Background: The intellectual outcome in children with congenital hypothyroidism detected by neonatal screening is generally good; however, subtle neurological dysfunctions, subnormal IQ, or both, have been reported. Objective: To evaluate the intellectual outcome in 12-year-old patients with congenital hypothyroidism, detected by neonatal screening, in an attempt to identify factors that may affect intellectual development. Methods: The intelligence quotient (IQ) of 40 children with congenital hypothyroidism was evaluated at 12 years of age, using the Wechsler Intelligence Scale for Children -Revised, and compared with the IQ of 40 healthy siblings (control group). Results: The mean IQ score (88.4 Ϯ 13.1) was not significantly different from that of the control group (93.4 Ϯ 10.7). Thirteen patients showed subnormal IQ score (72.4 Ϯ 4.9) compared with their siblings (86.7 Ϯ 9.6; P < 0.0001) and with the other patients (96.1 Ϯ 9.6; P < 0.0001). The low IQ score was associated with lower serum concentrations of thyroxine at diagnosis, poor treatment compliance during follow-up and lower familial IQ. Interviews with parents of children with congenital hypothyroidism revealed that a refusal to acknowledge the disease was linked to poor attention to the child's emotional life and to poor treatment compliance in some cases (11%). Conclusion: Even though the mean IQ score in patients with congenital hypothyroidism falls within normal for the control population, low IQ scores may be present in patients with severe hypothyroidism, inadequate compliance to replacement therapy during follow-up and poor parental pedagogic attitude.
Spondyloepiphyseal dysplasia tarda (SEDT) is an X-linked recessive disorder, characterized by disproportionately short stature and degenerative joint disease, which manifests in the early teens. The gene responsible for SED tarda, SEDL, has been identified in Xp22. We report on three novel SEDL mutations. The first mutation is in the rare, non-canonical 5' splice site of intron 4 (IVS4+4T>C) in an Italian family. Reverse transcription-polymerase chain reaction (RT-PCR) analysis has revealed that this mutation causes alternative splicing of exon 5, and, as a consequence, inclusion of exon 4b sequence. This gives rise to an altered, truncated SEDL protein. We also describe two new deletions: one is a 4-bp deletion in exon 6 [333-336del(GAAT)], identified in a Slovak patient with SEDT, and one is a 1.335-kb deletion (in5/ex6del), found in a Belgian patient. The identification of these novel mutations in SEDL adds to the spectrum of 30 mutations previously identified. A short summary of all currently known SEDL gene mutations is presented.
Pseudohypoparathyroidism type Ia (PHP-Ia) is characterized by Albright's hereditary osteodistrophy (AHO) and resistance to hormones that act via the alpha subunit of the Gs protein (Gsalpha) protein, ie PTH, TSH, FSH/LH, and, as recently described in limited series, GHRH. However, the current lack of data on GHRH secretion, obesity and short stature included in the AHO phenotype hampers interpretation of GH secretory status and its effects on these subjects. We evaluated GH secretion after GHRH plus arginine (Arg) stimulus, IGF-I levels and anthropometric features in an exclusively pediatric population of 10 PHP-Ia subjects. Of our PHP-Ia children, 5 out of 10 (50%) showed impaired GH responsiveness to the provocative test, with a lower prevalence than the 75-100% previously reported. A negative correlation (p=0.024) was found between GH secretion and body mass index (BMI), whereas no correlation emerged between GH and IGF-I values (p=0.948). Height and growth velocity did not significantly differ between GH-deficient and GH-sufficient subjects. In the 5 GH-deficient patients, GHRH resistance could arguably be responsible for hormonal impairment; however, 3 of them were obese, showing normal stature and IGF-I levels: the increased BMI in these subjects could influence GH secretion and its effects. In conclusion, GH deficiency is frequent among PHP-Ia children and its prevalence is variable, two factors indicating that GH secretory testing should be part of the routine management of this patient group. It could be argued that GHRH resistance is the pathogenetic mechanism in most patients, but further studies on GHRH secretion are needed to define which values can be considered as raised. Lastly, because BMI has been indicated as a major determinant of evoked adult GH response to provocative testing, GH levels related to increased BMI also in childhood could be helpful in defining GH assessment in obese or overweight PHP-Ia children.
Noonan-like syndrome with loose anagen hair (NS/LAH; OMIM 607721), recently related to the invariant c.4A>G missense change in SHOC2, is characterized by features reminiscent of Noonan syndrome. Ectodermal involvement, short stature associated with growth hormone (GH) deficiency (GHD), and cognitive deficits are common features. We report on a patient with molecularly confirmed NS/LAH exhibiting severe short stature associated with GH insensitivity (GHI), and chronic complex tics, a neurological feature never described before in this syndrome. IGF1 generation test revealed only a blunted increase in IGF1 after exogenous GH treatment, revealing mild GH insensitivity associated with proper STAT5 activation. Most common causes of secondary tics in childhood were excluded.
The influence of the initial L-T4 dose and some other factors on the intellectual development was evaluated at 7 years of age in 47 congenitally hypothyroid children detected by the regional screening program. All patients were initially treated with 25 micrograms LT4/kg/day that represented a mean replacement dose of 6.8 +/- 1.3 micrograms/kg. Despite the "low" initial dose mean IQ at 7 years resulted within normal range (96 +/- 9). Twenty-eight patients initially treated with 6.0 +/- 0.6 micrograms L-T4/kg/day had a mean IQ (96 +/- 9) which was not different with respect to 19 patients (IQ 94 +/- 7) treated with a significantly higher L-T4 dose (8.1 +/- 0.9 micrograms/kg/day; p < 0.0001). The initial L-T4, dose did not correlate with IQ at 7 years whereas a significant correlation was found between IQ and serum T4 concentration at diagnosis (r = 0.35; p < 0.01) regardless of the fact that serum T4 concentration normalized after the first 2 months of therapy in both groups. Twenty-three patients whose serum T4 at diagnosis was < 2 micrograms/dl (1.0 +/- 0.5) had a mean IQ at 7 years (92 +/- 9) which was significantly lower than the 24 patients (IQ 98 +/- 7; p < 0.02) whose serum T4 was > 2 micrograms/dl (5.7 +/- 2.4; p < 0.001). The present findings suggest that the severity of neonatal hypothyroidism is an important factor in determining subsequent intellectual development of congenitally hypothyroid children.
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