Sex dimorphism of weight and length at birth: evidence based on disorders of sex development.

BACKGROUND: Males have higher weight and length at birth than females. AIM: To verify the influence of the Y chromosome and the action of intrauterine androgens on weight and length at birth of children with Disorders of Sex Development (DSD). SUBJECTS AND METHODS: A cross-sectional and retrospective study. Patients with Turner syndrome (TS), complete (XX and XY), mixed (45,X/46,XY) and partial (XY) gonadal dysgenesis (GD), complete (CAIS) and partial (PAIS) androgen insensitivity syndromes and XX and XY congenital adrenal hyperplasia (CAH) were included. Weight and length at birth were evaluated. RESULTS: Weight and length at birth were lower in TS and mixed GD when compared to XY and XX DSD cases. In turn, patients with increased androgen action (117 cases) had higher weight and length at birth when compared to those with absent (108 cases) and decreased (68 cases) production/action. In birthweight, there was a negative influence of the 45,X/46,XY karyotype and a positive influence of increased androgen and gestational age. In birth length, there was a negative influence of the 45,X and 45,X/46,XY karyotypes and also a positive influence of increased androgen and gestational age. CONCLUSIONS: The sex dimorphism of weight and length at birth could possibly be influenced by intrauterine androgenic action.

Two Novel Mutations in the Thyroid Hormone Receptor ß in Patients with Resistance to Thyroid Hormone (RTH ß): Clinical, Biochemical, and Molecular Data.

The syndrome of resistance to thyroid hormone (RTH ß) is an inherited disorder characterized by variable tissue hyposensitivity to 3,5,30-L-triiodothyronine (T(3)), with persistent elevation of free-circulating T(3) (FT(3)) and free thyroxine (FT(4)) levels in association with nonsuppressed serum thyrotropin (TSH). Clinical presentation is variable and the molecular analysis of THRB gene provides a short cut diagnosis. Here, we describe 2 cases in which RTH ß was suspected on the basis of laboratory findings. The diagnosis was confirmed by direct THRB sequencing that revealed 2 novel mutations: the heterozygous p.Ala317Ser in subject 1 and the heterozygous p.Arg438Pro in subject 2. Both mutations were shown to be deleterious by SIFT, PolyPhen, and Align GV-GD predictive methods.