The association between prenatal exposure to organochlorine compounds and neonatal thyroid hormone levels: a systematic review.

In this systematic review, the association between prenatal exposure to organochlorine pesticides (OCPs) and neonatal thyroid hormone levels was studied. A systematic search of scientific literature was performed from the PubMed, SCOPUS and ISI web of science electronic bibliographic databases. The search strategy for the review was [(organochlorine OR "organochlorine pesticides" OR "organochlorine pollutants" OR "organochlorine pollutant") AND ("thyroid hormone" OR triiodothyronine OR Thyroxine OR "fetal thyroid function" OR "thyroid function" OR "Thyroid Stimulating Hormone" AND "prenatal" AND "maternal exposure")] in English sources. In this review, 305 papers (PubMed: 30; Scopus: 29; ISI: 246) were identified through an electronic database search. Twenty-seven articles were assessed for eligibility, from which 16 qualified articles were selected for the final evaluation. The most common OCP metabolites which were evaluated in order were hexachlorobenzene (HCB) (13 studies), pp-dichlorodiphenyldichloroethylene (pp-DDE) (13 studies), hexachlorocyclohexane (HCH) (10 studies) and dichlorodiphenyltrichlorethane (DDT) (eight studies). A review of the documents related to the association of prenatal exposure of OCPs with fetal or neonatal thyroid function tests provides us with heterogeneous data in this field. Factors such as differences in the studied populations and their area, ethnic and genetic background, time and rate of exposure, possible interaction of other thyroid-disrupting environmental factors and dietary intake of micronutrients such as iodine and/or selenium are considered the main limitations for making an accurate conclusion. For some OCPs including DDT, DDE, HCH and HCB, there are supporting evidences, and it is suggested that their exposure could potentially alter the fetal thyroid function and consequently impair the neurodevelopment process of the infants.

SOFT Syndrome: The First Case in Iran.

Primordial dwarfism (PD) is a group of rare genetically heterogeneous disorders consisted of disorders with intrauterine growth retardation continued through the life. SOFT syndrome with characteristics of short stature, onychodysplasia, facial dysmorphism, and hypotrichosis has been presented as a subtype of PD. Only 20 cases of SOFT syndrome have been reported in world to date, but none of them were not in Iran. Our case was 6.5-year-old girl with a complaint of growth retardation including height of 97 cm (Z = -4.6 standard deviation [SD]) and weight of 14 kg (Z = -4 SD) referred to growth clinic. She had a prominent forehead, triangular face, short limbs, malformed nails, and crowded teeth and her psychomotor function was normal. Laboratory and karyotype tests were normal while she was homozygous for c.G491A mutation of POC1A gene thus SOFT syndrome diagnosis was confirmed for her and recombinant growth hormone therapy was discontinued.