Relative predispositional effects of HLA class II DRB1-DQB1 haplotypes and genotypes on type 1 diabetes: a meta-analysis.

The direct involvement of the human leukocyte antigen class II DR-DQ genes in type 1 diabetes (T1D) is well established, and these genes display a complex hierarchy of risk effects at the genotype and haplotype levels. We investigated, using data from 38 studies, whether the DR-DQ haplotypes and genotypes show the same relative predispositional effects across populations and ethnic groups. Significant differences in risk within a population were considered, as well as comparisons across populations using the patient/control (P/C) ratio. Within a population, the ratio of the P/C ratios for two different genotypes or haplotypes is a function only of the absolute penetrance values, allowing ranking of risk effects. Categories of consistent predisposing, intermediate ('neutral'), and protective haplotypes were identified and found to correlate with disease prevalence and the marked ethnic differences in DRB1-DQB1 frequencies. Specific effects were identified, for example for predisposing haplotypes, there was a statistically significant and consistent hierarchy for DR4 DQB1*0302s: DRB1*0405 =*0401 =*0402 > *0404 > *0403, with DRB1*0301 DQB1*0200 (DR3) being significantly less predisposing than DRB1*0402 and more than DRB1*0404. The predisposing DRB1*0401 DQB1*0302 haplotype was relatively increased compared with the protective haplotype DRB1*0401 DQB1*0301 in heterozygotes with DR3 compared with heterozygotes with DRB1*0101 DQB1*0501 (DR1). Our results show that meta-analyses and use of the P/C ratio and rankings thereof can be valuable in determining T1D risk factors at the haplotype and amino acid residue levels.

Response to growth hormone with respect to pubertal status on increased dose in idiopathic growth hormone deficiency: an analysis of Turkish children in the KIGS database (Pfizer International Growth Study).

AIM: To compare the growth response to growth hormone (GH) treatment in patients with idiopathic GH deficiency (IGHD) who were prepubertal with the response of those who were pubertal at the onset of GH therapy on an increased GH dose. PATIENTS AND METHODS: Among the Turkish patients enrolled in the Pfizer International Growth Study (KIGS) database with the diagnosis of IGHD, the growth data over 2 years of GH therapy were analyzed longitudinally of 113 (79 M) prepubertal (Group 1) and 44 (33 M) pubertal (Group 2) patients. Pubertal signs were reported to be present initially or to have appeared within 6 months of GH therapy in Group 2. Mean +/- SD age at onset of therapy was 8.7 +/- 3.5 and 13.5 +/- 1.8 years; height SDS -4.2 +/- 1.4 and -3.2 +/- 1.1 (p < 0.05) in Groups 1 and 2, respectively. Mid-parental height (MPH) SDS did not show a significant difference between the two groups (-1.5 +/- 1.1 vs -1.7 +/- 1.1). RESULTS: Delta height SDS over 2 years of therapy was significantly higher in Group 1 (1.1 +/- 1.0) than in Group 2 (0.7 +/- 0.6) (p <0.05) in spite of a significantly lower dose of GH (14.6 +/- 3.3 in Group 1 vs 17.0 +/- 3.1 IU/m2/week in Group 2, p < 0.05). Ht--MPH SDS showed an increase from -2.4 +/- 1.7 to -1.4 +/- 1.5 in Group 1 and from -1.5 +/- 1.5 to -0.8 +/- 1.3 in Group 2. Overall delta height SDS showed negative correlations with age (r = -0.32), height SDS (r = -0.41) and height--MPH SDS (r = -0.40) at onset of therapy (p < 0.001). CONCLUSIONS: These data show that in IGHD the slight increase (15-20%) in the dose of GH during puberty was not adequate to maintain height velocity at the same magnitude as in prepuberty, and thus was not cost effective.

A novel semiquantitative polymerase chain reaction/enzyme digestion-based method for detection of large scale deletions/conversions of the CYP21 gene and mutation screening in Turkish families with 21-hydroxylase deficiency.

21-Hydroxylase deficiency is a recessively inherited disorder resulting from mutations in the CYP21 gene. The CYP21 gene is located along with the CYP21P pseudogene in the human leukocyte antigen major histocompatibility complex region on chromosome 6. Molecular diagnosis is difficult due to the 98% similarity of CYP21 and CYP21P genes and the fact that almost all frequently reported mutations reside on the pseudogene. Allele-specific PCR for the 8 most frequently reported point mutations was performed in 31 Turkish families with at least a single 21-hydroxylase-deficient individual. The allele frequencies of the point mutations were as follows: P30L, 0%; IVS2 (AS,A/C-G,-13), 22.5%; G110delta8nt, 3.2%; I172N, 11.4%; exon 6 cluster (I236N, V237E, M239K), 3.2%; V281L, 0%; Q318X, 8%; and R356W, 9.6%. Large deletions and gene conversions were detected by Southern blot analysis, and the allele frequencies were 9.6% and 22.5%, respectively. Sequence analysis of the gene, performed on patients with only 1 mutated allele, revealed 2 missense mutations (R339H and P435S). A novel semiquantitative PCR/enzyme digestion-based method for the detection of large scale deletions/conversions of the gene was developed for routine diagnostic purposes, and its accuracy was shown by comparison with the results of Southern blot analysis.

The effect of growth hormone treatment on biochemical indices in hypophosphatemic rickets.

BACKGROUND: Growth hormone (GH) in combination with conventional therapy in hypophosphatemic rickets (HR) has been shown to promote renal phosphate (P) conservation and to result in a better metabolic control. This study aimed at investigating the acute biochemical effects of GH in 7 patients (5 female, 2 male) with HR aged between 2.16 and 16 years. METHODS: Each patient received the following in a sequential design: oral P plus 1,25-dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)] therapy to determine the optimum doses for baseline requirement followed by GH-only therapy and GH +1,25-(OH)(2)D(3) therapy and GH + P +1,25-(OH)(2)D(3) therapy each for 2 weeks with 1 washout week off treatment in between. GH was given at a dose of 0.03 mg/kg/day s.c. on a daily basis. The dose of oral P used ranged between 500 and 2,000 mg/day, and the dose of 1,25-(OH)(2)D(3) ranged between 0.25 and 0.5 microg/day and was kept constant for each child throughout the study. RESULTS: Laboratory investigations repeated at the end of each treatment, and the first washout period showed that the serum P level was highest (2.9 ng/ml) during the GH + P + 1,25-(OH)(2)D(3) period with higher serum 1,25-(OH)(2)D(3) levels: 50.9 +/- (SD) 23.4 ng/l. Parathyroid hormone and alkaline phosphatase levels did not show a significant difference between the periods. The tubular P reabsorption rate showed an insignificant increase during GH therapy periods. CONCLUSION: Considering the fixed dose of P and calcitriol, it may be concluded that GH added to conventional treatment in HR resulted in a slight improvement in the biochemical parameters without any side effects at the short term.

Growth hormone treatment in short children with intrauterine growth retardation.

The aim of this prospective controlled study was to assess the effect of rhGH in short prepubertal children with intrauterine growth retardation and normal growth hormone status. Twenty-six children were randomized into treatment (12F, 4M) and control (6F, 4M) groups. Mean ages were 5.3 (1.3) yr and 4.3 (1.7) yr, respectively. rhGH (Genotropin) was used at a dose of 0.2 IU/kg/day as daily s.c. injections for two years. In the treated group, mean height SDS increased from -3.0 (0.5) to -1.9 (0.7) and height velocity SDS showed a significant increase from -1.3 (2.0) to 3.7 (1.8) in the first year (p < 0.001) and 1.6 (1.8) (p < 0.01) in the second year of treatment. In the controls, height SDS, initially -2.7 (1.4), and height velocity SDS, initially -0.9 (1.1), remained essentially the same during two years of follow-up. Height SDS for bone age changed by 0.6 in the treated group and 0.4 in the control group. Target height SDS--initial height SDS in the treated group improved by 1.1 SD but declined in the control group. IGF-I levels increased from 9.5 (4.2) nmol/l (72 [31.8] ng/ml) to 32.5 (27.0) nmol/l (244.4 [202.8] ng/ml) (p = 0.004) in the treated group while no change was observed in the controls. No adverse effects were encountered during rhGH therapy. It was concluded that rhGH treatment induces a significant increase in growth velocity in the short term. This outcome, as opposed to the unchanged indices in the control group over the same period, may be indicative of an improved height prognosis in short children born with intrauterine growth retardation treated with rhGH.

Glucocorticoid receptors in patients with congenital adrenal hyperplasia.

To determine the glucocorticoid receptor (GC-R) status in congenital adrenal hyperplasia (CAH) we examined 11 patients (5 female, 6 male) with 21-hydroxylase deficiency and 3 patients (2 female, 1 male) with 11beta-hydroxylase deficiency. The mean age at investigation was 8.9+/-3.5 yr. Age of diagnosis was 4.4+/-3.2 yr and all patients were being treated with hydrocortisone. The control group included 10 (5 female, 5 male) age-matched healthy children. Blood samples were drawn at 0800 a.m. after an overnight fast in all subjects and after 5 days off treatment in patients with CAH. Serum cortisol (in all children), and serum 17-hydroxyprogesterone and androstenedione (in the patient group) were measured by radioimmunoassay. Mononuclear leukocytes were isolated from peripheral blood and the binding of [3H]dexamethasone to GC-R was examined. GC-R number and the dissociation constant (Kd), which is inversely proportional to its binding affinity, were determined. Mean GC-R numbers were 5814+/-1574 and 6816+/-1647; mean Kd values were 3.6+/-1.5 nM and 4.2+/-0.7 nM in patient and control groups, respectively. There were no significant differences in these parameters between the two groups. Neither receptor number nor binding affinity correlated with basal serum cortisol levels in either group. In the patient group, no correlation was observed between replacement hydrocortisone doses and either morning serum cortisol levels or GC-R number. The higher binding affinity and requirement of higher hydrocortisone dose might have been due to a compensatory response to increased clearance of glucocorticoids. In conclusion, GC-R parameters are not changed in patients with CAH and the variability of glucocorticoid replacement doses may be related to other functional defects of GC-R and glucocorticoid pharmacokinetics.

Frequency of renal malformations in Turner syndrome: analysis of 82 Turkish children.

We evaluated the frequency of renal malformations in relation to nonmosaic 45,X (group A, 45 patients, 54.9%) and mosaic/structural abnormalities of X (group B, 37 patients, 45.1%) in 82 Turkish patients with Turner syndrome (TS). Ultrasonography of the kidneys and collecting system was performed in all patients. Of the 82 patients, 31 had different renal malformations (37.8%). Horse-shoe kidney was observed in 9 (29.0%) of the 31 patients, and 17 patients (54.8%) had various collecting system malformations, while 5 (16.2%) had malrotation and other positional abnormalities. The prevalence of renal malformations was significantly higher in group A (51.1%) than group B (21.6%) (2:7.94, P<0.05). Although 8 of the 9 patients with horse-shoe kidney had the 45,X karyotype, collecting system malformations were observed more frequently in group B. Recurrent urinary tract infections (UTIs) were detected during follow-up in 7 patients, and hypertension developed in 3 patients. In patients who had a normal baseline nephrological evaluation, no problem suggesting renal disease developed during follow-up. We conclude that all forms of TS should have routine nephrological screening on diagnosis, since structural malformations of the kidney occur more frequently in nonmosaic 45,X TS, while collecting system malformations are mostly seen in mosaic/structural X forms. Those included in the group for nephrological follow-up had an increased risk for hypertension and/or UTI.

Bilateral ovarian steroid cell tumor in congenital adrenal hyperplasia due to classic 11beta-hydroxylase deficiency.

An 8.7 year-old patient, raised as a boy, presented with premature appearance of pubic hair and accelerated growth since 2 years of age and ambiguous genitalia noted at birth. There was first degree consanguinity between his parents. A similar problem was reported in a cousin. Examination of the external genitalia revealed complete scrotal fusion, a 5 cm long phallus, urogenital sinus at base of phallus with no gonads palpable. Pigmentation was increased. His blood pressure was 150/100 mm Hg. Pubic and axillary hair were at stage 3. Bone age was 17 years. Adrenal ultrasound was normal. Pelvic ultrasound showed relatively enlarged uterus and ovaries with normal echogenicity. Karyotype was 46,XX. Hormone profile was compatible with congenital adrenal hyperplasia (CAH) due to 11beta-hydroxylase deficiency (11-deoxycortisol: 11.5 nmol/l [400 ng/dl] [normal: 0.6-4.5 nmol/l [20-155 ng/ml]], androstenedione: 17.4 nmol/l [5 ng/ml] [normal: 0.1-1.2 nmol/l [0.03-0.35 ng/ml]]). Prednisolone and antihypertensive drugs were started. The patient underwent bilateral salpingo-oophorectomy and hysterectomy at 9.1 years. Histopathological examination of both ovaries revealed steroid cell tumor. The type of the tumor was "not otherwise specified" (NOS). Basal hormone levels and ACTH test performed 10 months after the operation and 7 days off treatment reconfirmed the diagnosis of 11beta-hydroxylase deficiency. Steroid cell tumors are extremely rare forms of steroid hormone-reducing ovarian neoplasms in childhood and may coexist with or imitate virilizing CAH.

A comparison of the use of premixed insulins in pen-injectors with conventional patient-mixed insulin treatment in children and adolescents with IDDM. Is there a decreased risk of night hypoglycemia?

Insulin injection is a problem in pediatric and adolescent age, and premixed insulin therapy given in pen-injectors (Novopen II) is expected to increase compliance. Compliance with treatment and safety of this kind of insulin substitution was investigated in 20 IDDM patients (8.2-19.6 years old). The study was of randomized cross-over design and its duration was 6 (2x3) months. Metabolic parameters were compared between premixed insulin therapy via pen-injector and patient-mixed insulin therapy via conventional syringe, and no differences were observed except for the postponing of night hypoglycemic attacks to 07.00 a.m. during premixed insulin therapy. No technical or medical problems occurred. Patients were more satisfied with the new therapy regimen as determined by questionnaire. We concluded that this kind of insulin substitution is safe in pediatric and adolescent IDDM patients.

HLA-DR and -DQ associations with insulin-dependent diabetes mellitus in a population of Turkey.

Genetic susceptibility to insulin-dependent diabetes mellitus (IDDM) has been shown to be associated with MHC in many studies. To extend this data with a population with relatively low IDDM incidence, MHC DRB, DQA, and DQB have been investigated by polymerase chain reaction and sequence specific oligonucleotide probe hybridization (PCR/SSO) in 178 IDDM patients from Turkey and compared to 248 healthy controls. Significant differences are detected between IDDM and control groups in the frequencies of DRB1*0402 DQA1*03 DQB1*0302 (28.1% vs. 5.2%, p < 0.0001, OR: 7.1) and DRB1*0301 DQA1*0501 DQB1*02 (57% vs. 18.1%, p < 0.0001, OR: 6.1). Among the negative associations, the most strong ones are with DRB1*1401 DQA1*0101 DQB1*0503 (0.6% vs. 8.9%, p < 0.0001, OR: 0.1), DRB1*1502 DQA1*0103 DQB1*0601 (1.1% vs. 7.7%, p = 0.0023, OR: 0.1), DRB1*1301 DQA1*0103 DQB1*0603 (0.6% vs. 6.9%, p = 0.0039, OR: 0.2) and DRB1*1101 DQA1*0501 DQB1*0301 (3.9% vs. 12.1%, p < 0.0001, OR: 0.2). When the DRB, DQA or DQB genotypes of the susceptible alleles are compared, the most strong susceptibility marker of the disease is found to be DRB1*0301/*04 (31.4% vs. 2.8%, p < 0.0001, OR: 15.8) and among these, heterozygote genotype DRB1*0301/*0401 (4.5% vs. 0, p = 0.0008, OR: 24.8). These results confirm the positive associations with IDDM previously observed in other Caucasian populations and reveal many negative and strong associations which maybe underlining several characteristics that distinguish Turkish diabetics form other Caucasians.

Successful therapy with calcium channel blocker (nifedipine) in persistent neonatal hyperinsulinemic hypoglycemia of infancy.

The appropriate management of persistent hyperinsulinemic hypoglycemia of infancy (PHHI) still remains controversial. Some patients show a response to treatment with diazoxide or somatostatin, but a number of children require total or near-total pancreatectomy to control hyperinsulinism. Recent studies suggest a dysfunction in the adenosine triphosphate-sensitive potassium channel present in the plasma membrane of pancreatic beta-cells in PHHI. The closure of these channels initiating the depolarization of the beta-cell membrane and opening of calcium channels results in an increase in intracellular calcium which triggers insulin secretion. A calcium channel blocking agent has been shown to block this process and decrease insulin secretion of the nesidioblastotic beta-cells in vitro and to control the hyperinsulinemic hypoglycemia of the patient in vivo. To examine the efficacy of calcium channel blocker therapy, three patients with PHHI were treated with nifedipine. PHHI was diagnosed by inappropriately high insulin levels for low blood glucose levels at 8-10 days of age. Normoglycemia was maintained by a high dose of glucose infusion at a rate of 14-16 mg/kg/min. Therapy using diazoxide and/or somatostatin analogue failed to restore euglycemia in these three patients. The first patient underwent near-total pancreatectomy; however, hyperinsulinism recurred 30 days after surgery. All patients were started on short acting nifedipine at a dose of 0.3 mg/kg/day per os in four doses. To maintain blood glucose levels in normal ranges, the dose of nifedipine was progressively increased to 0.7-0.8 mg/kg/day. Glucose infusion rate to restore euglycemia decreased and was discontinued on the 4th to 10th day of nifedipine treatment. The patients, who have now been followed on nifedipine therapy for over 12 months, are normoglycemic with normal insulin levels. The growth and neuromotor development of the patients are unremarkable except for mild developmental delay of the patient who underwent near-total pancreatectomy. No side effects were encountered at the doses used. In conclusion, calcium channel blocking agents can be used with efficacy and safety in PHHI to control the hyperinsulinemia.

Deflazacort treatment in progressive diaphyseal dysplasia (Camurati-Engelmann disease).

Progressive diaphyseal dysplasia (PDD), a rare disorder of bones, in recent years has been accepted as a systemic disease within the spectrum of connective tissue disorders associated with immunological abnormalities. Steroids have been used in the treatment of PDD with variable success. In this report PDD is described in a 5-year-old boy who presented with leg pain, fatigue, headache and anorexia with an onset in infancy. Physical examination revealed a waddling gait, thorax deformity and thickening in the upper extremities. The diagnosis was made by radiologic demonstration of cortical thickening and a narrowed medullary cavity of the long bones of extremities. Bone scintigraphy showed areas of increased osteoblastic activity in the diaphyseal part of the long bones of extremities and the skull. Electron microscopic examination revealed myopathic and vascular changes. Serum immunoglobulin A, G and M levels were elevated and CD4 positive T cell numbers were low. Deflazacort, a steroid with a similar anti-inflammatory effect to prednisolone but with fewer adverse effects, was started in a dose of 1.2 mg/kg/day. Deflazacort treatment resulted in clinical and radiological improvement within 12 months with no side effects. In conclusion, steroids may be recommended as an effective method of treatment in PDD and deflazacort may be a safe alternative steroid.

Brachymetacarpia V in familial short stature.

This study was planned to search for the presence of possible tubular bone abnormalities in familial short stature (FSS) as has been previously noted in some reports. Twenty-five (17 male, 8 female) children with FSS aged 10.0 SD 3.6 years were taken as the study group, and 23 (14 male, 9 female) children of normal stature aged 10.6 SD 2.7 years comprised the control group. FSS was defined as height of the child and mean parental height below 3rd centile line, normal growth velocity and bone age within 2 years of chronological age. Other causes of short stature were ruled out. Height, weight, sitting height and arm, forearm and upper arm length measurements were taken by standard methods. A left hand and wrist X-ray was taken to evaluate the length of the 5th metacarpal. Children with FSS had a significantly higher prevalence of brachymetacarpia V (64%) than the children with normal stature (21.7%) (p < 0.001). Other tubular bone parameters, however, were normal. Sitting height/height ratios were in normal ranges and comparable in FSS and the control group. Similarly arm to height and upper arm to forearm ratios were comparable in the two groups excluding disproportionate shortening of the limbs. The finding of increased incidence of brachymetacarpia V in FSS may suggest an underlying tubular bone abnormality, which may explain the short stature in FSS.

Long-term diazoxide treatment in persistent hyperinsulinemic hypoglycemia of infancy: a patient report.

Long-term diazoxide and somatostatin analogue have been used in the treatment of persistent hyperinsulinemic hypoglycemia of infancy albeit with some side effects. We report a case with persistent hyperinsulinemic hypoglycemia who has been on diazoxide therapy for 4.5 years. Diazoxide treatment maintained normoglycemia without causing any side effects, including hypertrichosis.

Spironolactone therapy in hypertrichosis.

Although regarded as a benign condition, simple hypertrichosis may be very disturbing to a child cosmetically. An abnormality in androgen metabolism has been implied in the etiology of simple hypertrichosis recently. This study was undertaken to investigate the effect of spironolactone therapy for its antiandrogenic property in 12 prepubertal girls with hypertrichosis with no underlying etiology. The girls, with a mean age of 6.9 (1.2) years, had normal height and bone age. Basal hormone levels and adrenocorticotropin stimulation test results were in the normal ranges. Pelvic and adrenal ultrasound did not reveal pathology. Total and medullary hair width were measured from hair taken from preauricular, anterior midthigh, distal and proximal forearm areas. Spironolactone was started at an oral dose of 25 and increased to 100 mg x m(-2) x day(-1) twice daily for 1 year. Total hair width decreased significantly in the preauricular and anterior midthigh regions up to 6-9 months of treatment. Medullary hair width, which was affected by therapy to a greater extent, decreased significantly in all regions up to 6 months. Both total and medullary hair width showed a tendency to increase afterwards. No side effects were encountered. Spironolactone may be used in the treatment of simple hypertrichosis; however, more data are needed to clarify the efficacy and safety of anti-androgen therapy in hypertrichosis.

beta-Endorphin and some hormonal levels in children with acute stress hyperglycaemia.

The levels of beta-endorphin, insulin, cortisol, GH, glucagon, prolactin and TSH were measured in serum samples of 9 hyperglycaemic patients (3 female, 6 male) with a mean age of 4.1 years admitted to the pediatric emergency unit. All patients were in acute stress due to severe diseases (acute gastroenteritis, bronchopneumonia, septicaemia, etc.). Initial and repeat blood samples for hormone determination were taken at admission and in the recovery phase (after 4-6 weeks of treatment). OGTT was also performed in the recovery phase. The hyperglycaemia, monitored hourly following the initial determination, returned to normal in all patients in 1-5 h without specific treatment. Mean serum glucose values at admission and in the recovery phase were 287.0 and 84.1 mg/dl. Concomitant to the hyperglycaemia encountered in these patients in the acute phase of stress, an increase was noted in all hormone levels excluding glucagon and cortisol. All elevated hormone levels fell to normal in 4-6 weeks with significant differences from initial levels for beta-endorphin (P < 0.05) and insulin (P < 0.01). OGTT gave a normal curve. These results indicate that stress hyperglycaemia, despite high insulin levels, is associated with an increase in beta-endorphin levels. The results also show that hyperglycaemia in acute disease does not alter OGTT in short-term follow up.

Thyroid ultrasound in IDDM.

Insulin dependent diabetes mellitus (IDMM) is often associated with autoimmune thyroiditis (AIT) and a high prevalence of thyroid antibodies (TA). Ultrasound imaging of the thyroid may contribute to the evaluation of patients with AIT. We therefore investigated ultrasound findings of the thyroid in 83 IDDM patients (44F, 39M) with an age range of 2.3-22.3 yrs (median 11.1). Thyroid volume (ml) determined by ultrasound ranged between 1.3 and 17.9 (median 5.7). Thyroid volumes of 75 healthy children (32F, 43M) with an age range of 2.0 to 11.8 yrs (median 7.6) ranged between 1.6 and 13.2 ml (median 4.8) and did not show a significant difference from the IDDM group from age 4 to 12. TA were positive in 18.8% of the IDDM group. Thyroid volume was higher in TA (+) diabetics (p = 0.05), a finding which may be attributed to a higher percentage of cases with elevated TSH in the TA (+) group. Two diabetic patients showed non-homogeneous hypoechogenicity in the ultrasound compatible with AIT which was later confirmed in one of these cases by aspiration biopsy. Ultrasound imaging of the thyroid may contribute to the evaluation of patients with AIT in IDDM.

Estimation of annual height velocity based on short- versus long-term measurements.

We assessed the relationships between annual height velocity, calculated from two measurements taken at intervals of 6, 12 and 24 months, in 69 healthy prepubertal children (34 male, 35 female) aged 6.5 years (range 6.25-6.75 yrs) who were followed for 2.5 years and measured biannually. Initial height values for age were within normal ranges except for one child with a height SDS of -2.0. Mean annual velocities also conformed to British norms. Significant differences were observed between consecutive six-monthly velocities and these values failed to predict annual velocities calculated from measurements taken at 12- or 24-month intervals. Seasonal effects were thought to have some impact on the six-monthly velocity differences. Height velocity, based on measurements taken at intervals of 12 months, was essentially similar to two-year velocity values. The results indicate that in estimating annual height velocity, six-month intervals between measurements may be misleading while 12-monthly measurements are as reliable as height velocity values based on measurements taken at two-year intervals.