Homozygous Missense Mutation In Exon Research Articles

Generation and characterization of a Stargardt’s disease-specific induced pluripotent stem cell line (LVPEIi008-A) with a homozygous nonsense mutation in exon 44 of ABCA4

The Stargardt’s Disease, Type 1 (STGD1) is associated with the loss of function mutations in ABCA4. This gene codes for a retina-specific, ATP-binding cassette (ABC) family transporter, involved in the transport of the key visual cycle intermediate, all-trans-retinaldehyde (atRAL), across the photoreceptor cell membranes. Here, we report the establishment of a patient-specific, iPSC line (LVPEIi008-A), that carries a homozygous nonsense mutation at (c.6088C > T) position, within exon 44 of ABCA4. The patient-specific skin fibroblasts were reprogrammed using episomal plasmids and the stably expanding iPSC line expressed the key stemness and pluripotency markers, maintained its chromosomal integrity and tested negative for mycoplasma.

Multimodal imaging and genetic analysis in a rare case of autosomal recessive bestrophinopathy in India

We report a rare case of autosomal recessive bestrophinopathy (ARB) in India, where multimodal imaging and genetic analysis were done. Optical coherence tomography revealed a thickened Verhoeff’s membrane in both eyes and genetic analysis revealed a homozygous missense mutation in exon 4. To the best of our knowledge, this is the first case of ARB in India where genetic analysis has been done.

Novel STXBP2 Mutation Causing Familial Haemophagocytic Lymphohistiocytosis Type 5 in a Preterm Neonate with Fatal Outcome: A Case Report

Familial Haemophagocytic Lymphohistiocytosis (FHL) is an autosomal recessive disorder characterised by a hyperinflammatory state due to widespread infiltration of organs with macrophages and lymphocytes. Haemophagocytic Lymphohistiocytosis (HLH) presents with fever, hepatosplenomegaly, cytopenia, hyperferritinemia and haemophagocytosis in the reticuloendothelial tissues causing multi organ failure with fatal outcome. HLH is rare in neonates with an incidence of 1 in 50,000 to 1 in 150,000. FHL is diagnosed based on clinical criteria, biochemical abnormalities, and genetic mutation. Mutations involving the gene STXBP2 contributes to around 10% of cases of FHL and there are only a few cases of FHL5 reported from India. A six-week-old neonate presented with sepsis which was unresponsive to antibiotics. Persistent fever, bicytopenia, hepatosplenomegaly and laboratory tests made us suspect HLH, and evaluate further with whole exome sequencing. FHL5 was diagnosed based on the identification of homozygous missense mutation in exon 3 of STXBP2 gene (chr19: 7642803_7642803delA). The baby succumbed to sepsis and multi organ failure. HLH should be considered in the differential diagnosis of any sick infant who presents with prolonged fever, sepsis unresponsive to antibiotics and an unusual clinical course.

Moyamoya Disease Associated with a Deficiency of Complement Component 6

ObjectivesComplement component 6 (C6) deficiency is a very rare genetic defect that leads to significantly diminished synthesis, secretion, or function of C6. In the current report, we demonstrate a previously undescribed, homozygous missense mutation in exon 17 of the C6 gene (c.2545A>G p.Arg849Gly) in a 35-year-old Japanese woman with moyamoya disease and extremely low levels of CH50 (<7.0 U/mL). Materials and MethodsThe complement gene analysis using hybridization capture-based next generation sequencing was performed. CH50 was determined in patient's plasma mixed with plasma from a healthy donor or purified human C6 protein. Western blot was performed on patient's plasma using polyclonal antibodies against C6, with healthy donor's plasma and purified human C6 protein as positive controls while C6-depleted human serum as a negative control. The carriage of ring finger protein 213 variant (c.14576G>A p.Arg4859Lys), a susceptibility gene for moyamoya disease, was examined by direct sequencing. ResultsCH50 mixing test clearly showed a deficiency pattern, being rescued by addition of only 1% healthy donor's plasma or 1 μg/mL purified human C6 protein (1/50-1/100 of physiological concentration). Western blot revealed the absence of C6 protein in the patient's plasma, confirming a quantitative deficiency of C6. The ring finger protein 213 variant was not detected. ConclusionsOur data implies that unrecognized complement deficiencies would be harbored in cerebrovascular diseases with unknown etiologies.

Clinical and diagnostic characteristics of complex III mitopathy due to novel BCS1L gene mutation in a Saudi patient

BackgroundOf the many types of mitochondrial diseases, mutations affecting BCS1L gene are regarded as chief cause of the defective mitochondrial complex-III, affecting normal mitochondrial functioning, and leading to wide variety of phenotypes.Case presentationIn this case report we describe a novel genotype linked to a unique phenotype in a Saudi patient born of a consanguineous marriage. Detailed genetic analysis and whole genome sequencing identified a novel homozygous missense mutation in exon 5 c.712A > G (p.Ser328Gly) of the BCS1L gene, with predicted deleterious effects on the functioning AAA+-ATPase domain of the protein characterized by distinct clinical presentation associated with profound multisystem involvement, conductive hearing loss, absent external auditory canal, low posterior hair line, short neck, micro and retrognathia, over riding fingers, rocker bottom foot, small phallus with bilateral absent testis (empty scrotum) and intolerable lactic acidosis.ConclusionsA pathogenic effect of this novel BCS1L mutation was reflected in the patient with his failure to thrive and a complex clinical and metabolic phenotype.

Syndrome of Congenital Insulin Resistance Caused by a Novel INSR Gene Mutation

Mutations in the INSR gene result in rare inherited syndromes causing insulin resistance, such as leprechaunism (Donohue syndrome), Rabson-Mendenhall syndrome and insulin resistance type A. Leprechaunism is an autosomal recessive disorder associated with extreme insulin resistance that leads to hyperinsulinemia, impaired glucose homeostasis, fasting hypoglycemia and postprandial hyperglycemia. Impaired insulin action causes prenatal and postnatal growth retardation. Lipoatrophy, dysmorphic facies, hypertrichosis, macrogenitosomia and hypertrophy of internal organs are also present. A male infant with congenital insulin resistance was born at term after a normal pregnancy with a weight of 1905 g (<3 c), a length of 48 cm (<3 c), and an Apgar score of 10. Intrauterine growth retardation, transient hypoglycemia, pneumonia, urinary tract infection and heart defects [patent foramen ovale (PFO); patent ductus arteriosus (PDA)] were diagnosed after birth. At 5 weeks of age, he was admitted to the regional hospital with severe fever, diarrhea and dehydration. Hyperglycemia was observed (672 mg/dL), and insulin was administered. He was referred to a hospital at 7 weeks of age for suspected neonatal diabetes and hypertrophic cardiomyopathy. The physical examination revealed a loud systolic heart murmur, tachycardia, tachypnea, dysmorphic facies, hypertrichosis, acanthosis nigricans, hypotonia, swollen nipples and enlarged testicles. Glycemic fluctuations (50-250 mg/dL) were observed. The serum insulin concentration was high (maximum 1200 IU/mL) at normoglycemia. Ultrasound of the heart confirmed progressive hypertrophic cardiomyopathy. Leprechaunism was confirmed by genetic analysis of INSR, in which a novel c.320C>G; p. Thr107Arg homozygous missense mutation was found in exon 2.

Hemophagocytic lymphohistiocytosis, what about hair?

A 1-month-old boy, born to nonconsanguineous parents, without notable family health history, presented with febrile pancytopenia and splenomegaly. Clinical examination disclosed no other anomaly, notably no neurological alteration. His initial complete blood count showed normocytic anemia (hemoglobin 105 g/L), thrombocytopenia (84 × 109/L), and neutropenia (0.8 × 109/L) without lymphopenia. Upon worsening of this pancytopenia, associated with persistent fever despite antibiotics, a bone marrow aspirate revealed no blasts but the presence of histiocytes with hemophagocytosis (Image 1A). High serum triglycerides, ferritin, and lactic dehydrogenase were observed at respectively 3.3 mmol/L, 71 000 μg/L, and 788 U/L together with hypofibrinogenemia (1.1 g/L). Molecular tests for toxoplasmosis, HSV, EBV, CMV, HHV6, and parvovirus B19 were negative. Clinical examination revealed the presence of partial albinism with silver-gray hair. This feature associated to the biological anomalies, evoked a diagnosis of Griscelli or Chediak Higashi syndrome. However, bone marrow cells did not contain giant cytoplasmic granulations. Moreover, microscopic analysis of hair revealed clumps of melanin of various sizes irregularly distributed throughout the hair shaft, suggestive of Griscelli syndrome (Image 1B,C). Cerebrospinal fluid (CSF) analysis revealed hyperproteinorachia (0.73 g/L) and 20/μL leucocytes (92% lymphocytes CD4+, CD3+, DR+, CD25−) in favor of asymptomatic central nervous system hemophagocytic lymphohistiocytosis (HLH). Sequencing of the RAB27 gene in a blood sample finally revealed a homozygous missense mutation in exon 3, confirming the diagnosis of type 2 Griscelli syndrome.1 Corticosteroid therapy was initiated followed by alemtuzumab administration. The patient then underwent a haplo-identical allogeneic hematopoietic stem cell transplantation and is well 8 months later. Children with GS2 indeed present with partial albinism, associated with hemophagocytic lymphohistiocytosis. RAB27A deficiency is responsible for a defective exocytosis of cytotoxic granules from T cells and natural killer cells, which may cause secondary immune overactivation leading to HLH. In the absence of treatment, the evolution is rapidly fatal. Although poorly codified, treatment consists in suppression of the triggering factor, control of HLH with chemotherapy or immunotherapy followed by an allo-HSCT.2 The pejorative evolution of this pathology makes its early recognition essential. Thus, children presenting with HLH must systematically benefit from a search for partial albinism. The presence of silver-gray hair makes necessary microscopic examination. The authors declare that they have no conflict of interest. ME and EC performed analyses. BLC, AH and CT treated the patient. BLC, MCB and ME wrote the manuscript.

MFSD8 Mutation Causing Neuronal Ceroid Lipofuscinosis Type 7 in a Bangladeshi Patient: A Rare Case Report and Review of Literature

The neuronal ceroid lipofuscinoses (NCLs) are a heterogeneous group of inherited neurodegenerative disorders. Their unifying clinical hallmarks are seizures, visual loss, myoclonus, ataxia, cognitive and motor regression which lead to early death. Based on the clinical onset of symptoms NCL-affected individuals have been classified into six categories. Fourteen genetic forms of NCL (CLN1 to CLN14) have been identified so far. The variant late-infantile form of the disease has been linked to CLN5, CLN6, CLN7 (MFSD8) and CLN8 mutations.We report a patient of 9 years from a consanguineous family who presented with progressive visual loss and seizures. Clinical Exome sequencing reveals a homozygous missense mutation in exon 11 of the MFSD8 gene (c.1235C>T, p.Pro412Leu). To our knowledge, this is the first report of MFSD8 gene mutation in a Bangladeshi patient with variant late-infantile NCL. This study also provides information regarding the phenotypic and molecular spectrum of CLN7 disease.

A novel homozygous TPM1 mutation in familial pediatric hypertrophic cardiomyopathy and in silico screening of potential targeting drugs.

Familial hypertrophic cardiomyopathy (HCM) is the most common genetic cardiac disease. While sarcomeric gene mutations explain many HCM cases, the genetic basis of about half of HCM cases remains elusive. Here we aimed to identify the gene causing HCM in a non-consanguineous Saudi Arabian family with affected family members and a history of sudden death. The impact of the identified mutation on protein structure and potential drug targets were evaluated in silico. Triplets (two HCM subjects and one patent ductus arteriosus (PDA) case) and unaffected parents were screened by targeted next-generation sequencing (NGS) for 181 candidate cardiomyopathy genes. In silico structural and functional analyses, including protein modeling, structure prediction, drug screening, drug binding, and dynamic simulations were performed to explore the potential pathogenicity of the variant and to identify candidate drugs. A homozygous missense mutation in exon 1 of TMP1 (assembly GRCh37-chr15: 63340781; G>A) was identified in the triplets [two HCM and one patent ductus arteriosus (PDA)] that substituted glycine for arginine at codon 3 (p.Gly3Arg). The parents were heterozygous for the variant. The mutation was predicted to cause a significant and deleterious change in the TPM1 protein structure that slightly affected drug binding, stability, and conformation. In addition, we identified several putative TPM1-targeting drugs through structure-based in silico screening. TPM1 mutations are a common cause of HCM and other congenital heart defects. To date, TPM1 has not been associated with isolated PDA; to our knowledge, this is the first report of the homozygous missense variation p.Gly3Arg in TPM1 associated with familial autosomal recessive pediatric HCM and PDA. The identified candidate TPM1 inhibitors warrant further prospective investigation.

SUN-LB19 Novel Homozygous Mutation in BMP1 Causing Osteogenesis Imperfecta

Background: Osteogenesis imperfecta (OI) is characterized by bone fragility and increased fracture susceptibility. Most mutations occur in COL1A1 and COL1A2 genes. Rarely, mutations in BMP1 have been reported in association with OI type XIII. Disease severity is generally more severe when the mutation affects both gene products encoded by BMP1 that serve as procollagenases: bone morphogenic protein 1 and mammalian tolloid (mTLD) [1]. Clinical Case: A 7-year-old Hispanic boy, with speech and gross motor delays, sustained five bilateral tibial fractures with minimal trauma since age 2.5 years. At age 6 years, he developed severe back pain after a minor fall. Diffuse spinal osteopenia and multiple vertebral compression fractures (VCF) at T9, L1, L3 were identified radiographically, with progressive vertebral height loss in the ensuing 9 months. Fatigue was reported after walking >10 min, with difficulty running and climbing stairs. There was no family history of musculoskeletal disorders.Stature was consistently between 10-15th% for age. Subtle facial dysmorphism included micrognathia and small chin, with patchy blue-gray sclerae, and normal dentition. The lumbar spine was tender to percussion. Gait was slow and antalgic with external rotation of the right hip.Laboratory evaluation revealed normal serum calcium, iPTH, magnesium, phosphate, 25-hydroxyvitamin D and alkaline phosphatase for age. P1NP was slightly high (193 µg/L, 30-110 µg/L) and CTX was slightly low (554 pg/mL, n: 574-1849 pg/mL), the latter being atypical for OI. Total hip BMD (adjusted for height Z-score) was normal (Z-score = 1.76) and adjusted femoral neck BMD was high (Z-score = 2.67). VCFs precluded assessment of lumbar spine BMD. Genomic analysis revealed a homozygous missense mutation in exon 4 of BMP1 resulting in an amino acid substitution (c. C505T; p.Arg169Cys) in both the bone morphogenetic protein 1 and mTLD gene products of BMP1. The mutation is predicted to be damaging to both proteins, and associated with this rare form of OI. Conclusion: We report a novel homozygous mutation in BMP1 identified in a child with autosomal recessive OI. Unlike most forms of OI, patients with type XIII often have normal or increased BMD [1], making a correlation between BMD and fracture risk difficult. While bisphosphonates (BP) may help reduce recurrent fractures and provide symptomatic relief, the broad phenotypic spectrum and concern for further increasing BMD complicate management. A high resolution peripheral quantitative CT scan to assess bone microarchitecture and quality may aid in the decision of BP therapy. As evidence is limited on the effectiveness of BP in this rare form of OI, it is important to consider each case individually.1.Sangsin, A., et al., Two novel compound heterozygous BMP1 mutations in a patient with osteogenesis imperfecta: a case report. BMC Med Genet, 2017. 18(1): p. 25.

Congenital Leptin Deficiency and Leptin Gene Missense Mutation Found in Two Colombian Sisters with Severe Obesity.

Background: Congenital leptin deficiency is a recessive genetic disorder associated with severe early-onset obesity. It is caused by mutations in the leptin (LEP) gene, which encodes the protein product leptin. These mutations may cause nonsense-mediated mRNA decay, defective secretion or the phenomenon of biologically inactive leptin, but typically lead to an absence of circulating leptin, resulting in a rare type of monogenic extreme obesity with intense hyperphagia, and serious metabolic abnormalities. Methods: We present two severely obese sisters from Colombia, members of the same lineal consanguinity. Their serum leptin was measured by MicroELISA. DNA sequencing was performed on MiSeq equipment (Illumina) of a next-generation sequencing (NGS) panel involving genes related to severe obesity, including LEP. Results: Direct sequencing of the coding region of LEP gene in the sisters revealed a novel homozygous missense mutation in exon 3 [NM_002303.3], C350G>T [p.C117F]. Detailed information and clinical measurements of these sisters were also collected. Their serum leptin levels were undetectable despite their markedly elevated fat mass. Conclusions: The mutation of LEP, absence of detectable leptin, and the severe obesity found in these sisters provide the first evidence of monogenic leptin deficiency reported in the continents of North and South America.

Next-generation sequencing identifies a homozygous mutation in ACADVL associated with pediatric familial dilated cardiomyopathy.

Pediatric familial dilated cardiomyopathy (DCM) is a rare and severe heart disease. The genetics of familial DCM are complex and include over 100 known disease-causing genes, but many causative genes are unknown. We aimed to identify the causative gene for DCM in a consanguineous Saudi Arabian family with affected family members and a history of sudden death. Affected (two children) and unaffected (one sibling and the mother) family members were screened by next-generation sequencing (NGS) for 181 candidate DCM genes and underwent metabolic screening. Fifty-seven clinically annotated controls and 46 DCM cases were then tested for the identified mutation. In silico structural and functional analyses including protein modeling, structure prediction and dynamic simulations were performed. A homozygous missense mutation in exon 15 of the acyl-CoA dehydrogenase very long chain gene (ACADVL; chr17:7127303; G>A) was identified in affected subjects that substituted histidine for arginine at codon 450 (p.R450H). The variant was heterozygous in the mother and unaffected sister. The mutation was absent in 57 clinically annotated controls and 48 pediatric DCM cases. The mutation was predicted to cause a significant and deleterious change in the ACADVL protein structure that affected drug binding, stability, and conformation. Metabolic screening confirmed VLCAD deficiency in affected individuals. The ACADVL R450H mutation is an uncommon cause of the DCM phenotype that appears to be autosomal recessive. Targeted NGS is useful for identifying the causative mutation(s) in familial DCM of unknown genetic cause.

Clinical and molecular characteristics of colombian patients with mucopolysaccharidosis IVA, and description of a new galns gene mutation

A study published in 2012 estimated incidence of MPS IVA, in 0.68 cases per 100, 000 live births in Colombia, and according to the Colombian Fund for High-Cost Diseases, in 2014 there were 15 people diagnosed with MPS IV. To enhance the knowledge of the disease in the country, we aimed to characterize clinical and molecular findings in 12 MPS IVA patients. Twelve patients were included in the study, with most patients of female gender (n = 7, 58,3%), age range 2 to 28 years, average weight 26 kg (17.6–43 kg), average height 97 cm (92–104 cm), average BMI 27.6 kg/m2 (19.92–47.65 kg/m2). Clinical findings were similar to those described in the literature. GALNS gene molecular analysis showed five homozygous missense mutations in exon 11 c.1156C > T or p.R386C, a single nonsense mutation in the heterozygous state c.974G > A p.W325, and heterozygous in exon 9 mutation of exon 3 c.280C > T p.R94C, missense variant reported by Ogawa in 1995 [17]. There was only one patient that presented a homozygous missense mutation in exon 9 c.901G > T p.G301C and four patients showed the heterozygous form. A heterozygous missense mutation in exon 5 c.425A > T p.H142L, which has not been previously reported, was found in a female patient, 2 years 11 months of age. The diagnosis algorithms that include molecular analysis, bioinformatic predictive tools, pharmacogenomics, and proteomics helps to improve the diagnosis, treatment, and prognosis of patients affected by MPS IVA.

Severe Insulin Resistance Due To C.576CG (P.I119M) Mutation In The Insr Gene: Case Report

ABSTRACT Objective: Severe insulin resistance is frequently associated with mutations in insulin signaling. Methods: We report here a 26-year-old woman with severe insulin resistance due to insulin receptorpathy. Results: This patient had asymptomatic hyperglycemia (hemoglobin A1c >10% [86 mmol/mol]), hyperinsulinemia, amenorrhea, hyperandrogenism, clitromegaly, loss of subcutaneous fat in the upper arms and thighs, and swelling in the hands and legs. Her body mass index was 19.8 kg/m2. Her adiponectin level was the highest ever reported by the laboratory (98.0 μg/mL). Her hyperglycemia was not associated with ketoacidosis, neuropathy, nephropathy, retinopathy, or vasculopathy. She was equally well with and without insulin therapy. She improved on metformin and drospirenone/ethinyl estradiol. Insulin receptor gene sequencing revealed a homozygous missense mutation in exon 2 (c.576C>G [p.I119M]). Conclusion: The clinical course illustrates a rare form of severe insulin resistance and its management challenges.

Novel missense mutation in the GALNS gene in an affected patient with severe form of mucopolysaccharidosis type IVA

Mucopolysaccharidosis type IVA (MPS IVA), also known as Morquio A, is an autosomal recessive disorder characterized by a deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS), which causes major skeletal and connective tissue abnormalities and affects multiple organ systems. In this study, one MPS IVA patient with a severe form from consanguine large Iranian family has been investigated. To find a mutation, all of the 14 exons and intron–exon junctions of GALNS gene were sequenced. Sequencing results were analyzed using bioinformatic analysis in order to predict probable pathogenic effect of the variant. One novel homozygous missense mutation in exon 5, c.542A>G (p.Y181C), was found in the proband. That was predicted as being probably pathogenic by bioinformatics analysis. Segregation and familial study confirmed this pathogenic mutation. In conclusion, we have identified the novel mutation responsible for MPS IVA in an Iranian patient to assist in the diagnosis, genetic counseling and prenatal diagnosis of the affected families.

Novel CFI mutation in a patient with leukocytoclastic vasculitis may redefine the clinical spectrum of Complement Factor I deficiency

Factor I is an important regulator of the complement system. Lack of Factor I causes uncontrolled activation of the complement system leading to consumption of C3. Complete deficiency of Factor I is a rare condition and only around 40 cases has been reported in the literature. The clinical presentation of Factor I deficiency varies and includes severe recurrent bacterial infections, glomerulonephritis and autoimmune diseases. The patient, a 28-years old woman with consanguineous parents, presented with recurrent leukocytoclastic vasculitis in the lower extremities with no associated systemic involvement, and without increased infection tendency. Initial testing showed low C3 concentration and a detailed complement evaluation absence of complement Factor I. Sequencing revealed a homozygous missense mutation in exon 2 of the CFI gene (SCV000221312). Even though the clinical symptoms of CFI mutations vary among patients sole association with leukocytoclastic vasculitis redefines the clinical spectrum of complete Factor I deficiency.

Genetic analysis of the UPB1 gene in two new Chinese families with β-ureidopropionase deficiency and the carrier frequency of the mutation c.977G>A in Northern China.

The purpose of the study was to investigate mutations of the UPB1 gene in two Chinese families with β-ureidopropionase deficiency and the heterozygous carrier frequency in Chinese. Genomic DNA was extracted from peripheral blood leukocytes from all available family members and 500 unrelated healthy controls. Then, all exons and flanking intron regions of the UPB1 gene were amplified by PCR and analyzed by direct sequencing in two patient-families. Finally, the carrier frequency of the c.977G>A (p.R326Q) mutation was identified by PCR restriction fragment length polymorphism in 500 healthy controls. The two patients had the same homozygous missense mutation in exon 9 (c.977G>A; p.R326Q), and the carrier frequency of this mutation was 2.8 % in the Northern Chinese population, which suggests that about 1:5,102 Chinese are expected to suffer from UPB1 deficiency. The c.977G>A (p.R326Q) is the most common mutation of the UPB1 gene in Chinese. The predicted incidence indicates that β-ureidopropionase deficiency is significantly underdiagnosed in the Chinese population. It should be necessary to add β-ureidopropionase deficiency to high-risk screening for the symptomatic patients group.

A novel missense mutation in HSD17B3 gene in a 46, XY adolescent presenting with primary amenorrhea and virilization at puberty

Deficiency of 17β-hydroxysteroid dehydrogenase type3 (17β-HSD3) isoenzyme which catalyzes the synthesis of testosterone from Δ4-androstenedione, is the cause of 46, XY disorders of sex development (DSD). 17β-HSD3 deficiency is a rare autosomal recessive disorder, which is caused by mutations in the HSD17B gene found on chromosome 9q22. Up to now, almost 33 mutations in the HSD17B3 gene have been reported. Here, we report a patient with a novel mutation in HSD17B3 gene leading to 17β-HSD3 deficiency. The patient was admitted because of primary amenorrhea and signs of virilization at puberty. The chromosome analysis showed a 46, XY karyotype. Hormonal evaluation revealed a high Δ4-androstenedione level with a low serum testosterone/androstenedione (T/A) ratio. Sequence analysis of HSD17B3 gene revealed the presence of a homozygous missense mutation in exon 11 resulting in a premature stop codon (p.Y287). Gonadectomy was performed after the molecular diagnosis and estrogen replacement therapy was initiated. With this report, we emphasize that 17β-HSD3 deficiency should be considered in virilized female patients at puberty if the T/A ratio is less than 0.8, and the molecular analysis should be performed for the precise diagnosis and genetic counseling.

Analysis of a hereditary protein C deficient consanguineous pedigree caused by Phe139Val homozygous mutation

To analyze genetic mutation and explore its molecular pathogenesis for an hereditary protein C (PC) deficient consanguineous pedigree. The pedigree included three generations and contained eight members. PC activity (PC:A), PC antigen (PC:Ag) and other coagulant parameters were detected for all family members. Protein C gene (PROC) include all the exons and intron exon boundaries were amplified by PCR for the proband, then analyzed by direct sequencing. Mutation sites were detected for the other family members. The PC:A and PC:Ag in the proband plasma were 20% (normal range 70% -140%) and 13.2% (normal range 70%-130%). A homozygous missense mutation g.6128T>G in exon 7 resulting in Phe139Val was identified in the proband. The PC:A and PC:Ag in her younger brother were 31% and 18.90%, Phe139Val homozygous was also found. The left family members were heterozygous for Phe139Val. Phe139Val homozygous missense mutation in exon 7 of PROC caused serious hereditary protein C deficiency. We speculated that homozygous mutation might be resulted from this consanguineous marriage.

Creatine deficiency syndrome. A treatable myopathy due to arginine–glycine amidinotransferase (AGAT) deficiency

We report two sisters, aged 11 and 6years, with AGAT deficiency syndrome (OMIM 612718) which is the least common creatine deficiency syndrome. They were born full-term to consanguineous parents and had moderate developmental delay. Examination showed an important language delay, a progressive proximal muscular weakness in the lower limbs with Gowers sign and myopathic electromyography. Investigations revealed undetectable guanidinoacetate and low level of creatine in plasma and urine, characteristic findings of AGAT deficiency syndrome. Brain magnetic resonance spectroscopy showed a markedly reduced level of creatine. Guanidinoacetate methyltransferase (GATM) gene sequencing revealed a homozygous missense mutation in exon 4:c.608A>C, (p.Tyr203Ser). Thirteen months after beginning the treatment with oral creatine monohydrate 200mg/kg/day, then 400mg/kg/day, there was a dramatic improvement in muscle strength with Gowers sign disappearance in both patients, and a mild improvement in language and cognitive functions. AGAT deficiency syndrome should be considered in all patients with language retardation and cognitive impairment associated to a myopathy of unknown etiology such that early diagnosis must lead to creatine supplementation to cure the myopathy and improve language and cognitive function.