Prenatal presentation of a rare genetic disorder: a clinical, autopsy and molecular correlation

Walker Warburg syndrome (WWS) lies at the severe end of the spectrum of the congenital muscular dystrophies. WWS is a congenital disorder of the O-glycosylation that disrupts in the post-translation modification of dystroglycan proteins. WWS is characterized by the involvement of the central nervous system and rarely by multisystem involvement. Next-generation sequencing discovered that multiple genes are associated with this disorder. FKTN is the rarest cause of WWS. We describe a clinical-autopsy report of a molecularly- confirmed WWS case presenting with ventriculomegaly, agenesis of the corpus callosum with a novel phenotype of Dandy-Walker malformation and unilateral multi-cystic kidney. The whole-exome sequencing confirmed a homozygous variant (c.411C>A) in the FKTN gene with a premature termination codon. This case emphasizes the importance of detailed postnatal phenotyping through an autopsy in any pregnancy with antenatally identified malformations. Obstetricians, pediatricians as well as fetal medicine experts need to counsel the parents and focus on preserving the appropriate sample for genetic testing. WWS, though rare deserves testing especially in the presence of positive family history. Dandy-Walker malformation is a novel feature and expands the phenotypic spectrum

Tyrosine hydroxylase deficiency - Clinical insights and a novel deletion in TH gene in an Indian patient

Tyrosine hydroxylase deficiency is a rare autosomal recessive, treatable disorder of neurotransmission. Fewer than 100 cases have been reported so far. We present a case of a 10‐month‐old infant who was symptomatic since 5 months of age and who received an initial diagnosis of infantile tremor syndrome. She presented with rest tremor, decreased facial expression, global hypokinesia, and later on with oculogyric crisis and dystonia. This diagnosis was revised after confirmation of tyrosine hydroxylase deficiency by CSF neurotransmitter analysis. Genetic studies revealed one previously reported missense variant, p.Thr399Met, and another large deletion starting upstream of exon 1 and encompassing exon 1. She was started on treatment with escalating doses of L‐Dopa/Carbidopa, with folinic acid supplementation. At 3.5 years of age, her cognitive functioning and development is appropriate for age. There is complete subsidence of dystonia and oculogyric episodes. She has occasional chorieform movements which appear to be drug related

Lysinuric protein intolerance presenting with recurrent hyperammonemic encephalopathy

BACKGROUND: Lysinuric protein intolerance is an inherited disorder of transport of cationic amino acids, causing amino aciduria. CASE CHARACTERISTICS: A 3-year-old boy with 12 month history of episodic change in behavior (decreased sleep, poor interaction), stunted growth and hyperammonemia. OUTCOME: Genetic analysis revealed a homozygous mutation, c.158C>T (p.Ser53Leu) in exon 1 of SLC7A7 gene. With appropriate management of hyperammonemia episodes, his neurodevelopmental outcome is normal. MESSAGE: Lysinusic protein intolerance is a potentially treatable disorder and should not to be missed

Neurological Deterioration in Three Siblings: Exploring the Spectrum of Argininemia

Argininemia or hyperargininemia is a urea cycle disorder caused by deficiency of the enzyme arginase 1. It is inherited in an autosomal recessive fashion. It commonly leads to spastic diplegia in childhood, but other important features include cognitive deterioration and epilepsy. Unlike other disorders of the urea cycle, hyperammonemia is not prominent. The authors report three siblings with genetically proven argininemia who presented with diverse phenotypes but with spasticity being a common feature. Sibling 1 developed motor regression in early childhood, sibling 2 developed delayed motor milestones from early infancy, whereas sibling 3 had global developmental delay in late infancy after a period of normal development. All siblings had mild hyperammonemia only. Early recognition is imperative, not only to initiate ammonia scavenging therapy which may lead to definite clinical improvement, but also to provide genetic counselling. Keywords: Arginase deficiency; Argininemia; Spastic diplegia; Urea cycle disorders

Citrin deficiency: A treatable cause of acute psychosis in adults

Citrin deficiency is an autosomal recessive genetic disorder caused by a defect in the mitochondrial aspartate/glutamate antiporter, citrin. The disorder manifests either as neonatal intra-hepatic cholestasis or occurs in adulthood with recurrent hyperammonemia and neuropsychiatric disturbances. It has a high prevalence in the East Asian population, but is actually pan-ethnic. We report the case of a 26-year-old male patient presenting with episodes of abnormal neuro-psychiatric behavior associated with hyperammonemia, who was diagnosed to be having citrin deficiency. Sequencing of the SLC25A13 gene revealed two novel mutations, a single base pair deletion, c. 650delT (p.Phe217SerfsFNx0133) in exon 7, and a missense mutation, c. 869T>C (p.Ile290Thr) in exon 9. Confirmation of the diagnosis allowed establishment of the appropriate management. The latter is an essential pre-requisite for obtaining a good prognosis as well as for family counseling

Mutation–proved Clouston syndrome in a large Indian family with a variant phenotype

Hereditary ectodermal dysplasias, a group of disorders affecting skin, hair, nails, and teeth, consist of two main clinical forms – hypohidrotic and hidrotic. Clouston syndrome is a hidrotic ectodermal dysplasia characterized by a triad of generalized hypotrichosis, palmoplantar hyperkeratosis, and nail dystrophy. This paper reports a large Indian family with Clouston syndrome but with the absence of palmoplantar keratoderma, one of the features of the typical triad, thus representing phenotypic heterogeneity, in spite of the presence of a common known mutation in GJB6 gene (p.Gly11Arg)

Expanding the disease phenotype of ADSSL1-associated myopathy in non-Korean patients

Adenylosuccinate synthase (ADSSL1) is a muscle specific enzyme involved in the purine nucleotide cycle and responsible for the conversion of inosine monophosphate to adenosine monophosphate. Since 2016, when mutations in the ADSSL1 gene were first described to be associated with an adult onset distal myopathy, nine patients with compound heterozygous variants in the ADSSL1 gene, all of Korean origin, have been identified. Here we report a novel ADSSL1 mutation and describe two sporadic cases of Turkish and Indian origin. Many of the clinical features of both patients and muscle histopathology and muscle MRI findings, were in accordance with previously reported findings in the adult onset distal myopathy individuals. However, one of our patients presented with progressive, proximally pronounced weakness, severe muscle atrophy and early contractures. Thus, mutations in ADSSL1 have to be considered in patients with both distal and proximal muscle weakness and across various ethnicities. (C) 2020 Published by Elsevier B.V