Pharmacogenetics of CYP2D6 and tamoxifen therapy: Light at the end of the tunnel?

The clinical usefulness of assessing the enzymatic activity of CYPD6 in patients taking tamoxifen had been longly debated. In favour of preemptive evaluation of phenotypic profile of patients is the strong pharmacologic rationale, being that the formation of endoxifen, the major and clinically most important metabolite of tamoxifen, is largely dependent on the activity of CYP2D6. This enzyme is highly polymorphic for which the activity is largely depending on genetics, but that can also be inhibited by a number of drugs, i.e. antidepressants, which are frequently used in patients with cancer. Unfortunately, the clinical trials that have been published in the last years are contradicting each other on the association between CYP2D6 and significant clinical endpoints, and for this reason CYP2D6 genotyping is at present not generally recommended. Despite this, the CYP2D6 genotyping test for tamoxifen is available in many laboratories and it may still be an appropriate test to use it in specific cases.

Thyroid-stimulating hormone levels in the first days of life and perinatal factors associated with sub-optimal neuromotor outcome in pre-term infants.

AIM: To identify perinatal factors associated with sub-optimal neuromotor outcome in infants without evident central nervous system lesions (intraventricular hemorrhage/ periventricular leukomalacia), with gestational age ≤30 (group I) and of 31-32 weeks (group II). PATIENTS AND METHODS: A total of 102 premature infants admitted to the Neonatal Intensive Care Unit of Pisa, at 26-32 weeks of gestation, were studied. Data about perinatal factors and TSH values at 3-4 days of life were collected. The assessment of neuromotor development was performed at 18 months of corrected age, using the locomotor subscale of the Griffiths Scales of Mental Development. RESULTS: Risk factors supposed to be predictive of sub-optimal neuromotor outcome (odds ratio >1) were at ≤30 weeks: male sex, small for gestational age, patent duct arterious, respiratory distress syndrome, and at 31-32 weeks: Apgar at 5 min <7, respiratory distress syndrome, patent duct arterious and birth weight <1500 g. A strong correlation was also found between TSH screening values >4,3 mU/l and suboptimal neuromotor outcome in both groups. CONCLUSIONS: Several perinatal factors, acting on an immature and more vulnerable nervous system, such as the pre-term one, different for different gestational ages, are associated with a sub-optimal neuromotor outcome. Higher, but within the normal range, TSH values at screening seem to be a strong risk factor for neuromotor outcome in preterm infants without intraventricular hemorrhage or periventricular leukomalacia.

Neonatal outcome in newborns from mothers with endocrinopathies.

INTRODUCTION: Hypothyroidism and gestational diabetes are common endocrine disorders in pregnancy. Our aim is to evaluate the outcome of newborns from mothers with hypothyroidism and from mothers with gestational diabetes. PATIENTS AND METHODS: The study analysed 216 newborns: 112 from mothers with gestational diabetes and 104 from mothers with hypothyroidism. For each case, we included as a control a newborn of same sex and gestational age from a mother without diabetes or thyreopathy. RESULTS: In newborns from mothers with gestational diabetes there was an increased frequency of hypoglycaemia and hypocalcaemia, of lower head circumference and of small-for-gestational age (SGA) birth or macrosomy (LGA) than controls. The newborns from mothers with hypothyroidism are more frequently SGA or LGA and they have a slightly increased risk of hypoglycaemia. CONCLUSIONS: Newborns from mothers with diabetes mellitus or hypothyroidism have an increased risk of being SGA or LGA, and to develop a mild transient hypoglycaemia. Newborns from mothers with diabetes mellitus have also an increased risk to develop hypocalcaemia and to have a lower head circumference than controls. Thus, to prevent SGA or LGA births, it is very important an early diagnosis and treatment, and a strict metabolic control of these conditions.