Recessive Disease Research Articles

Cognition trajectory in Duchenne muscular dystrophy

BackgroundDuchenne muscular dystrophy (DMD) is an X-linked recessive disease brought on by genetic changes that alter the dystrophin (DYS) protein. There has been growing evidence that children with DMD have been at higher risk of developing symptoms of neurodevelopmental disorders. We aimed at defining the cognitive difficulties and their categories in patients with DMD, compared to healthy controls, and assessing their relation with the functional severity. This work was a multi-center, observational, case–control study conducted on DMD patients. Age and sex-matched healthy subjects with no neurologic, psychiatric, or medical comorbidities were included as normal controls.ResultsThere was a statistically significant difference in cognitive patterns between the studied groups. We have observed a significant relationship between cognitive difficulties and functional severity assessment in our patients. There was a statistically significant difference between the studied cases regarding basic characteristics and correlation between cognitive functions and demographic data.ConclusionsThe decline in cognitive functions in DMD patients compared to healthy controls was established. Education was the most affected domain in patients, with more speech delay and dropping out of school. Therefore, it was recommended to establish cognitive screening as a routine in the evaluation and follow-up of DMD children.

Biallelic variants in SLC26A2 cause multiple epiphyseal dysplasia-4 by disturbing chondrocyte homeostasis

BackgroundMultiple epiphyseal dysplasia-4 (MED-4, MIM 226900) is a rare autosomal recessive disease characterized by disproportionate height and early onset osteoarthritis of the lower limbs. MED-4 is caused by homozygous or compound heterozygous pathogenic variants in the SLC26A2 gene. However, the underlying pathogenic mechanisms in chondrocytes remains unknown. This study aimed to identify the pathogenic variants within a MED-4 family and explore the molecular etiology of this condition in human primary chondrocyte cells.MethodsClinical data were recorded and peripheral blood samples were collected for analysis. Whole exome sequencing (WES) and bioinformatic analyses were performed to determine causative variants. Wild-type SLC26A2 and corresponding mutant expression plasmids were constructed and transfected into human primary chondrocytes. The expression and subcellular distribution of SLC26A2 protein in chondrocytes were detected by immunoblotting and immunofluorescence. Effects of these variants on chondrocytes viability and apoptosis were measured by Cell Counting Kit-8 (CCK-8) assay. Expression of genes related to cartilage homeostasis was subsequently analyzed by quantitative real-time polymerase chain reaction (qRT-PCR).ResultsWe identified two compound heterozygous variants c.1020_1022delTGT(p.Val341del) and c.1262 T > C(p.Ile421Thr) in the SLC26A2 gene in the patients. Mutant SLC26A2Val341del and SLC26A2Ile421Thr proteins were distributed in relatively few cells and were observed only within the nucleus. The viability of chondrocytes with the SLC26A2 variant group was similar to the wild-type (WT) group. However, the protein expressions of SLC26A2Val341del and SLC26A2Ile421Thr were decreased compared with SLC26A2WT. Expression levels of matrix metallopeptidase 13 (MMP13), α-1 chain of type X collagen (COL10A1), and Runt-related transcription factor 2 (RUNX2) were significantly decreased in the variant group. However, aggrecan (ACAN) expression was higher in the variant group than the WT group.ConclusionsOverall, our data demonstrate that the variants p.Val341del and p.Ile421Thr in SLC26A2 cause MED-4 and that these two variants promote chondrocyte proliferation while inhibiting chondrocyte differentiation.

Aneuploidy rates and likelihood of obtaining a usable embryo for transfer among in vitro fertilization cycles using preimplantation genetic testing for monogenic disorders and aneuploidy compared with in vitro fertilization cycles using preimplantation genetic testing for aneuploidy alone

ObjectiveTo compare aneuploidy rates among IVF cycles using preimplantation genetic testing for monogenic disorders (PGT-M) and aneuploidy (PGT-A) compared to IVF cycles using PGT-A alone, and to determine the likelihood of obtaining at least one usable embryo in cycles using PGT-M+PGT-A compared with cycles using PGT-A alone. DesignRetrospective cohort study SubjectsAll IVF cycles for patients aged 18-45 undergoing PGT-A with or without concurrent PGT-M at a single genetics laboratory from November 2019 to March 2023. ExposureUse of PGT-M+PGT-A versus use of PGT-A alone Main Outcome MeasuresPer-cycle aneuploidy rate stratified by age, and per-cycle likelihood of obtaining at least one usable embryo stratified by age and inheritance pattern of monogenic disease ResultsA total of 72,522 IVF cycles were included; 4,255 cycles (5.9%) using PGT-M+PGT-A and 68,267 cycles (94.1%) using PGT-A alone. The PGT-M+PGT-A group was younger than the PGT-A alone group (<35 years old: 56.1% vs 30.5%, p<0.001). The majority of PGT-M cycles were performed for autosomal dominant pathogenic variants (42.4%), followed by autosomal recessive (36.5%), X-linked dominant (13.3%), and X-linked recessive (7.5%). The median number of embryos biopsied was higher in PGT-A alone compared to PGT-M+PGT-A cycles for patients aged <35, but it was equivalent in all other age groups. Age stratified aneuploidy rates did not significantly differ between PGT-M+PGT-A compared with PGT-A alone cycles. The probability of having a usable embryo declined with increasing age across all inheritance patterns. Compared with PGT-A alone, PGT-M+PGT-A cycles for patients aged ≤40 across all inheritance patterns were significantly less likely to yield a usable embryo (p<0.01), except in cycles for autosomal recessive diseases in the 38-40 age group and X-linked recessive diseases in the 35-37 age group. There were no consistent differences seen between groups in patients over 40. Cycles for patients with autosomal dominant diseases had the lowest likelihood of yielding a usable embryo for patients aged <43. ConclusionIVF cycles using PGT-M+PGT-A have similar age-specific aneuploidy rates to those using PGT-A alone. Cycles for patients ≤ 40 using PGT-M+PGT-A are significantly less likely to yield a usable embryo compared to those using PGT-A alone.

Recent Advance in Disease Modifying Therapies for Spinal Muscular Atrophy

Abstract Spinal muscular atrophy (SMA) is an autosomal recessive motor neuron disease characterized by progressive weakness and atrophy of skeletal muscles. With homozygous survival motor neuron 1 (SMN1) gene mutation, all SMA patients have at least one copy of the SMN2 gene, which provides an opportunity for drug targeting to enhance SMN expression. Current three disease modifying drugs, including nusinersen, onasemnogene abeparvovec, and risdiplam, have demonstrated impressive effectiveness in SMA treatment. Nusinersen is an antisense oligonucleotide targeting SMN2 pre-messenger RNA (mRNA) to modify alternative splicing and is effective in SMA children and adults, administrating via intermittent intrathecal injection. Onasemnogene abeparvovec is an adeno-associated viral vector carrying human SMN1 gene, featuring intravenous injection once in a lifetime for SMA patients less than 2 years of the age. Risdiplam is a small molecule also targeting SMN2 pre-mRNA and is effective in SMA children and adults with administration via oral intake once per day. Patients with SMA should receive these disease modifying therapies as soon as possible to not only stabilize disease progression, but potentially obtain neurological improvement. The development in these therapies has benefited patients with SMA and will potentially provide insight in future drug discovery for other neurodegenerative diseases.

Advances in vestibular function and rehabilitation of large vestibular aqueduct syndrome

Large vestibular aqueduct syndrome（LVAS） is a common recessive hereditary hearing loss disease, and some patients may also experience vestibular dysfunction. With the wide application of cochlear implant（CI） and the development of vestibular medicine, the pathophysiological mechanism of LVAS and the influence mechanism of CI on vestibular function are gradually elucidated. Consequently, the evaluation and rehabilitation of vestibular dysfunction function have also become research hotspots. This article reviews studies on vestibular function and related rehabilitation in patients with large vestibular aqueduct syndrome.

A model organism pipeline provides insight into the clinical heterogeneity of TARS1 loss-of-function variants

Aminoacyl-tRNA synthetases (ARSs) are ubiquitously expressed, essential enzymes that complete the first step of protein translation: ligation of amino acids to cognate tRNAs. Genes encoding ARSs have been implicated in myriad dominant and recessive phenotypes, the latter often affecting multiple tissues but with frequent involvement of the central and peripheral nervous systems, liver, and lungs. Threonyl-tRNA synthetase (TARS1) encodes the enzyme that ligates threonine to tRNATHR in the cytoplasm. To date, TARS1 variants have been implicated in a recessive brittle hair phenotype. To better understand TARS1-related recessive phenotypes, we engineered three TARS1 missense variants at conserved residues and studied these variants in Saccharomyces cerevisiae and Caenorhabditis elegans models. This revealed two loss-of-function variants, including one hypomorphic allele (R433H). We next used R433H to studythe effects of partial loss of TARS1 function in a compound heterozygous mouse model (R432H/null). This model presents with phenotypes reminiscent of patients with TARS1 variants and with distinct lung and skin defects. This study expands the potential clinical heterogeneity of TARS1-related recessive disease, which should guide future clinical and genetic evaluations of patient populations.

Unilateral multicystic dysplastic kidney complicated with urinary tract infection by E. coli in a premature newborn

Autosomal recessive polycystic kidney disease is a renal development anomaly characterized by cystic transformation in renal parenchyma. ARPKD is more common in children. We present the case of a premature newborn, female, 36-37 weeks gestation, small for gestational age (SGA) originating from a completely unmonitored pregnancy, diagnosed upon admission to the clinic with unilateral multicystic dysplastic kidney. The condition complicated by a urinary tract infection with E. coli. This newborn displayed no clinical symptoms, was carefully monitored during hospitalization, and received antibiotic treatment. Antenatal ultrasound screening can aid in the early diagnosis of congenital anomalies and determining the appropriate course of action.

Genetic landscape and clinical outcomes of autosomal recessive polycystic kidney disease in Kuwait

BackgroundAutosomal recessive polycystic kidney disease (ARPKD), a rare genetic disorder characterized by kidney cysts, shows complex clinical and genetic heterogeneity. This study aimed to explore the genetic landscape of ARPKD in Kuwait and examine the intricate relationship between its genes and clinical presentation to enhance our understanding and contribute towards more efficient management strategies for ARPKD. MethodsThis study recruited 60 individuals with suspected ARPKD from 44 different families in Kuwait. The participants were of different ethnicities and aged 0–70 years. Additionally, 33 were male, 15 were female, and 12 had indeterminant sex due to congenital anomalies. Comprehensive clinical data were collected. Mutations were identified by next-generation whole exome sequencing and confirmed using Sanger sequencing. ResultsOf the 60 suspected ARPKD cases, 20 (33.3 %) died within hours of birth or by the end of the first month of life and one (1.7 %) within 12 months of birth. The remaining 39 (65.0 %) cases were alive, at the time of the study, and exhibited diverse clinical features related to ARPKD, including systematic hypertension (5.0 %), pulmonary hypoplasia (11.7 %), dysmorphic features (40.0 %), cardiac problems (8.3 %), cystic liver (5.0 %), Potter syndrome (13.3 %), developmental delay (8.3 %), and enlarged cystic kidneys (100 %). Twelve mutations, including novel truncating mutations, were identified in 31/60 cases (51.7 %) from 17/44 families (38.6 %). Additionally, 8/12 (66.7 %) mutations were in the PKHD1 gene, with the remaining four in different genes: NPHP3, VPS13P, CC2D2A, and ZNF423. ConclusionsThis study highlights the spectrum of clinical features and genetic mutations of patients with ARPKD in Kuwait. It highlights the necessity for personalized approaches to improve ARPKD diagnosis and treatment, offering crucial insights into managing ARPKD.

Pseudotumor Cerebri with Familial Mediterranean Fever in an Adult Patient

Familial Mediterranean fever is an autosomal recessive disease characterized by recurrent episodes of fever, peritonitis, pleuritis and arthritis. Neurological involvement in FMF is rare but serious. Headache, seizures, demyelinating lesions, stroke, posterior reversible leukoencephalopathy syndrome, aseptic meningitis and cranial neuropathy have been reported in the literature. In this paper, we present a combination of FMF and pseudotumor cerebri in an adult patient.

Exploration of Ca⁺² Binding Affinity to DEAD-Box Helicase through Computational Approaches

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an occasional catastrophic fatal autosomal dominant or recessive inherited disease that affects an estimated ≈1-5000/10000 people including children, adolescents and young adults, which may cause syncope, abrupt cardiac death during exercise and emotional state. Calmodulin (CALM) functions as a messenger protein of intracellular Ca+2 signaling in cardiomyocytes that transmits complex Ca+2 ions to the proteins involved in cardiac contraction, and its activation is also facilitated by the binding of Ca+2 ions. CALM structure contains 4 EF-hands, each EF-hand holds a single Ca+2 ion (designated as, CA149, CA150, CA151 and CA152). In this study, we performed detailed in_silico analysis of normal and mutated (ASN53ILE) CALM structures to characterize their Ca+2 binding abilities. In CALM-ASN53ILE-Pep-IQ complex, we observed a binding shift of P68(Pep-IQ) as compared to CALM-WT. The root mean square deviation was in the range of 0.4-1 nm for all the systems, while root mean square fluctuation values were in the range of 0.3-0.6 nm for bound versus unbound proteins. Hydrogen-bond profiling was significantly different between CALM-WT and CALM-ASN53ILE over the course of simulation. We observed an introduction of β1 and β2-segment between α1- α2 and α3- α4 along with the movement of C-terminal approximately to 1800 in the apo-CALM-ASN53ILE. Thus, we propose that, ASN53ILE has a pathological impact in the progression of CPVT due to structural and conformational changes in CALM and its binding affinity towards P68(Pep-IQ). The current study may constitute a valuable starting point for CPVT therapeutics through the involvement of CALM-ASN53ILE for designing novel inhibitors to cope with neuropathological disorder.

A case report of autosomal recessive polycystic kidney disease with noncompaction of ventricular myocardium: coincidence or different manifestations of ciliopathy?

BackgroundAutosomal recessive polycystic kidney disease (ARPKD) is a rare inherited cystic disease characterized by bilateral renal cyst formation and congenital liver fibrosis. Cardiovascular disorders such as noncompaction of ventricular myocardium (NVM) have not been reported with ARPKD.Case presentationA 5-month-old girl was examined after presenting with a fever and turbid urine for one day and was diagnosed as urinary tract infection. Urinary ultrasound showed multiple round, small cysts varying in size in both kidneys. Genetic testing revealed two heterozygous mutations and one exon deletion in the polycystic kidney and hepatic disease 1 gene, indicating a diagnosis of ARPKD. During hospitalization, she was found to have chronic heart failure after respiratory tract infection, with an ejection fraction of 29% and fraction shortening of 13%. When the patient was 15 months old, it was found that she had prominent trabeculations and deep intertrabecular recesses with the appearance of blood flow from the ventricular cavity into the intertrabecular recesses by echocardiography. The noncompaction myocardium was 0.716 cm and compaction myocardium was 0.221 cm (N/C = 3.27), indicating a diagnosis of NVM. Liver and kidney function remained normal during four-year follow-up.ConclusionsThis is the first report of NVM in a patient with ARPKD. It is unsure if the coexistence of NVM and ARPKD is a coincidence or they are different manifestations of ciliary dysfunction in the heart and kidneys.

Unveiling cystinosis in India

BackgroundCystinosis, a rare autosomal recessive disease, stems from genetic alterations in the CTNS gene, leading to a malfunction of lysosomal ‘cystinosin’ protein. This dysfunction causes intracellular cystine accumulation, resulting in nephropathic and ocular abnormalities. Cystinosis is relatively rare in Asian countries, partly due to underreporting and lack of awareness, and cases often lack sufficient genetic evidence to support their diagnosis. This study presents a descriptive case series involving four Indian patients with cystinosis, elucidating clinical and genetic aspects.MethodsAll four patients underwent comprehensive ophthalmic evaluations. The corneal cystine crystal (CCC) score was determined using anterior segment optical coherence tomography (AS-OCT) and in vivo confocal microscopy (IVCM). Genetic testing was performed using whole exome sequencing (WES).ResultsCorneal crystal deposition, a hallmark of cystinosis, was evident in all cases. Systemic analysis revealed manifestations such as polyuria, bony abnormalities, growth retardation, hypothyroidism, and developmental delay. Genetic testing in two patients identified a homozygous pathogenic variant c.18_21delGACT (p.Thr7PhefsX7) in the CTNS gene, previously reported to cause cystinosis in different ethnic populations.ConclusionsOur case series sheds light on underrepresented cases of cystinosis in the Indian population. The rarity of this condition poses diagnostic challenges, leading to delayed or inaccurate diagnoses. AS-OCT can serve as a viable alternative to IVCM for assessing corneal crystal density status in cystinosis. Timely recognition and management are crucial in preventing complications, and the inclusion of genetic testing can expedite cystinosis diagnosis.

Comprehensive assessment of recessive, pathogenic AARS1 alleles in a humanized yeast model reveals loss-of-function and dominant-negative effects.

Alanyl-tRNA synthetase 1 (AARS1) encodes the enzyme that ligates tRNA molecules to alanine in the cytoplasm, which is required for protein translation. Variants in AARS1 have been implicated in early-onset, multi-system recessive phenotypes and in later-onset dominant peripheral neuropathy; to date, no single variant has been associated with both dominant and recessive diseases raising questions about shared mechanisms between the two inheritance patterns. AARS1 variants associated with recessive disease are predicted to result in null or hypomorphic alleles and this has been demonstrated, in part, via yeast complementation assays. However, pathogenic alleles have not been assessed in a side-by-side manner to carefully scrutinize the strengths and limitations of this model system. To address this, we employed a humanized yeast model to evaluate the functional consequences of all AARS1 missense variants reported in recessive disease. The majority of variants showed variable loss-of-function effects, ranging from no growth to significantly reduced growth. These data deem yeast a reliable model to test the functional consequences of human AARS1 variants; however, our data indicate that this model is prone to false-negative results and is not informative for genotype-phenotype studies. We next tested missense variants associated with no growth for dominant-negative effects. Interestingly, K81T AARS1, a variant implicated in recessive disease, demonstrated loss-of-function and dominant-negative effects, indicating that certain AARS1 variants may be capable of causing both dominant and recessive disease phenotypes.

Editing of eIF(iso)4E.c confers resistance against Turnip mosaic virus in Brassica rapa

Turnip mosaic virus (TuMV) constitutes one of the primary diseases affecting Brassica rapa, severely impacting its production and resulting in crop failures in various regions worldwide. Recent research has demonstrated the significance of plant translation initiation factors, specifically the eIF4E and eIF4G family genes, as essential recessive disease resistance genes. In our study, we conducted evolutionary and gene expression studies, leading us to identify eIF(iso)4E.c as a potential TuMV-resistant gene. Leveraging CRISPR/Cas9 technology, we obtained mutant B. rapa plants with edited eIF(iso)4E.c gene. We confirmed eIF(iso)4E.c confers resistance against TuMV through phenotypic observations and virus content evaluations. Furthermore, we employed ribosome profiling assays on eif(iso)4e.c mutant seedlings to unravel the translation landscape in response to TuMV. Interestingly, we observed a moderate correlation between the fold changes in gene expression at the transcriptional and translational levels (R2 = 0.729). Comparative analysis of ribosome profiling and RNA-seq data revealed that plant–pathogen interaction, and MAPK signaling pathway–plant pathways were involved in eIF(iso)4E.c-mediated TuMV resistance. Further analysis revealed that sequence features, coding sequence length, and normalized minimal free energy, influenced the translation efficiency of genes. Our study highlights that the loss of eIF(iso)4E.c can result in a highly intricate translation mechanism, acting synergistically with transcription to confer resistance against TuMV.

Ocular Changes in Cystic Fibrosis: A Review.

Cystic fibrosis (CF), also known as mucoviscidosis, is the most common autosomal recessive genetic disease in the Caucasian population, with an estimated frequency of 1:2000-3000 live births. CF results from the mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) gene localized in the long arm of chromosome 7. The product of CFTR gene expression is CFTR protein, an adenosine triphosphate (ATP)-binding cassette (ABC) transporter that regulates the transport of chloride ions (Cl-) across the apical cell membrane. Primary manifestations of CF include chronic lung and pancreas function impairment secondary to the production of thick, sticky mucus resulting from dehydrated secretions. It is well known that CF can cause both anterior and posterior ocular abnormalities. Conjunctival and corneal xerosis and dry eye disease symptoms are the most characteristic manifestations in the anterior segment. In contrast, the most typical anatomical and functional changes relating to the posterior segment of the eye include defects in the retinal nerve fiber layer (RNFL), vascular abnormalities, and visual disturbances, such as reduced contrast sensitivity and abnormal dark adaptation. However, the complete background of ophthalmic manifestations in the course of CF has yet to be discovered. This review summarizes the current knowledge regarding ocular changes in cystic fibrosis.

Harlequin mice exhibit cognitive impairment, severe loss of Purkinje cells and a compromised bioenergetic status due to the absence of Apoptosis Inducing Factor

The functional integrity of the central nervous system relies on complex mechanisms in which the mitochondria are crucial actors because of their involvement in a multitude of bioenergetics and biosynthetic pathways. Mitochondrial diseases are among the most prevalent groups of inherited neurological disorders, affecting up to 1 in 5000 adults and despite considerable efforts around the world there is still limited curative treatments.Harlequin mice correspond to a relevant model of recessive X-linked mitochondrial disease due to a proviral insertion in the first intron of the Apoptosis-inducing factor gene, resulting in an almost complete depletion of the corresponding protein. These mice exhibit progressive degeneration of the retina, optic nerve, cerebellum, and cortical regions leading to irremediable blindness and ataxia, reminiscent of what is observed in patients suffering from mitochondrial diseases.We evaluated the progression of cerebellar degeneration in Harlequin mice, especially for Purkinje cells and its relationship with bioenergetics failure and behavioral damage.For the first time to our knowledge, we demonstrated that Harlequin mice display cognitive and emotional impairments at early stage of the disease with further deteriorations as ataxia aggravates. These functions, corresponding to higher-order cognitive processing, have been assigned to a complex network of reciprocal connections between the cerebellum and many cortical areas which could be dysfunctional in these mice.Consequently, Harlequin mice become a suitable experimental model to test innovative therapeutics, via the targeting of mitochondria which can become available to a large spectrum of neurological diseases.

The Utility of Long-Read Sequencing in Diagnosing Genetic Autosomal Recessive Parkinson's Disease: a genetic screening study.

Mutations within the genes PRKN and PINK1 are the leading cause of early onset autosomal recessive Parkinson's disease (PD). However, the genetic cause of most early-onset PD (EOPD) cases still remains unresolved. Long-read sequencing has successfully identified many pathogenic structural variants that cause disease, but this technology has not been widely applied to PD. We recently identified the genetic cause of EOPD in a pair of monozygotic twins by uncovering a complex structural variant that spans over 7 Mb, utilizing Oxford Nanopore Technologies (ONT) long-read sequencing. In this study, we aimed to expand on this and assess whether a second variant could be detected with ONT long-read sequencing in other unresolved EOPD cases reported to carry one heterozygous variant in PRKN or PINK1. ONT long-read sequencing was performed on patients with one reported PRKN/PINK1 pathogenic variant. EOPD patients with an age at onset younger than 50 were included in this study. As a positive control, we also included EOPD patients who had already been identified to carry two known PRKN pathogenic variants. Initial genetic testing was performed using either short-read targeted panel sequencing for single nucleotide variants and multiplex ligation-dependent probe amplification (MLPA) for copy number variants. 48 patients were included in this study (PRKN "one-variant" n = 24, PINK1 "one-variant" n = 12, PRKN "two-variants" n = 12). Using ONT long-read sequencing, we detected a second pathogenic variant in six PRKN "one-variant" patients (26%, 6/23) but none in the PINK1 "one-variant" patients (0%, 0/12). Long-read sequencing identified one case with a complex inversion, two instances of structural variant overlap, and three cases of duplication. In addition, in the positive control PRKN "two-variants" group, we were able to identify both pathogenic variants in PRKN in all the patients (100%, 12/12). This data highlights that ONT long-read sequencing is a powerful tool to identify a pathogenic structural variant at the PRKN locus that is often missed by conventional methods. Therefore, for cases where conventional methods fail to detect a second variant for EOPD, long-read sequencing should be considered as an alternative and complementary approach.

Next generation sequencing identifies WNT signalling as a significant pathway in Autosomal Recessive Polycystic Kidney Disease (ARPKD) manifestation and may be linked to disease severity

IntroductionAutosomal Recessive Polycystic Kidney Disease (ARPKD) is a rare paediatric disease primarily caused by sequence variants in PKHD1. ARPKD presents with considerable clinical variability relating to the type of PKHD1 sequence variant, but not its position. Animal models of Polycystic Kidney Disease (PKD) suggest a complex genetic landscape, with genetic modifiers as a potential cause of disease variability. MethodsTo investigate in an unbiased manner the molecular mechanisms of ARPKD and identify potential indicators of disease severity, Whole Exome Sequencing (WES) and RNA-Sequencing (RNA-Seq) were employed on human ARPKD kidneys and age-matched healthy controls. ResultsWES confirmed the clinical diagnosis of ARPKD in our patient cohort consisting of ten ARPKD kidneys. Sequence variant type, nor position of PKHD1 sequence variants, was linked to disease severity. Sequence variants in genes associated with other ciliopathies were detected in the ARPKD cohort, but only PKD1 could be linked to disease severity. Transcriptomic analysis on a subset of four ARPKD kidneys representing severe and moderate ARPKD, identified a significant number of genes relating to WNT signalling, cellular metabolism and development. Increased expression of WNT signalling-related genes was validated by RT-qPCR in severe and moderate ARPKD kidneys. Two individuals in our cohort with the same PKHD1 sequence variants but different rates of kidney disease progression, with displayed transcriptomic differences in the expression of WNT signalling genes. ConclusionARPKD kidney transcriptomics highlights changes in WNT signalling as potentially significant in ARPKD manifestation and severity, providing indicators for slowing down the progression of ARPKD.

COL2A1-АССОЦИИРОВАННАЯ ПРОГРЕССИРУЮЩАЯ ПСЕВДОРЕВМАТОИДНАЯ ДИСПЛАЗИЯ: КЛИНИЧЕСКОЕ НАБЛЮДЕНИЕ

Modern medical scientific sources offer descriptions of cases of hereditary bone dysplasias occurring under the guise of rheumatoid arthritis (RA). These include the progressive pseudorheumatoid dysplasia (PPRD), an autosomal recessive disease caused by defects in the CCN6 gene, as well as autosomal dominant forms of pseudorheumatoid dysplasia associated with variants in the COL2A1 gene. Though there are no references to pseudorheumatoid dysplasia case observations in available domestic sources. This Article represents a discussion over the bibliographic sources on PPRD and a clinical case observation of a patient initially observed for RA but diagnosed subsequently with an autosomal dominant form of bone dysplasia caused by a de novo variant in the COL2A1 gene.

Cortical impairment and reduced muscle mass in children and young adults with nephropathic cystinosis.

Nephropathic cystinosis is an orphan autosomal recessive lysosomal storage disease characterized by a deficiency of cystinosin, a cystine transporter protein, leading to tissue damage, primarily in the kidney and cornea. With the introduction of cystine-depleting therapy with cysteamine and the possibility to survive to adulthood, new challenges of skeletal complications are a concern, with sparse data available regarding bone development. The aim of the current study was to gain more information on bone density and geometry in these patients. Fifty-one patients (29 males, 22 females) with genetically proven nephropathic cystinosis were clinically evaluated with a medical history, physical examination, grip strength measurements, and biochemical and imaging studies. Bone mineral density, bone geometry, and muscle cross sectional area were measured, and muscle was evaluated. Results were compared with age- and gender-specific reference data. Z-scores for height (mean [M] = -1.75, standard deviation [SD] = 1.43), weight (M = -1.67, SD = 1.29), and BMI (M = -0.98, SD = 1.29) were lower than reference data. Medullary cross-sectional area (CSA) and cortical density z-scores were not compromised (M = 0.12, SD = 1.56 and M = -0.25, SD = 1.63, respectively), but cortical CSA z-scores and Strength-Strain Index (SSI) were reduced (M = -2.16, SD = 1.08, M = -2.07, SD = 1.08). Muscular deficits were reflected by reduced z-scores for muscle CSA (M = -2.43, SD = 1.27) and grip strength (M = -3.01, SD = 1.10), along with jump force (34% lower than reference value). Multiple regression analyses indicated an association of muscle mass with medullary CSA and SSI, but not with cortical CSA. While bone density parameters were normal, bone geometry was altered, resulting in a thinner cortex with possible impact on bone strength. Muscle weakness be partially responsible for altered bone geometry and could provide a potential treatment target.