Next-Generation Sequencing Identifies a Homozygous Nonsense p.Tyr370* Mutation of the TMC6 Gene in a Mexican Pedigree with Epidermodysplasia Verruciformis.

Epidermodysplasia verruciformis (EV) is a rare genodermatosis characterized by abnormal susceptibility to infection with b-genotype human papillomavirus (HPV) and a particular propensity to develop cutaneous malignancies. Clinical manifestations include flat, scaly, reddish hypo- and hyperpigmented macules, verruca-like papillomatous lesions, seborrheic keratosis- like lesions, and pink-red pityriasis versicolor-like lesions1.

Síndrome de Sjögren-Larsson: Reporte de caso pediátrico / Sjögren-Larsson syndrome: Pediatric case report

El síndrome de Sjogren-Larsson se caracteriza por retardo mental, ictiosis congènita y diplejía o cuadriplejía espástica. El defecto primario en este síndrome es la mutación del gen ALDH3A2, que codifica la enzima aldehído deshidrogenasa grasa y causa una deficiencia enzimática que produce una acumulación de alcoholes y aldehídos grasos en los tejidos que comprometen la integridad de la membrana celular, cuyos efectos pueden observarse en la piel, los ojos y el sistema nervioso central. El diagnóstico se realiza por medio de la cuantificación de la actividad de la enzima. Se describe el caso de una paciente con signos clínicos patognomónicos del síndrome de Sjogren-Larsson, cuyo diagnóstico se realizó por medio de la cuantificación de la actividad enzimática en un cultivo de fibroblastos. Además, tomando en cuenta el árbol genealógico de la paciente, se realizó el estudio en los padres y un hermano con signos sugestivos del síndrome de Sjogren-Larsson.

Sjogren-Larsson syndrome is characterized by congenital ichthyosis, mental retardation and spastic diplegia or quadriplegia. The primary defect in this syndrome is mutation of ALDH3A2 gen that codes for the fatty aldehyde dehydrogenase. Deficiency of this enzyme causes an accumulation of fatty alcohols and fatty aldehydes, leading to altered cell-membrane integrity. Skin, eyes, and the central nervous system are affected latter. The diagnosis is carried out through the cuantification of the enzyme activity.

[Sjögren-Larsson syndrome: Pediatric case report]. / Síndrome de Sjögren-Larsson: Reporte de caso pediátrico.

Sjogren-Larsson syndrome is characterized by congenital ichthyosis, mental retardation and spastic diplegia or quadriplegia. The primary defect in this syndrome is mutation of ALDH3A2 gen that codes for the fatty aldehyde dehydrogenase. Deficiency of this enzyme causes an accumulation of fatty alcohols and fatty aldehydes, leading to altered cell-membrane integrity. Skin, eyes, and the central nervous system are affected latter. The diagnosis is carried out through the cuantification of the enzyme activity. This case report describes the diagnosis of a clinical syndrome with symptoms of Sjogren-Larsson syndrome by the quantification of the enzymatic activity in a culture of fibroblasts. Also, taking into account the genealogy of the patient, the study was conducted in the parents and a brother with signs suggestive of Sjogren-Larsson syndrome.

El síndrome de Sjogren-Larsson se caracteriza por retardo mental, ictiosis congènita y diplejía o cuadriplejía espástica. El defecto primario en este síndrome es la mutación del gen ALDH3A2, que codifica la enzima aldehído deshidrogenasa grasa y causa una deficiencia enzimática que produce una acumulación de alcoholes y aldehídos grasos en los tejidos que comprometen la integridad de la membrana celular, cuyos efectos pueden observarse en la piel, los ojos y el sistema nervioso central. El diagnóstico se realiza por medio de la cuantificación de la actividad de la enzima. Se describe el caso de una paciente con signos clínicos patognomónicos del síndrome de Sjogren-Larsson, cuyo diagnóstico se realizó por medio de la cuantificación de la actividad enzimática en un cultivo de fibroblastos. Además, tomando en cuenta el árbol genealógico de la paciente, se realizó el estudio en los padres y un hermano con signos sugestivos del síndrome de Sjogren-Larsson.

A rapidly progressive defective spermatogenesis in a Mexican family affected by spino-bulbar muscular atrophy.

Spino-bulbar muscular atrophy (SBMA) is an X-linked recessive adult progressive disorder affecting motor neurons. It is caused by a poly-glutamine tract expansion in the androgen receptor (AR) which generates protein aggregates that cannot be processed by proteasomes. A secondary mild androgen resistance is developed by AR dysfunction and patients present endocrine abnormalities including gynecomastia and poor function of testosterone in tissues; however, normally they are fertile. In this report we describe a Mexican family with three affected brothers with primary infertility caused by a progressive impairment of spermatogenesis leading to azoospermia before 40 years of age. They presented common features associated to patients affected by SMBA, such as gynecomastia, high level of CPK, muscle cramps, fasciculations, muscle wastage, and impaired swallowing. Two intracytoplasmic sperm injection (ICSI) cycles were performed in one of the patients resulting in fertilization failure. Molecular analysis of AR gene exon 1 revealed 54 CAG repeats in DNA extracted from leukocytes in affected patients and 22 repeats in the fertile non-affected brother. Severe impaired spermatogenesis of rapid progression has not been associated before to SBMA. This is the first report of assisted reproduction techniques indicated by male infertility in patients with this rare disorder. Further studies are required to confirm the unusual result of intracytoplasmic sperm injection cycles. We discuss the implications and possible pathogenesis of these unique features of SBMA in this family.

Novel LIPA mutations in Mexican siblings with lysosomal acid lipase deficiency.

Lysosomal acid lipase (LAL) deficiency is an under-recognized lysosomal disease caused by deficient enzymatic activity of LAL. In this report we describe two affected female Mexican siblings with early hepatic complications. At two months of age, the first sibling presented with alternating episodes of diarrhea and constipation, and later with hepatomegaly, elevated transaminases, high levels of total and low-density lipoprotein cholesterol, and low levels of high-density lipoprotein. Portal hypertension and grade 2 esophageal varices were detected at four years of age. The second sibling presented with hepatomegaly, elevated transaminases and mildly elevated low-density lipoprotein and low high-density lipoprotein at six months of age. LAL activity was deficient in both patients. Sequencing of LIPA revealed two previously unreported heterozygous mutations in exon 4: c.253C>A and c.294C>G. These cases highlight the clinical continuum between the so-called Wolman disease and cholesteryl ester storage disease, and underscore that LAL deficiency represents a single disease with a degree of clinical heterogeneity.

Clinical and genetic characteristics of mexican patients with juvenile presentation of niemann-pick type C disease.

Niemann-Pick type C disease (NPC) is a rare lysosomal disease with a protean presentation, ranging from a fatal neonatal course with visceromegaly to an adult presentation with only neurological or psychiatric symptomatology. In this report we describe the genetic and clinical characteristics of 3 Mexican patients from different families with juvenile presentation of NPC. Clinical examination, imaging of central nervous and gastrointestinal system, and EEG were performed. Genetic studies include sequencing and deletion/duplication analysis of NPC1 and NPC2 genes. All patients presented with cognitive impairment, ataxia, and supranuclear vertical gaze palsy; one case had gelastic cataplexy. Also they developed epilepsy and cortical atrophy and two patients had thinning of corpus callosum. The 3 patients were compound heterozygotes for NPC1 sequence variants, including 5 missense and 1 nonsense mutations: p.P1007A and p.F1087L in Case 1; p.Q921P and p.G992R in Case 2; and p.R348∗ and p.V1165M in case 3. Mexican patients with juvenile NPC presented with a variable clinical phenotype and compound heterozygosity. This suggests a relative high frequency of mutation carriers as it is reported for European population. Consequently, clinicians should consider NPC as a diagnosis possibility in any adolescent or young adult patient with juvenile dementia and/or ataxia, even in absence of gelastic cataplexy and supranuclear vertical gaze palsy.

[Genetic variants associated to male infertility in Mexican patients]. / Variantes genéticas asociadas con infertilidad masculina en pacientes mexicanos.

Recently Mexican Federation of Obstetrics and Gynecology Colleges (Federación Mexicana de Colegios de Obstetricia y Ginecologia, FEMECOG) published the Mexican guideline forthe management of male infertility, which suggests performing genetic laboratory tests as part of diagnosis and management of infertile patients and states that these should receive genetic counseling. This paper reviews the genetic approach proposed by Mexican guideline. A systematic review of medical literature was performed in Pubmed and Web of Knowledge from 1980 to 2012 in order to find reports of genetic variants associated to male infertility in Mexican patients. Also it is discussed the current knowledge of these variants, their clinical implications and finally the guidelines and recommendations for their molecular diagnosis. Most genetic variants in Mexican infertile patients are chromosome abnormalities. In relation to other variants there is only a report of Y chromosome microdeletions, repeated CAG in androgen receptor and more common mutations in CFTR, and other article reporting mutations in CFTR in patients with congenital absence of vas deferens. Little is known about the genetics of Mexican infertile patients apart from chromosome abnormalities. However, the contribution of genetics as etiology of male infertility is taking more relevance and currently the consensual management of infertile male should include the screening of genetic background. This review pretends to be a quick guide for clinicians who want to know about reports of genetic variants related to male infertility in Mexican population and how to approach their diagnosis.

Mucopolysaccharidosis type II in a female carrying a heterozygous stop mutation of the iduronate-2-sulfatase gene and showing a skewed X chromosome inactivation.

We report a Mexican girl showing the full blown clinical picture of mucopolysaccharidosis type II (MPSII). Iduronate-2-sulfatase (IDS) activity was low and she carried a heterozygous de novo c.1327C>T transition in exon 9, that changes codon 443 for a premature stop (TGA; p.Arg443(*)). Analysis of X-chromosome inactivation in androgen receptor (AR) locus showed a highly skewed ratio of 92:8 suggesting a functional hemizygosity with dominant expression of the mutant IDS and explaining the disease manifestation. This is one of the rare cases of females affected by MPSII due to the combined effect of a skewed X-chromosome inactivation and a de novo IDS mutation. We recommend that clinicians should consider the diagnosis of MPSII even in a girl without positive family history for this condition.