Novel CTR9 germline pathogenic splice site variant in siblings with Wilms tumor from Tanzania.

Wilms tumor is the most common childhood renal malignancy. Though mostly non-genetic, it can be syndromic with the involvement of many Wilms tumor predisposing genes and non-syndromic with the involvement of four genes: WT1, REST, TRIM28, and CTR9. Familial and bilateral Wilms tumors do occur, but these are rare. So far, four Wilms tumor families with pathogenic variants in the CTR9 gene have been described, all (presumably) inherited from unaffected fathers, and three leading to deletion of exon 9. We are reporting female siblings, of whom one has a bilateral Wilms tumor, with a novel pathogenic splice site variant in the CTR9 gene, leading to deletion of exon 9, and inherited from their asymptomatic father. The loss of heterozygosity in the tumor was confirmed. In conclusion, CTR9 pathogenic variants are a very rare cause of Wilms tumors and typically result in familial Wilms tumors.

Novel likely pathogenic variant in NR5A1 gene in a Tanzanian child with 46,XY differences of sex development, inherited from the mosaic father.

Summary: Pathogenic variants in the nuclear receptor subfamily 5 group A member 1 gene (NR5A1), which encodes steroidogenic factor 1 (SF1), result in 46,XY and 46,XX differences of sex development (DSD). In 46,XY individuals with a pathogenic variant in the NR5A1 gene a variable phenotype ranging from mild to severe is seen, including adrenal failure, testis dysgenesis, androgen synthesis defects, hypospadias and anorchia with microphallus and infertility. We report the clinical, endocrinological and genetic characteristics of a patient with 46,XY DSD with a novel likely pathogenic missense variant in the NR5A1 gene. A retrospective evaluation of the medical history, physical examination, limited endocrinological laboratory analysis and genetic analysis with DSD gene panel testing was performed. A 1.5-month-old individual was referred with ambiguous genitalia. The karyotype was 46,XY. The endocrinological analyses were within normal male reference including a normal response of cortisol within an adrenocorticotropic hormone test. A novel heterozygous missense variant c.206G>C p.(Arg69Pro) in the NR5A1 gene was detected. This variant was present in mosaic form (~20%) in his unaffected father. Because another missense variant at the same position and other missense variants involving the same highly conserved codon have been reported, we consider this NR5A1 variant in this 46,XY DSD patient as likely pathogenic in accordance with the ACMG/AMP 2015 guidelines causing ambiguous genitalia but no adrenal insufficiency. This variant was inherited from the apparently unaffected mosaic father, which might have implications for the recurrence risk in this family. Learning points: The importance of performing trio (patient and parents) sequencing is crucial in pointing out the origin of inheritance. In a 46,XY differences of sex development patient, a normal adrenal function does not rule out an NR5A1 mutation. With the support of a dedicated overseas institute partnership, we could solve this complex clinical case by molecular diagnosis in a resource-limited setting.

Early Onset Marfan Syndrome with multivalvular insufficiency: Report from a tertiary hospital in Tanzania, and a review of the recurrent c.7606G>A p.0 variant in FBN1.

Marfan Syndrome is an autosomal dominant connective tissue disorder caused by mutations in the FBN1 gene. Early Onset Marfan Syndrome is at the severe end of the Marfan syndrome spectrum and is frequently associated with variants in exons 24-32 of the FBN1 gene. To the best of our knowledge, this is the first molecularly confirmed patient from Sub-Saharan Africa with Early Onset Marfan Syndrome who presented with tall stature, arachnodactyly, multivalvular insufficiency and ectopia lentis. Sequencing analysis of FBN1 gene revealed a pathogenic (class 5) heterozygous recurrent variant in exon 61 (c.7606G > A p.0NM_000138.3), which was up to now not associated with rapidly progressive Marfan syndrome with multivalvular insufficiency and congestive cardiac failure. This further supports the notion that the interplay of the given FBN1 mutation, one or more genetic modifiers and epigenetic and environmental factors defines the disease phenotype.

A Longitudinal Comparison of Environmental Sound Recognition in Adults With Hearing Aids Before and After Cochlear Implantation.

Purpose The aims of this study were (a) to longitudinally assess environmental sound recognition (ESR) before and after cochlear implantation in a sample of postlingually deafened adults and (b) to assess the extent to which spectro-temporal processing abilities influence ESR with cochlear implants (CIs). Method In a longitudinal cohort study, 20 postlingually deafened adults were tested with hearing aids on the Familiar Environmental Sound Test-Identification and AzBio sentences in quiet pre-CI and 6 months post-CI. A subset of 11 participants were also tested 12 months post-CI. Pre-CI spectro-temporal processing was assessed using the Spectral-temporally Modulated Ripple Test. Results Average ESR accuracy pre-CI (M = 63.60%) was not significantly different from ESR accuracy at 6 months (M = 65.40%) or 12 months (M = 69.09%) post-CI. In 11 participants (55%), however, ESR improved following implantation by 10.91 percentage points, on average. Pre-CI ESR correlated moderately and significantly with pre-CI and 12-month post-CI AzBio scores, with a trend toward significance for AzBio performance at 6 months. Pre-CI spectro-temporal processing was moderately associated with ESR at 6 and 12 months post-CI but not with speech recognition post-CI. Conclusions The present findings failed to demonstrate an overall significant improvement in ESR following implantation. Nevertheless, more than half of our sample showed some degree of improvement in ESR. Several environmental sounds were poorly identified both before and after implantation. Spectro-temporal processing ability prior to implantation appears to predict postimplantation performance for ESR. These findings indicate the need for greater attention to ESR following cochlear implantation and for developing individualized targets for ESR rehabilitation. Supplemental Material https://doi.org/10.23641/asha.13876745.

Carpenter syndrome in a patient from Tanzania.

Carpenter syndrome (acrocephalopolysyndactyly type II) is a rare autosomal recessive disorder. It was clinically diagnosed in a female baby with polysyndactyly and craniosynostosis in a referral clinic in Northern Tanzania. In the RAB23 gene, a previously described homozygous variant c.82C>T p.(Arg28*) was detected that results in a premature stop codon. Both parents were demonstrated to be heterozygous carriers of this variant. Herewith, its pathogenicity is proved. A literature search suggests this is the first molecularly confirmed case of Carpenter syndrome in continental Africa.

Inauguration of the Tanzania Society of Human Genetics: Biomedical Research in Tanzania with Emphasis on Human Genetics and Genomics.

Human genetics research and applications are rapidly growing areas in health innovations and services. African populations are reported to be highly diverse and carry the greatest number of variants per genome. Exploring these variants is key to realize the genomic medicine initiative. However, African populations are grossly underrepresented in various genomic databases, which has alerted scientists to address this issue with urgency. In Tanzania, human genetics research and services are conducted in different institutions on both communicable and noncommunicable diseases. However, there is poor coordination of the research activities, often leading to limited application of the research findings and poor utilization of available resources. In addition, contributions from Tanzanian human genetics research and services are not fully communicated to the government, national, and international communities. To address this scientific gap, the Tanzania Society of Human Genetics (TSHG) has been formed to bring together all stakeholders of human genetics activities in Tanzania and to formally bring Tanzania as a member to the African Society of Human Genetics. This article describes the inauguration event of the TSHG, which took place in November 2019. It provides a justification for its establishment and discusses presentations from invited speakers who took part in the inauguration of the TSHG.

Absence of GP130 cytokine receptor signaling causes extended Stüve-Wiedemann syndrome.

The gene IL6ST encodes GP130, the common signal transducer of the IL-6 cytokine family consisting of 10 cytokines. Previous studies have identified cytokine-selective IL6ST defects that preserve LIF signaling. We describe three unrelated families with at least five affected individuals who presented with lethal Stüve-Wiedemann-like syndrome characterized by skeletal dysplasia and neonatal lung dysfunction with additional features such as congenital thrombocytopenia, eczematoid dermatitis, renal abnormalities, and defective acute-phase response. We identified essential loss-of-function variants in IL6ST (a homozygous nonsense variant and a homozygous intronic splice variant with exon skipping). Functional tests showed absent cellular responses to GP130-dependent cytokines including IL-6, IL-11, IL-27, oncostatin M (OSM), and leukemia inhibitory factor (LIF). Genetic reconstitution of GP130 by lentiviral transduction in patient-derived cells reversed the signaling defect. This study identifies a new genetic syndrome caused by the complete lack of signaling of a whole family of GP130-dependent cytokines in humans and highlights the importance of the LIF signaling pathway in pre- and perinatal development.

Two cases of Prune Belly Syndrome from Kagera Region Tanzania.

Prune Belly Syndrome is a rare congenital disorder with unknown aetiology, consisting of a triad of abdominal muscle wall weakness, undescended testes, and urinary tract abnormalities. We are unaware of any preceding report of Prune Belly Syndrome in Tanzania, and here we describe two cases reported in Kagera region. The first case is a 2 month old boy with the triad of Prune Belly Syndrome along with pectus carinatum who died due to septicaemia. This case posed a diagnostic challenge at birth and during the natal period. Paucity of comprehensive knowledge of congenital malformations at the peripheral health facilities may have also contributed to the diagnostic challenge in the first place. The second case is a neonate who was referred to regional referral hospital where he was diagnosed with Prune Belly Syndrome at the age of four weeks. Because of limited capacity to manage congenital malformations at the regional referral hospital, he was referred to an urologist at the zonal referral hospital. However, inadequacies in supporting systems to the parents compounded care of the neonate with Prune Belly Syndrome. High index of Prune Belly Syndrome suspicion is needed in a resource limited setting in order to timely make diagnosis. There is also a need to strengthen institutional and individual's capacity for prenatal screening to detect congenital anomalies at an early stage of foetus development. Multidisciplinary management approach is necessary in order to improve the quality of life for patients with Prune Belly Syndrome. Psychosocial and medical support systems should be put in place in order to enhance preparedness for patient care in resource limited settings including equipping the referral hospital with different specialists and ensuring availability of basic investigations for patients.

Ellis-van Creveld syndrome in a patient from Tanzania.

We report an African infant with Ellis-van Creveld (EVC) syndrome. EVC syndrome is a chondral and ectodermal dysplasia with autosomal recessive transmission. The baby presented with polydactyly, short limbs and atrioventricular septal defect, but was withdrawn from clinical follow up for the first year of life. Initial hematological abnormalities could not be explained and normalized later. EVC syndrome was confirmed by genetic analysis that showed two pathogenic mutations in the EVC2 gene, c.653_654del, p.Val218Glyfs*12 in exon 5, and c.2710C>T, p.Gln904* in exon 16. The variant c.653_654del; p.Val218Glyfs*12 in exon 5 has not been described before. Our review of medical literature suggested this is the first molecularly confirmed case of EVC syndrome in sub-Saharan Africa.

Paroxysmal Kinesigenic Dyskinesia: First Molecularly Confirmed Case from Africa.

Background: Paroxysmal kinesigenic dyskinesia (PKD) is a movement disorder, with an excellent response to carbamazepine treatment. It has been described in various populations, but not yet in an African population. Case report: In a patient who reported to clinic with side effects of carbamazepine, PRRT2 gene screening was performed based on a clinical history compatible with PKD. A common PRRT2 mutation was identified in this patient, hereby the first genetically confirmed PRRT2-associated PKD in Africa. Discussion: Reporting genetic confirmation of an unusual movement disorder from an equally unusual location shows the wide geographical distribution of PRRT2-associated disease. It also illustrates recognizability of this treatable disorder where the easiest accessible diagnostic tool is neurological history and examination.

Camurati-Engelmann disease: a case report from sub-Saharan Africa.

Camurati-Engelmann disease is a rare autosomal dominant inherited condition belonging to the group of craniotubular hyperostosis with characteristic radiological features of the diaphyses of the long bones and the skull. A 35-year-old female is reported presenting with bone pain and waddling gait, since the age of 20 years. Motor activities were limited since the age of 10 years. Palpable bones, muscle weakness and protrusion of eyes were noted. Radiologically, hyperostosis of long bones was seen. Based on history, clinical and radiological features Camurati-Engelmann disease was diagnosed. Sequence analysis of the transforming growth factor ß1 (TGFB1) gene revealed a missense mutation (c.652C>T; p.Arg218Cys). She is the first molecularly confirmed case in sub-Saharan Africa. It is emphasized that Camurati-Engelmann disease is included in the differential diagnosis of persistent bone pain, but also of abnormal childhood motor development in order to avoid unnecessary investigations and inadequate management.

Respiratory Failure due to Severe Obesity and Kyphoscoliosis in a 24-Year-Old Male with Molecularly Confirmed Prader-Willi Syndrome in Tertiary Hospital in Northern Tanzania.

Obesity, mild intellectual disability, hypotonia, poor sucking, cryptorchidism in males, hypogonadism, and kyphoscoliosis are common features of Prader-Willi syndrome (PWS). We report a case who had severe respiratory complications due to extreme obesity and kyphoscoliosis, which are important causes of morbidity and mortality, and discuss management. Furthermore, this is the first molecularly confirmed PWS case in Sub-Saharan Africa outside South Africa.

Fibrodysplasia ossificans progressiva with minor unilateral hallux anomaly in a sporadic case from Northern Tanzania with the common ACVR1c.617G>A mutation.

Fibrodysplasia ossificans progressiva is a rare autosomal dominantly inherited disorder of connective tissue caused by mutations in the gene encoding for ACVR1/ALK2, a bone morphogenetic protein type I receptor. It is mainly characterized by congenital malformations of the great toes and the formation of qualitatively normal bone in extra-skeletal sites leading to severe disability and eventually death. We present a sporadic case from Northern Tanzania with a minor unilateral hallux anomaly and the common ACVR1 c.617G>A mutation.

Loss-of-function mutations in PNPLA6 encoding neuropathy target esterase underlie pubertal failure and neurological deficits in Gordon Holmes syndrome.

CONTEXT: Gordon Holmes syndrome (GHS) is characterized by cerebellar ataxia/atrophy and normosmic hypogonadotropic hypogonadism (nHH). The underlying pathophysiology of this combined neurodegeneration and nHH remains unknown. OBJECTIVE: We aimed to provide insight into the disease mechanism in GHS. METHODS: We studied a cohort of 6 multiplex families with GHS through autozygosity mapping and whole-exome sequencing. RESULTS: We identified 6 patients from 3 independent families carrying loss-of-function mutations in PNPLA6, which encodes neuropathy target esterase (NTE), a lysophospholipase that maintains intracellular phospholipid homeostasis by converting lysophosphatidylcholine to glycerophosphocholine. Wild-type PNPLA6, but not PNPLA6 bearing these mutations, rescued a well-established Drosophila neurodegenerative phenotype caused by the absence of sws, the fly ortholog of mammalian PNPLA6. Inhibition of NTE activity in the LßT2 gonadotrope cell line diminished LH response to GnRH by reducing GnRH-stimulated LH exocytosis, without affecting GnRH receptor signaling or LHß synthesis. CONCLUSION: These results suggest that NTE-dependent alteration of phospholipid homeostasis in GHS causes both neurodegeneration and impaired LH release from pituitary gonadotropes, leading to nHH.

A 3-base pair deletion, c.9711_9713del, in DMD results in intellectual disability without muscular dystrophy.

We have identified a deletion of 3 base pairs in the dystrophin gene (DMD), c.9711_9713del, in a family with nonspecific X-linked intellectual disability (ID) by sequencing of the exons of 86 known X-linked ID genes. This in-frame deletion results in the deletion of a single-amino-acid residue, Leu3238, in the brain-specific isoform Dp71 of dystrophin. Linkage analysis supported causality as the mutation was present in the 7.6 cM linkage interval on Xp22.11-Xp21.1 with a maximum positive LOD score of 2.41 (MRX85 locus). Molecular modeling predicts that the p.(Leu3238del) deletion results in the destabilization of the C-terminal domain of dystrophin and hence reduces the ability to interact with ß-dystroglycan. Correspondingly, Dp71 protein levels in lymphoblastoid cells from the index patient are 6.7-fold lower than those in control cell lines (P=0.08). Subsequent determination of the creatine kinase levels in blood of the index patient showed a mild but significant elevation in serum creatine kinase, which is in line with impaired dystrophin function. In conclusion, we have identified the first DMD mutation in Dp71 that results in ID without muscular dystrophy.

Subtelomeric chromosomal rearrangements in a large cohort of unexplained intellectually disabled individuals in Indonesia: A clinical and molecular study.

CONTEXT: Unbalanced subtelomeric chromosomal rearrangements are often associated with intellectual disability (ID) and malformation syndromes. The prevalence of such rearrangements has been reported to be 5-9% in ID populations. AIMS: To study the prevalence of subtelomeric rearrangements in the Indonesian ID population. MATERIALS AND METHODS: We tested 436 subjects with unexplained ID using multiplex ligation dependent probe amplification (MLPA) using the specific designed sets of probes to detect human subtelomeric chromosomal imbalances (SALSA P070 and P036D). If necessary, abnormal findings were confirmed by other MLPA probe kits, fluorescent in situ hybridization or Single Nucleotide Polymorphism array. RESULTS: A subtelomeric aberration was identified in 3.7% of patients (16/436). Details on subtelomeric aberrations and confirmation analyses are discussed. CONCLUSION: This is the first study describing the presence of subtelomeric rearrangements in individuals with ID in Indonesia. Furthermore, it shows that also in Indonesia such abnormalities are a prime cause of ID and that in developing countries with limited diagnostic services such as Indonesia, it is important and feasible to uncover the genetic etiology in a significant number of cases with ID.

p.Ser252Trp and p.Pro253Arg mutations in FGFR2 gene causing Apert syndrome: the first clinical and molecular report of Indonesian patients.

Apert syndrome (AS) is a rare autosomal dominant disorder characterised by craniosynostosis and limb malformations, and is associated with congenital heart disease and other systemic malformations, including intellectual disability. We report two Indonesian patients with AS, in whom molecular analysis detected p.Ser252Trp (c.755C>G) and p.Pro253Arg (c.758C>G) mutations in the fibroblast growth factor receptor 2 (FGFR2) gene, respectively. Although the syndrome has been frequently described, this is the first clinical report of AS confirmed by molecular analysis in Indonesia. The difference in severity of clinical features in the two patients may be consistent with a genotype-phenotype correlation of the FGFR2mutation. The management of individuals with AS is best achieved within a multidisciplinary setting. However, in most developing countries, early intervention may be delayed due to late diagnosis, a lack of facilities and financial constraints. This report underpins the benefits of early diagnosis for AS management.

Mutations in MED12 cause X-linked Ohdo syndrome.

Ohdo syndrome comprises a heterogeneous group of disorders characterized by intellectual disability (ID) and typical facial features, including blepharophimosis. Clinically, these blepharophimosis-ID syndromes have been classified in five distinct subgroups, including the Maat-Kievit-Brunner (MKB) type, which, in contrast to the others, is characterized by X-linked inheritance and facial coarsening at older age. We performed exome sequencing in two families, each with two affected males with Ohdo syndrome MKB type. In the two families, MED12 missense mutations (c.3443G>A [p.Arg1148His] or c.3493T>C [p.Ser1165Pro]) segregating with the phenotype were identified. Upon subsequent analysis of an additional cohort of nine simplex male individuals with Ohdo syndrome, one additional de novo missense change (c.5185C>A [p.His1729Asn]) in MED12 was detected. The occurrence of three different hemizygous missense mutations in three unrelated families affected by Ohdo syndrome MKB type shows that mutations in MED12 are the underlying cause of this X-linked form of Ohdo syndrome. Together with the recently described KAT6B mutations resulting in Ohdo syndrome Say/Barber/Biesecker/Young/Simpson type, our findings point to aberrant chromatin modification as being central to the pathogenesis of Ohdo syndrome.

Mowat-Wilson syndrome: the first clinical and molecular report of an indonesian patient.

Mowat-Wilson syndrome (OMIM 235730) is a genetic condition characterized by moderate-to-severe intellectual disability, a recognizable facial phenotype, and multiple congenital anomalies. The striking facial phenotype in addition to other features such as severely impaired speech, hypotonia, microcephaly, short stature, seizures, corpus callosum agenesis, congenital heart defects, hypospadias, and Hirschsprung disease are particularly important clues for the initial clinical diagnosis. All molecularly confirmed cases with typical MWS have a heterozygous loss-of-function mutation in the zinc finger E-box protein 2 (ZEB2) gene, also called SIP1 (Smad-interacting protein 1) and ZFHX1B, suggesting that haploinsufficiency is the main pathological mechanism. Approximately 80% of mutations are nonsense and frameshift mutations (small insertions or deletions). About half of these mutations are located in exon eight. Here, we report the first Indonesian patient with Mowat-Wilson syndrome confirmed by molecular analysis.

Assessment of left ventricular geometrical patterns and function among hypertensive patients at a tertiary hospital, Northern Tanzania.

BACKGROUND: With hypertension, the cardiovascular system changes to adapt to the varying neuro-humoral and hemodynamic changes and this may lead to the development of different left ventricular geometric patterns, each carrying a different risk profile for major adverse cardiovascular events. METHODS: Using a consecutive sampling technique, a cross-sectional, prospective, hospital based study was done and two hundred and twenty seven (227) hypertensive patients were studied. RESULTS: The distribution of different abnormal LV geometrical patterns was 19.8%, 28.2%, 22% for concentric remodelling, concentric hypertrophy and eccentric hypertrophy respectively. With echocardiographic criteria, the proportion of patients with left ventricular hypertrophy (LVH) was higher when left ventricular mass (LVM) was indexed to height(2.7) than to body surface area (70.0% vs. 52.9%). Duration of hypertension markedly influenced the type of LV geometry with normal LV geometry predominating in early hypertension and abnormal geometrical patterns predominating in late hypertension. The left ventricular fractional shortening decreased with duration of hypertension and was common in patients with eccentric hypertrophy. Age of the patient, systolic blood pressure, duration of hypertension and body mass index were found to be independent predictors left ventricular hypertrophy. CONCLUSION: About 70% of hypertensive patients had abnormal geometry existing in different patterns. Eccentric hypertrophy had more of clinical and echocardiographic features suggestive of reduced left ventricular systolic function. Hypertensive patients should be recognized as a heterogeneous population and therefore stratifying them into their respective LV geometrical patterns is useful as way of assessing their risk profile as well as instituting appropriate management.