Phosphodiesterase 8B gene variants are associated with serum TSH levels and thyroid function.

Thyroid-stimulating hormone (TSH) controls thyroid growth and hormone secretion through binding to its G protein-coupled receptor (TSHR) and production of cyclic AMP (cAMP). Serum TSH is a sensitive indicator of thyroid function, and overt abnormalities in thyroid function lead to common endocrine disorders affecting approximately 10% of individuals over a life span. By genotyping 362,129 SNPs in 4,300 Sardinians, we identified a strong association (p = 1.3 x 10(-11)) between alleles of rs4704397 and circulating TSH levels; each additional copy of the minor A allele was associated with an increase of 0.13 muIU/ml in TSH. The single-nucleotide polymorphism (SNP) is located in intron 1 of PDE8B, encoding a high-affinity cAMP-specific phosphodiesterase. The association was replicated in 4,158 individuals, including additional Sardinians and two genetically distant cohorts from Tuscany and the Old Order Amish (overall p value = 1.9 x 10(-20)). In addition to association of TSH levels with SNPs in PDE8B, our genome scan provided evidence for association with PDE10A and several biologically interesting candidates in a focused analysis of 24 genes. In particular, we found evidence for association of TSH levels with SNPs in the THRB (rs1505287, p = 7.3 x 10(-5)), GNAQ (rs10512065, p = 2.0 x 10(-4)), TG (rs2252696, p = 2.2 x 10(-3)), POU1F1 (rs1976324, p = 3.9 x 10(-3)), PDE4D (rs27178, p = 8.3 x 10(-3)), and TSHR (rs4903957, p = 8.6 x 10(-3)) loci. Overall, the results suggest a primary effect of PDE8B variants on cAMP levels in the thyroid. This would affect production of T4 and T3 and feedback to alter TSH release by the pituitary. PDE8B may thus provide a candidate target for the treatment of thyroid dysfunction.

First case reported of Turner syndrome and trisomy 14 chromosomal mosaicism in a patient.

A 25-year-old woman with a mosaic 45,X/47XX,+14 karyotype is reported. She presented with short stature, short downward slanting palpebral fissures, broad nasal bridge, mouth with downturned corners, short and wide neck, swirly hyperpigmentation of the skin, and body asymmetry secondary to right hemihyperplasia. As there was an admixture of 45,X and trisomy 14, it was not possible to determine the cell line that had the greatest influence on the phenotype. We postulate that the proposita's survival until the third decade was owing to the chromosomal complementation of both aneuploidy cell lines. To our knowledge, this chromosomal association has not been previously reported.

GATA2 null mutation associated with incomplete penetrance in a family with Emberger syndrome.

INTRODUCTION: GATA2 mutations are associated with several conditions, including Emberger syndrome which is the association of primary lymphedema with hematological anomalies and an increased risk for myelodysplasia and leukemia. OBJECTIVE: To describe a family with Emberger syndrome with incomplete penetrance. METHODS: A DNA sequencing of GATA2 gene was performed in the parents and offspring (five individuals in total). RESULTS: The family consisted of 5 individuals with a GATA2 null mutation (c.130G>T, p.Glu44*); three of them were affected (two of which were deceased) while two remained unaffected at the age of 40 and 13 years old. The three affected siblings (two boys and one girl) presented with lymphedema of the lower limbs, recurrent warts, epistaxis and recurrent infections. Two died due to hematological abnormalities (AML and pancytopenia). In contrast, the two other family members who carry the same mutation (the mother and one brother) have not presented any symptoms and their blood tests remain normal. DISCUSSION: Incomplete penetrance may indicate that GATA2 haploinsufficiency is not enough to produce the phenotype of Emberger syndrome. It could be useful to perform whole exome or genome sequencing, in cases where incomplete penetrance or high variable expressivity is described, in order to probably identify specific gene interactions that drastically modify the phenotype. In addition, skewed gene expression by an epigenetic mechanism of gene regulation should also be considered.

Ambiguous genitalia by 9p deletion inherent to a dic(Y;9)(q12;p24).

We describe here a 3-month-old male infant with brachy-plagyocephaly, short neck, widely spaced nipples, mild hypertonia, and ambiguous external genitalia but with both testes in the scrotum and no Müllerian derivates. His karyotype was 45,X,der(Y;9)(q12;p24).ish der(Y;9)(DYZ3+,SRY+,9ptel-) de novo. This patient's impaired sex differentiation is consistent with gonadal dysgenesis and compares with the male-to-female sex reversal secondary to a partial 9p deletion in spite of an intact Yp or SRY locus documented in 24 patients including a sex-reversed girl with a (Y;9) dicentric derivative. As for the cytogenetic findings, this case represents the second instance of a de novo pseudodicentric (Y;9) chromosome with loss of both distal 9p and Yq12 regions, apparent intactness of SRY, and consistent or preferential inactivation of the Y centromere. In addition, the possible 9p23p-p22 duplication observed in this case evokes the concomitant 9p22-p21 duplication documented in the previous girl with a (Y;9) derivative. Hence, these striking similarities point to a nonrandom Y;9 rearrangement in patients with either sex reversal or gonadal dysgenesis. Even if the present pseudodicentric derivative had inactivated the Y centromere, the existence of some variant cells points to functional dicentricity as it has been documented in other Y;autosome dicentric derivatives.

Association between the Xba I polymorphism of APOB gene and plasma lipid level in Mexican patients with coronary artery disease.

Some studies, that consider polymorphisms of the apolipoprotein B (APOB) gene as risk factors for coronary artery disease (CAD), have reported discordant results. The aim of the present study was to search for associations between plasma lipid profiles with the DNA Xba I polymorphism of the APOB gene in CAD patients diagnosed by angiography (CAD+). In the present study we compared 114 Mexican patients (80 men and 34 women) with CAD+ and 132 control patients (59 men and 73 women) without evidence of ischemia or arterial damage (CAD-). The frequency of X+/X+ genotype of Xba I polymorphism, in CAD+ group, was 23% (26/114) compared with 8% (11/132) in the CAD- (OR 3.25, p = 0.002). The patients with X+/X+ for the Xba I genotype APOB gene had higher concentration of triglycerides (TG) and VLDL in plasma than CAD- (p< 0.05). The genotype X+/X+ in the CAD had an effect increasing the TG and VLDL plasma levels when compared with individuals with X-/X- and X-/X+ genotypes. The present study indicated that the X+X+ genotype of Xba I polymorphism is associated with CAD+ patients and high plasma levels of TG and VLDL, in the Mexican population.