generated from human induced pluripotent stem cells, we found that loss of PNPLA8 led to developmental defects by reducing the number of basal radial glial cells and upper-layer neurons. Spatial transcriptomics revealed that loss of PNPLA8 altered the fate specification of apical radial glial cells, as reflected by the enrichment of gene sets related to the cell cycle, basal radial glial cells and neural differentiation. Neural progenitor cells lacking PNPLA8 showed a reduced amount of lysophosphatidic acid, lysophosphatidylethanolamine and phosphatidic acid. The reduced number of basal radial glial cells in patient-derived cerebral organoids was rescued, in part, by the addition of lysophosphatidic acid. Our data suggest that PNPLA8 is crucial to meet phospholipid synthetic needs and to produce abundant basal radial glial cells in human brain development.

Genotype-phenotype correlation in contactin-associated protein-like 2 (CNTNAP-2) developmental disorder.

Contactin-associated protein-like 2 (CNTNAP2) gene encodes for CASPR2, a presynaptic type 1 transmembrane protein, involved in cell-cell adhesion and synaptic interactions. Biallelic CNTNAP2 loss has been associated with "Pitt-Hopkins-like syndrome-1" (MIM#610042), while the pathogenic role of heterozygous variants remains controversial. We report 22 novel patients harboring mono- (n = 2) and bi-allelic (n = 20) CNTNAP2 variants and carried out a literature review to characterize the genotype-phenotype correlation. Patients (M:F 14:8) were aged between 3 and 19 years and affected by global developmental delay (GDD) (n = 21), moderate to profound intellectual disability (n = 17) and epilepsy (n = 21). Seizures mainly started in the first two years of life (median 22.5 months). Antiseizure medications were successful in controlling the seizures in about two-thirds of the patients. Autism spectrum disorder (ASD) and/or other neuropsychiatric comorbidities were present in nine patients (40.9%). Nonspecific midline brain anomalies were noted in most patients while focal signal abnormalities in the temporal lobes were noted in three subjects. Genotype-phenotype correlation was performed by also including 50 previously published patients (15 mono- and 35 bi-allelic variants). Overall, GDD (p < 0.0001), epilepsy (p < 0.0001), hyporeflexia (p = 0.012), ASD (p = 0.009), language impairment (p = 0.020) and severe cognitive impairment (p = 0.031) were significantly associated with the presence of biallelic versus monoallelic variants. We have defined the main features associated with biallelic CNTNAP2 variants, as severe cognitive impairment, epilepsy and behavioral abnormalities. We propose CASPR2-deficiency neurodevelopmental disorder as an exclusively recessive disease while the contribution of heterozygous variants is less likely to follow an autosomal dominant inheritance pattern.

Biallelic mutations in L-dopachrome tautomerase (DCT) cause infantile nystagmus and oculocutaneous albinism.

Infantile nystagmus syndrome (INS) denominates early-onset, involuntary oscillatory eye movements with different etiologies. Nystagmus is also one of the symptoms in oculocutaneus albinism (OCA), a heterogeneous disease mainly caused by defects in melanin synthesis or melanosome biogenesis. Dopachrome tautomerase (DCT, also called TYRP2) together with tyrosinase (TYR) and tyrosin-related protein 1 (TYRP1) is one of the key enzymes in melanin synthesis. Although DCT´s role in pigmentation has been proven in different species, until now only mutations in TYR and TYRP1 have been found in patients with OCA. Detailed ophthalmological and orthoptic investigations identified a consanguineous family with two individuals with isolated infantile nystagmus and one family member with subtle signs of albinism. By whole-exome sequencing and segregation analysis, we identified the missense mutation c.176G > T (p.Gly59Val) in DCT in a homozygous state in all three affected family members. We show that this mutation results in incomplete protein maturation and targeting in vitro compatible with a partial or total loss of function. Subsequent screening of a cohort of patients with OCA (n = 85) and INS (n = 25) revealed two heterozygous truncating mutations, namely c.876C > A (p.Tyr292*) and c.1407G > A (p.Trp469*), in an independent patient with OCA. Taken together, our data suggest that mutations in DCT can cause a phenotypic spectrum ranging from isolated infantile nystagmus to oculocutaneous albinism.

A TUBB6 mutation is associated with autosomal dominant non-progressive congenital facial palsy, bilateral ptosis and velopharyngeal dysfunction.

Congenital cranial dysinnervation disorders (CCDDs) comprise a heterogeneous spectrum of diseases characterized by congenital, non-progressive impairment of eye, eyelid and/or facial movements including Möbius syndrome, Duane retraction syndrome, congenital ptosis, and congenital fibrosis of the extraocular muscles. Over the last 20 years, several CCDDs have been identified as neurodevelopmental disorders that are caused by mutations of genes involved in brain and cranial nerve development, e.g. KIF21A and TUBB3 that each plays a pivotal role for microtubule function. In a five-generation pedigree, we identified a heterozygous mutation of TUBB6, a gene encoding a class V tubulin which has not been linked to a human hereditary disease so far. The missense mutation (p.Phe394Ser) affects an amino acid residue highly conserved in evolution, and co-segregates with a phenotype characterized by congenital non-progressive bilateral facial palsy and congenital velopharyngeal dysfunction presenting with varying degrees of hypomimia, rhinophonia, impaired gag reflex and bilateral ptosis. Expression of the mutated protein in yeast led to an impaired viability compared to wildtype cells when exposed to the microtubule-poison benomyl. Our findings enlarge the spectrum of tubulinopathies and emphasize that mutations of TUBB6 should be considered in patients with congenital non-progressive facial palsy. Further studies are needed to verify whether this phenotype is indeed part of the CCDD spectrum.

Cleft Palate as Distinguishing Feature in a Patient with GABRB3 Epileptic Encephalopathy.

Mutations in GABAA-receptor subunit genes are associated with a heterogeneous spectrum of epilepsies. Patients with epilepsy caused by mutations in a specific GABAA-receptor (GABRA3) occasionally present with orofacial dysmorphism (e.g., cleft palates). While cleft palates have been described in Gabrb3 knockout mice and in humans with GABRB3 variants without epilepsy, the specific combination of epilepsy and cleft palate in humans with GABRB3 mutations has not yet been reported.We describe a patient with epileptic encephalopathy (EE) who presented with therapy-refractory neonatal-onset myoclonic seizures and severe developmental delay. Electroencephalogram showed burst suppression pattern at neonatal age and hypsarrhythmia at infantile age. Initial magnetic resonance imaging was unremarkable. As he additionally presented with a cleft palate, we were curious whether cleft palate and EE had the same genetic origin. Whole exome sequencing of the index patient revealed a novel pathogenic heterozygous de novo mutation in GABRB3 (c.899T > C; p.I300T). In consistency with Gabrb3 knockout mice data, this is the first report of cleft palate in a patient with GABRB3 associated EE.We suggest to add cleft palate to the phenotypic GABRB3 spectrum and to screen for mutations in GABAA-receptors in patients with EE and orofacial dysmorphism.

Dominant SCN2A Mutation Causes Familial Episodic Ataxia and Impairment of Speech Development.

Mutations in SCN2A are associated with a heterogeneous clinical spectrum including epilepsy and autism. Here, we have identified a peculiar phenotype associated with vaccination related exacerbations of ataxia. We report the first family with three individuals affected by SCN2A-associated episodic ataxia (EA) with impaired speech development. The index patient manifested his first episode of subacute cerebellar ataxia at the age of 12 months, 3 weeks after vaccinations for measles, mumps, rubella, and varicella. Cranial magnetic resonance imaging showed a lesion of the left cerebellar hemisphere, which was first considered as a potential cause of the ataxia. The patient fully recovered within 3 weeks, but developed three very similar episodes of transient ataxia within the following 24 months. Whole exome sequencing of the index patient revealed a heterozygous autosomal-dominant mutation in SCN2A (NM_021007, c.4949T > C; p.L1650P), which was confirmed in the likewise affected mother, and was then also identified in the younger brother who developed the first episode of ataxia. We hereby extend the recently described spectrum of SCN2A-associated neurologic disorders, emphasizing that SCN2A mutations should also be considered in familial cases of EA. Coincidental imaging findings or other associated events such as immunizations should not protract genetic investigations.

A heritable microduplication encompassing TBL1XR1 causes a genomic sister-disorder for the 3q26.32 microdeletion syndrome.

Recently, a new syndrome with intellectual disability (ID) and dysmorphic features due to deletions or point mutations within the TBL1XR1 gene located in the chromosomal band 3q26.32 has been described (MRD41, OMIM 616944). One recurrent point mutation in the TBL1XR1 gene has been identified as the cause of Pierpont syndrome (OMIM 602342), a distinct intellectual disability syndrome with plantar lipomatosis. In addition, different de novo point mutations in the TBL1XR1 gene have been found in patients with autism spectrum disorders (ASD) and intellectual disability. Here, we report four patients from two unrelated families in whom array-CGH analysis and real-time quantitative PCR of genomic DNA revealed a TBL1XR1-microduplication. Adjacent genes were not affected. The microduplication occurred as a de novo event in one patient, whereas the other three cases occurred in two generations of a second, unrelated family. We compare and contrast the clinical findings in TBL1XR1 microdeletion, point mutation, and microduplication cases and expand the TBL1XR1-associated phenotypic spectrum. ID, hearing loss, and ASD are common features of TBL1XR1-associated diseases. Our clinical observations add to the increasing evidence of the role of TBL1XR1 in brain development, and they simultaneously demonstrate that different genetic disease mechanisms affecting TBL1XR1 can lead to similar ID phenotypes. The TBL1XR1-microduplication syndrome is an intellectual disability/learning disability syndrome with associated incomplete penetrance ASD, hearing loss, and delay of puberty. Its phenotypic overlap indicates that it is a genomic sister-disorder to the 3q26.32 microdeletion syndrome.

The flexion withdrawal reflex increases in premature infants at 22-26 weeks of gestation due to changes in spinal cord excitability.

AIM: Our aim was to study the development of the cutaneous flexion withdrawal reflex among premature infants admitted to the neonatal intensive care unit of the Children's Hospital, University of Cologne, in 2013. METHODOLOGY: This longitudinal cohort study explored the development of spinal cord excitability of 19 premature infants born at 22-26 weeks of gestation. We performed five investigations per subject and studied changes in the reflex threshold with increasing postnatal age at different behavioural states. The premature infants were stimulated with von Frey filaments on the plantar surface of the foot near the first metatarsophalangeal joint during the first 3 days of life and at postnatal ages of 10-14 days, 21-28 days, 49-59 days and a corrected gestational age of 37-40 weeks. RESULTS: The mean gestational age of the premature infants included in the study was 24 weeks. Premature infants with a gestational age of less than 26 weeks presented a flexion withdrawal reflex with a low threshold (0.5-2.85 milli-Newton) in the first 72 hours of life. CONCLUSION: The flexion withdrawal reflex among premature infants born at less than 26 weeks showed a continuous threshold increase with increasing postnatal age, reflecting changes in spinal cord excitability.

Oligoclonal bands predict multiple sclerosis in children with optic neuritis.

We retrospectively evaluated predictors of conversion to multiple sclerosis (MS) in 357 children with isolated optic neuritis (ON) as a first demyelinating event who had a median follow-up of 4.0 years. Multiple Cox proportional-hazards regressions revealed abnormal cranial magnet resonance imaging (cMRI; hazard ratio [HR] = 5.94, 95% confidence interval [CI] = 3.39-10.39, p < 0.001), presence of cerebrospinal fluid immunoglobulin G oligoclonal bands (OCB; HR = 3.69, 95% CI = 2.32-5.86, p < 0.001), and age (HR = 1.08 per year of age, 95% CI = 1.02-1.13, p = 0.003) as independent predictors of conversion, whereas sex and laterality (unilateral vs bilateral) had no influence. Combined cMRI and OCB positivity indicated a 26.84-fold higher HR for developing MS compared to double negativity (95% CI = 12.26-58.74, p < 0.001). Accordingly, cerebrospinal fluid analysis may supplement cMRI to determine the risk of MS in children with isolated ON.

Inter- and Intrarater Reliability of the Infant Motor Profile in 3- to 18-Month-Old Infants.

PURPOSE: To investigate inter- and intrarater reliability scoring the Infant Motor Profile (IMP). METHODS: A total of 20 infants at risk for motor developmental delay were assessed using the IMP. Six infants were born at term (gestational age: 38-42 weeks), and 14 infants were preterm (gestational age: 24-35 weeks). Videos were analyzed twice with an interval of 1 month by 4 assessors after 2 days of IMP training. RESULTS: Spearman rank scores demonstrated strong interrater and intrarater reliability for total IMP scores (inter: r = 0.80-0.96; intra: r = 0.85-0.97) and the domain of performance (r = 0.95-0.99). Reliability for the domains of variation, variability, and fluency was satisfactory (inter: r = 0.15-0.85; intra: r = 0.30-0.92). The weakest agreement was found in the domain of symmetry (inter: r = 0.20-0.69; intra: r = 0.33-0.65). CONCLUSION: Therapists naive to the IMP demonstrate good intra and interrater reliability (after 2 days of training) for most domains with the exception of symmetry.

Rasmussen encephalitis: incidence and course under randomized therapy with tacrolimus or intravenous immunoglobulins.

PURPOSE: Rasmussen encephalitis (RE) leads to progressive tissue and function loss of one brain hemisphere and often intractable epilepsy. This is the first randomized prospective treatment trial in RE. METHODS: Germany-wide, patients with suspected recent-onset RE were recruited and if eligible randomized to tacrolimus or intravenous immunoglobulins (IVIGs). A loss of motor function or hemispheric volume by ≥ 15% (in patients >12 years at disease onset: ≥ 8%) led to study exit. Untreated patients served as a historical control group. KEY FINDINGS: Over 6.3 years, 21 patients with recent-onset RE were identified. Sixteen were randomized to tacrolimus (n = 9) or IVIG (n = 7). Immunotreated patients had a longer "survival" than the historical controls. Neither treatment was more efficacious than the other. Two tacrolimus patients experienced serious adverse events. No immunotreated but several untreated patients developed intractable epilepsy. No patient with refractory epilepsy became treatment-responsive under immunotherapy. SIGNIFICANCE: The countrywide incidence rate of diagnosed RE is estimated as 2.4 cases/107 people ≤ age 18/year. Treatment with tacrolimus or IVIG may slow down tissue and function loss and prevent development of intractable epilepsy. However, immunotherapy may "arrest" patients in a dilemma state of pharmacoresistant epilepsy but too good function to be offered functional hemispherectomy. These compounds may therefore contribute to the therapeutic armamentarium for RE patients without difficult-to-treat epilepsies.

Universal Newborn Hearing Screening Program: 10-Year Outcome and Follow-Up from a Screening Center in Germany.

Regular reporting of quality control is important in newborn hearing screening, ensuring early diagnosis and intervention. This study reports on a population-based newborn hearing screening program in North-Rhine, Germany and a hospital-based screening at a University Hospital for 2007-2016. The two-staged 'screening' and 'follow-up' program involving TEOAE and AABR recruited newborns through participating birth facilities. Results were sent to the regional tracking center, and the data were analyzed based on recommended benchmarks. The percentage of newborns from the participating birth facilities in the region increased from 1.4% in 2007 to 57.5% in 2016. The 10-year coverage rate for these newborns was 98.7%, the referral rate after a failed two-step screening was 3.4%, and the lost-to-follow-up rate was 1%. At the hospital, >95% of the screened newborns completed screening within 30 days, the 10-year referral rate was 5%, and 64% were referred within 3 months of age. The median time for screening completion was 6 days after birth, for referral it was 74 days after birth, and for diagnosis it was 55 days after birth. Regional-centralized tracking centers with uniform structure are necessary for proper quality control. Obligatory participation of birthing facilities and quality reports may improve performance, but the recommended quality criteria need considerable financial and infrastructural expenditure.

Baclofen intoxication: a "fun drug" causing deep coma and nonconvulsive status epilepticus--a case report and review of the literature.

UNLABELLED: The number of reports on baclofen intoxication has increased in recent years. We report a 15-year-old boy who was referred in a state of deep coma (Glasgow Coma Scale = 3). On clinical examination, he showed sinus bradycardia with normal blood pressure. On admission to the hospital, he presented intermittent short episodes of generalized tonic-clonic seizures. While results of imaging procedures and initial toxicological screening (including standard HPLC analysis and urine test) were negative, a nonconvulsive status epilepticus was diagnosed by electroencephalography (EEG). Identification of baclofen as causative agent was possible after the boy's father reported abusive baclofen intake. Subsequent toxicological target analysis of blood and urine samples confirmed the excessive intake of baclofen and showed a typical elimination pattern with a secondary release. Following 112 h of mechanical ventilation, the boy rapidly regained consciousness and recovered normal neurological behavior. CONCLUSIONS: The present case demonstrates the importance of considering baclofen overdosage in cases of severe coma in combination with an abnormal EEG pattern and sinus bradycardia with normal blood pressure levels, in particular as the substance is popular in internet reports promoting baclofen as a rather harmless "fun drug." Furthermore, it underlines the difficulty to identify baclofen as a causative agent without anamnestic information. Nevertheless, by reviewing existing literature on oral baclofen overdosage, it is possible to picture a nearly specific pattern of clinical symptoms in baclofen intoxication.

A homozygous RAB3GAP2 mutation causes Warburg Micro syndrome.

Warburg Micro syndrome and Martsolf syndrome are clinically overlapping autosomal recessive conditions characterized by congenital cataracts, microphthalmia, postnatal microcephaly, and developmental delay. The neurodevelopmental and ophthalmological phenotype is more severe in Warburg Micro syndrome in which cerebral malformations and severe motor and mental retardation are common. While biallelic loss-of-function mutations in RAB3GAP1 are present in the majority of patients with Warburg Micro syndrome; a hypomorphic homozygous splicing mutation of RAB3GAP2 has been reported in a single family with Martsolf syndrome. Here, we report a novel homozygous RAB3GAP2 small in-frame deletion, c.499_507delTTCTACACT (p.Phe167_Thr169del) that causes Warburg Micro syndrome in a girl from a consanguineous Turkish family presenting with congenital cataracts, microphthalmia, absent visually evoked potentials, microcephaly, polymicrogyria, hypoplasia of the corpus callosum, and severe developmental delay. No RAB3GAP2 mutations were detected in ten additional unrelated patients with RAB3GAP1-negative Warburg Micro syndrome, consistent with further genetic heterogeneity. In conclusion, we provide evidence that RAB3GAP2 mutations are not specific to Martsolf syndrome. Rather, our findings suggest that loss-of-function mutations of RAB3GAP1 as well as functionally severe RAB3GAP2 mutations cause Warburg Micro syndrome while hypomorphic RAB3GAP2 mutations can result in the milder Martsolf phenotype. Thus, a phenotypic severity gradient may exist in the RAB3GAP-associated disease continuum (the "Warburg-Martsolf syndrome") which is presumably determined by the mutant gene and the nature of the mutation.

Horizontal gaze palsy with progressive scoliosis: three novel ROBO3 mutations and descriptions of the phenotypes of four patients.

PURPOSE: Clinical and molecular characterization of patients with horizontal gaze palsy with progressive scoliosis (HGPPS) to extend existing knowledge of the phenotype caused by mutations in the Roundabout homolog of Drosophila 3 (ROBO3) gene. METHODS: Four patients (aged 6 months to 13 years), two of them siblings, with features of horizontal gaze palsy and their parents were examined clinically and by molecular testing of the ROBO3 gene. The three families were unrelated, but parents in each family were consanguineous. RESULTS: We identified three novel homozygous ROBO3 mutations in four patients with typical ophthalmologic signs of HGPPS. We found an exonic insertion/deletion mutation (c.913delAinsTGC; p.Ile305CysfsX13), a 31 bp deletion including the donor splice site of exon 17 and adjacent exonic and intronic sequences (c.2769_2779del11, 2779+1_+20del20), and a missense mutation located next to a splice donor site (c.3319A>C) resulting in skipping of exon 22, as shown by cDNA analysis. CONCLUSIONS: We describe three novel mutations in the ROBO3 gene and the detailed clinical phenotype of HGPPS. One patient displayed marked convergence upon attempting smooth pursuits to both sides. In one patient, the typical ophthalmologic phenotype, the neuroradiologic findings, and molecular testing led to the diagnosis even before scoliosis developed. In addition to the typical magnetic resonance imaging brain signs of HGPPS, this patient had marked hypoplasia of the frontal lobes and corpus callosum. In summary, diagnosis of HGPPS may be established by ophthalmologic and molecular investigation early in life, allowing ongoing orthopedic surveillance from an early stage.

PNPT1 mutations may cause Aicardi-Goutières-Syndrome.

BACKGROUND: Aicardi-Goutières syndrome (AGS) is a clinically and genetically heterogenous autoinflammatory disorder caused by constitutive activation of the type I interferon axis. It has been associated with the genes TREX1, RNASEH2A, RNASEH2B, RNASEH2C, SAMHD1, ADAR1, IFIH1. The clinical diagnosis of AGS is usually made in the context of early-onset encephalopathy in combination with basal ganglia calcification or white matter abnormalities on cranial MRI and laboratory prove of interferon I activation. CASE PRESENTATION: We report a patient with early-onset encephalopathy, severe neurodevelopmental regression, progressive secondary microcephaly, epilepsy, movement disorder, and white matter hyperintensities on T2 weighted MRI images. Via whole-exome sequencing, we identified a novel homozygous missense variant (c.1399C > T, p.Pro467Ser) in PNPT1 (NM_033109). Longitudinal assessment of the interferon signature showed a massively elevated interferon score and chronic type I interferon-mediated autoinflammation. CONCLUSION: Bi-allelic mutations in PNPT1 have been reported in early-onset encephalopathy. Insufficient nuclear RNA import into mitochondria with consecutive disruption of the respiratory chain was proposed as the main underlying pathomechanism. Recent studies have shown that PNPT1 deficiency causes an accumulation of double-stranded mtRNAs in the cytoplasm, leading to aberrant type I interferon activation, however, longitudinal assessment has been lacking. Here, we present a case of AGS with continuously elevated type I interferon signature with a novel likely-pathogenic homozygous PNTP1 variant. We highlight the clinical value of assessing the interferon signature in children with encephalopathy of unknown origin and suggest all patients presenting with a phenotype of AGS should be screened for mutations in PNPT1.

High and low birth weight and its implication for growth and bone development in childhood and adolescence.

AIM: To investigate the relationship of birth weight (BW) to anthropometric measures, local body composition and bone development. POPULATION AND METHODS: 284 individuals (age 5-19 yr, 145 females) were recruited from the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study. Parameters of bone development (cortical bone mineral density [BMDcort], endosteal circumference [CE]) and of local body composition (cross-sectional fat area [FA]) were analyzed by pQCT at the forearm. Parameters were transformed into SD scores to adjust for age or height. RESULTS: BW predicted weight-SDS (R = 0.221), height-SDS (R = 0.260) and FA-SDS (R = 0.150). Individuals with lower BW (< 10th percentile) had lower weight-SDS (p < 0.01), height-SDS (p < 0.01), BMDcort-SDS (p = 0.02) and higher CE-SDS (p = 0.05). BMDcort was correlated with BW (r = -0.319) and FA (r = -0.283) in pubertal females. CONCLUSION: BW is characterized by direct and indirect effects on growth, body composition and bone development.

Novel mutations in SLC6A5 with benign course in hyperekplexia.

Infants suffering from life-threatening apnea, stridor, cyanosis, and increased muscle tone may often be misdiagnosed with infantile seizures and inappropriately treated because of lack and delay in genetic diagnosis. Here, we report a patient with increased muscle tone after birth and hypertonic attacks with life-threatening apnea but no epileptiform patterns in EEG recordings. We identified novel compound heterozygous variants in SLC6A5 (NM_004211.4:c.[1429T > C];[1430delC]) by trio whole-exome sequencing, containing a base deletion inherited by the asymptomatic mother leading to a frameshift (c.1430delC, p.Ser477PhefsTer9) and a de novo base exchange leading to an amino acid change (c.1429T > C, p.Ser477Pro). To date, there are four known disease-associated genes for primary hyperekplexia, all of which are involved in the functioning of glycinergic synapses. SLC6A5 encodes the sodium- and chloride-dependent glycine transporter 2 (GlyT2), which recaptures glycine, a major inhibitory transmitter in the brainstem and spinal cord. The diagnosis altered the patient's medical care to his benefit because SLC6A5 mutations with rather benign courses of hyperekplexia may be spared of needless pharmacotherapy. Symptoms eventually decreased in frequency until about once in 2 mo at 2 yr age. We present the first report of halting hyperekplexia episodes by maternal soothing in multiple instances. We highlight the importance of clarifying the genetic diagnosis by rapid next-generation sequencing techniques in this group of infantile apneic attacks with hyperekplexia due to the broad differential diagnoses.

Mendeliome sequencing enables differential diagnosis and treatment of neonatal lactic acidosis.

BACKGROUND: Neonatal lactic acidosis can be associated to severe inborn errors of metabolism. Rapid identification of the underlying disorder may improve the clinical management through reliable counseling of the parents and adaptation of the treatment. METHODS: We present the case of a term newborn with persistent hypoglycemia on postnatal day 1, who developed severe lactic acidosis, aggravating under intravenous glucose administration. Routine metabolic investigations revealed elevated pyruvate and lactate levels in urine, and magnetic resonance spectroscopy showed a lactic acid peak and decreased N-acetylaspartate levels. Mitochondrial disorders, e.g., pyruvate dehydrogenase (PDH) deficiency, were the major differential diagnoses. However, both hypoglycemia and the elevated lactate to pyruvate ratio in serum (=55.2) were not typical for PDH deficiency. We used "Mendeliome sequencing", a next-generation sequencing approach targeting all genes which have been previously linked to single-gene disorders, to obtain the correct diagnosis. RESULTS: On day 27 of life, we identified a homozygous stop mutation in the PDHX gene, causing pyruvate dehydrogenase E3-binding protein deficiency. After starting the ketogenic diet, the infant recovered and is showing delayed but progressive development. CONCLUSIONS: Mendeliome sequencing was successfully used to disentangle the underlying cause of severe neonatal lactic acidosis. Indeed, it is one of several targeted sequencing approaches that allow rapid and reliable counseling of the parents, adaptation of the clinical management, and renunciation of unnecessary, potentially invasive and often costly diagnostic measures.

Therapy of the neonatal abstinence syndrome with tincture of opium or morphine drops.

BACKGROUND: Treating opioid-addicted women with methadone in pregnancy increased the number of newborns suffering from neonatal abstinence syndrome (NAS). High-pitch crying, insomnia, tremor, myoclonic jerks, vomiting, diarrhoea and poor weight gain were reported symptoms, which were evaluated using the Finnegan (F)-score. Earlier phenobarbital or paregoric had been used to suppress symptoms. We surveyed the administration of pure mu-agonist morphine (MO) in comparison to the alcoholic opioid mixture in tincture of opium (TO). Thirty-three newborns were included in the survey, after informed consent by their parents. RESULTS: NAS started 3-5 days after delivery and lasted for 27 or 30 days (mean) in the TO and MO groups, respectively. In either of the tested parameters, we found no significant differences between the two groups (2P < 0.05). The maximum F-score was similar in both groups, but the dose to suppress NAS was higher in the MO group (0.6-0.5 mg/day; total dose 61.6-42.7 mg of morphine). The duration of the therapy was longer in the MO than in the TO group (37.5-32.4 days). On the other hand the weight gain was better in the MO group than in the TO group (25-19 g/day), but was reduced in both groups compared with healthy newborns. CONCLUSIONS: Morphine is suitable to treat NAS in a similar manner as tincture of opium, but avoids unwanted effects of the alcoholic extracts with various alkaloids in the tincture of opium and allows better weight gain of the newborns.