Tumor risks and genotype-phenotype-proteotype analysis in 358 patients with germline mutations in SDHB and SDHD

Succinate dehydrogenase B (SDHB) and D (SDHD) subunit gene mutations predispose to adrenal and extraadrenal pheochromocytomas, head and neck paragangliomas (HNPGL), and other tumor types. We report tumor risks in 358 patients with SDHB (n=295) and SDHD (n=63) mutations. Risks of HNPGL and pheochromocytoma in SDHB mutation carriers were 29% and 52%, respectively, at age 60 years and 71% and 29%, respectively, in SDHD mutation carriers. Risks of malignant pheochromocytoma and renal tumors (14% at age 70 years) were higher in SDHB mutation carriers; 55 different mutations (including a novel recurrent exon 1 deletion) were identified. No clear genotype-phenotype correlations were detected for SDHB mutations. However, SDHD mutations predicted to result in loss of expression or a truncated or unstable protein were associated with a significantly increased risk of pheochromocytoma compared to missense mutations that were not predicted to impair protein stability (most such cases had the common p.Pro81Leu mutation). Analysis of the largest cohort of SDHB/D mutation carriers has enhanced estimates of penetrance and tumor risk and supports in silicon protein structure prediction analysis for functional assessment of mutations. The differing effect of the SDHD p.Pro81Leu on HNPGL and pheochromocytoma risks suggests differing mechanisms of tumorigenesis in SDH-associated HNPGL and pheochromocytoma.

Germline E-cadherin gene (CDH1) mutations predispose to familial gastric cancer and colorectal cancer

Inherited mutations in the E-cadherin gene ( CDH1 ) were described recently in three Maori kindreds with familial gastric cancer. Familial gastric cancer is genetically heterogeneous and it is not clear what proportion of gastric cancer susceptibility in non-Maori populations is due to germline CDH1 mutations. Therefore, we screened eight familial gastric cancer kindreds of British and Irish origin for germline CDH1 mutations, by SSCP analysis of all 16 exons and flanking sequences. Each family contained: (i) two cases of gastric cancer in first degree relatives with one affected before age 50 years; or (ii) three or more cases of gastric cancer. Novel germline CDH1 mutations (a nonsense and a splice site) were detected in two families (25%). Both mutations were predicted to truncate the E-cadherin protein in the signal peptide domain. In one family there was evidence of non-penetrance and susceptibility to both gastric and colorectal cancer; thus, in addition to six cases of gastric cancer, a CDH1 mutation carrier developed colorectal cancer at age 30 years. We have confirmed that germline mutations in the CDH1 gene cause familial gastric cancer in non-Maori populations. However, only a minority of familial gastric cancers can be accounted for by CDH1 mutations. Loss of E-cadherin function has been implicated in the pathogenesis of sporadic colorectal and other cancers, and our findings provide evidence that germline CDH1 mutations predispose to early onset colorectal cancer. Thus, CDH1 should be investigated as a cause of inherited susceptibility to both gastric and colorectal cancers.

TAC3/TACR3 mutations reveal preferential activation of gonadotropin-releasing hormone release by neurokinin B in neonatal life followed by reversal in adulthood

CONTEXT

Mutations in TAC3 and TACR3 (encoding neurokinin B and its receptor) have been identified in Turkish patients with idiopathic hypogonadotropic hypogonadism (IHH), but broader populations have not yet been tested and genotype-phenotype correlations have not been established.

OBJECTIVE

A broad cohort of normosmic IHH probands was screened for mutations in TAC3/TACR3 to evaluate the prevalence of such mutations and define the genotype/phenotype relationships.

DESIGN AND SETTING

The study consisted of sequencing of TAC3/TACR3, in vitro functional assays, and neuroendocrine phenotyping conducted in tertiary care centers worldwide.

PATIENTS OR OTHER PARTICIPANTS

345 probands, 18 family members, and 292 controls were studied.

INTERVENTION

Reproductive phenotypes throughout reproductive life and before and after therapy were examined.

MAIN OUTCOME MEASURE

Rare sequence variants in TAC3/TACR3 were detected.

RESULTS

In TACR3, 19 probands harbored 13 distinct coding sequence rare nucleotide variants [three nonsense mutations, six nonsynonymous, four synonymous (one predicted to affect splicing)]. In TAC3, one homozygous single base pair deletion was identified, resulting in complete loss of the neurokinin B decapeptide. Phenotypic information was available on 16 males and seven females with coding sequence variants in TACR3/TAC3. Of the 16 males, 15 had microphallus; none of the females had spontaneous thelarche. Seven of the 16 males and five of the seven females were assessed after discontinuation of therapy; six of the seven males and four of the five females demonstrated evidence for reversibility of their hypogonadotropism.

CONCLUSIONS

Mutations in the neurokinin B pathway are relatively common as causes of hypogonadism. Although the neurokinin B pathway appears essential during early sexual development, its importance in sustaining the integrity of the hypothalamic-pituitary-gonadal axis appears attenuated over time.

Sotos syndrome: a study of the diagnostic criteria and natural history

Seventy-nine patients with a provisional diagnosis of Sotos syndrome were clinically assessed, and their photographs between the ages of 1 and 6 years evaluated. These photographs, together with photographs of first degree relatives, also at ages 1 to 6 years, were reviewed by four clinical geneticists. Forty-one probands (but no first degree relatives) were identified in whom the facial gestalt was thought to be characteristic of Sotos syndrome. Comparison of anthropometric measurements, bone age, and developmental delay in these 41 probands showed marked differences between them and the remaining 38 probands, and allowed the formulation of guidelines for the diagnosis of Sotos syndrome. Length was identified as the most significantly increased prenatal parameter. In childhood occipitofrontal head circumference (OFC), height, and weight were all increased. OFC remained above the 97th centile in all but one case throughout childhood and adulthood, whereas height and weight had a tendency to return towards the mean. This 'normalisation' was more pronounced in females and was probably related to their early puberty. Early developmental delay and an advanced bone age, seen in 100% and 84% respectively of study cases, may be invariable in Sotos syndrome, but selection bias and limited data prevented confirmation of this supposition. The authors suggest that facial gestalt, growth pattern, bone age, and developmental delay are the major diagnostic criteria. Using these criteria, no affected first degree relatives were identified. There were few long term medical complications in the probands, but behavioural difficulties caused considerable parental concern.

The neuroimaging findings in Sotos syndrome

We reviewed the neuroimaging studies of 40 patients with classic Sotos syndrome. The studies consisted of CT scans only in 4 patients and one or more MRI scans in 36 patients. The diagnosis of Sotos syndrome was made using well-established clinical criteria. The neuroimaging studies of each patient were evaluated subjectively by visual inspection and the chief findings were tabulated and grouped into five categories: 1) ventricular abnormalities, 2) extracerebral fluid spaces, 3) midline abnormalities, 4) migrational abnormalities, and 5) others. The most common abnormality of the cerebral ventricles was prominence of the trigone (90%), followed by prominence of the occipital horns (75%) and ventriculomegaly (63%). The supratentorial extracerebral fluid spaces were increased for age in 70% of the patients and the fluid spaces in the posterior fossa were increased in 70% also. A variety of midline abnormalities were noted but anomalies of the corpus callosum were almost universal. Gray matter heterotopias occurred in only 3 (8%) of 36 patients. Periventricular leukomalacia, presumably the result of prenatal or perinatal difficulties and unrelated to the basic condition, was the most common of the miscellaneous other abnormalities noted. The neuroimaging findings of Sotos syndrome are distinct enough to allow differentiation of this syndrome from other mental retardation syndromes with macrocephaly.

A comprehensive next generation sequencing-based genetic testing strategy to improve diagnosis of inherited pheochromocytoma and paraganglioma

CONTEXT

Pheochromocytomas and paragangliomas are notable for a high frequency of inherited cases, many of which present as apparently sporadic tumors.

OBJECTIVE

The objective of this study was to establish a comprehensive next generation sequencing (NGS)-based strategy for the diagnosis of patients with pheochromocytoma and paraganglioma by testing simultaneously for mutations in MAX, RET, SDHA, SDHB, SDHC, SDHD, SDHAF2, TMEM127, and VHL.

DESIGN

After the methodology for the assay was designed and established, it was validated on DNA samples with known genotype and then patients were studied prospectively.

SETTING

The study was performed in a diagnostic genetics laboratory.

PATIENTS

DNA samples from 205 individuals affected with adrenal or extraadrenal pheochromocytoma/head and neck paraganglioma (PPGL/HNPGL) were analyzed. A proof-of-principle study was performed using 85 samples known to contain a variant in 1 or more of the genes to be tested, followed by prospective analysis of an additional 120 samples.

MAIN OUTCOME MEASURES

We assessed the ability to use an NGS-based method to perform comprehensive analysis of genes implicated in inherited PPGL/HNPGL.

RESULTS

The proof-of-principle study showed that the NGS assay and analysis gave a sensitivity of 98.7%. A pathogenic mutation was identified in 16.6% of the prospective analysis cohort of 120 patients.

CONCLUSIONS

A comprehensive NGS-based strategy for the analysis of genes associated with predisposition to PPGL and HNPGL was established, validated, and introduced into diagnostic service. The new assay provides simultaneous analysis of 9 genes and allows more rapid and cost-effective mutation detection than the previously used conventional Sanger sequencing-based methodology.

Genotype-phenotype analysis in congenital adrenal hyperplasia due to P450 oxidoreductase deficiency

CONTEXT

P450 oxidoreductase deficiency (PORD) is a unique congenital adrenal hyperplasia variant that manifests with glucocorticoid deficiency, disordered sex development (DSD), and skeletal malformations. No comprehensive data on genotype-phenotype correlations in Caucasian patients are available.

OBJECTIVE

The objective of the study was to establish genotype-phenotype correlations in a large PORD cohort.

DESIGN

The design of the study was the clinical, biochemical, and genetic assessment including multiplex ligation-dependent probe amplification (MLPA) in 30 PORD patients from 11 countries.

RESULTS

We identified 23 P450 oxidoreductase (POR) mutations (14 novel) including an exonic deletion and a partial duplication detected by MLPA. Only 22% of unrelated patients carried homozygous POR mutations. p.A287P was the most common mutation (43% of unrelated alleles); no other hot spot was identified. Urinary steroid profiling showed characteristic PORD metabolomes with variable impairment of 17α-hydroxylase and 21-hydroxylase. Short cosyntropin testing revealed adrenal insufficiency in 89%. DSD was present in 15 of 18 46,XX and seven of 12 46,XY individuals. Homozygosity for p.A287P was invariably associated with 46,XX DSD but normal genitalia in 46,XY individuals. The majority of patients with mild to moderate skeletal malformations, assessed by a novel scoring system, were compound heterozygous for missense mutations, whereas nearly all patients with severe malformations carried a major loss-of-function defect on one of the affected alleles.

CONCLUSIONS

We report clinical, biochemical, and genetic findings in a large PORD cohort and show that MLPA is a useful addition to POR mutation analysis. Homozygosity for the most frequent mutation in Caucasians, p.A287P, allows for prediction of genital phenotype and moderate malformations. Adrenal insufficiency is frequent, easily overlooked, but readily detected by cosyntropin testing.

PMS2 Mutations in Childhood Cancer

Until recently, the PMS2 DNA mismatch repair gene has only rarely been implicated as a cancer susceptibility locus. New studies have shown, however, that earlier analyses of this gene have had technical limitations and also that the genetic behavior of mutant PMS2 alleles is unusual, in that, unlike MLH1 or MSH2 mutations, PMS2 mutations show low heterozygote penetrance. As a result, a dominantly inherited cancer predisposition has not been a feature reported in families with PMS2 mutations. Such families have instead been ascertained through childhood-onset cancers in homozygotes or through apparently sporadic colorectal cancer in heterozygotes. We present further information on the phenotype associated with homozygous PMS2 deficiency in 13 patients from six families of Pakistani origin living in the United Kingdom. This syndrome is characterized by café-au-lait skin pigmentation and a characteristic tumor spectrum, including leukemias, lymphomas, cerebral malignancies (such as supratentorial primitive neuroectodermal tumors, astrocytomas, and glioblastomas), and colorectal neoplasia with an onset in early adult life. We present evidence for a founder effect in five families, all of which carried the same R802-->X mutation (i.e., arginine-802 to stop) in PMS2. This cancer syndrome can be mistaken for neurofibromatosis type 1, with important management implications including the risk of the disorder occurring in siblings and the likelihood of tumor development in affected individuals.

Risk of malignancy in Sotos syndrome

A questionnaire survey identified a possibly increased risk of malignancy for patients with Sotos syndrome. Because the sites and types of neoplasm found in these patients vary, no routine screening except for periodic clinical evaluation seems feasible.

Sotos syndrome

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Functional consequences of seven novel mutations in the CYP11B1 gene: four mutations associated with nonclassic and three mutations causing classic 11{beta}-hydroxylase deficiency

CONTEXT

Steroid 11beta-hydroxylase (CYP11B1) deficiency (11OHD) is the second most common form of congenital adrenal hyperplasia (CAH). Cases of nonclassic 11OHD are rare compared with the incidence of nonclassic 21-hydroxylase deficiency.

OBJECTIVE

The aim of the study was to analyze the functional consequences of seven novel CYP11B1 mutations (p.M88I, p.W116G, p.P159L, p.A165D, p.K254_A259del, p.R366C, p.T401A) found in three patients with classic 11OHD, two patients with nonclassic 11OHD, and three heterozygous carriers for CYP11B1 mutations.

METHODS

We conducted functional studies employing a COS7 cell in vitro expression system comparing wild-type (WT) and mutant CYP11B1 activity. Mutants were examined in a computational three-dimensional model of the CYP11B1 protein.

RESULTS

All mutations (p.W116G, p.A165D, p.K254_A259del) found in patients with classic 11OHD have absent or very little 11beta-hydroxylase activity relative to WT. The mutations detected in patients with nonclassic 11OHD showed partial functional impairment, with one patient being homozygous (p.P159L; 25% of WT) and the other patient compound heterozygous for a novel mild p.M88I (40% of WT) and the known severe p.R383Q mutation. The two mutations detected in heterozygous carriers (p.R366C, p.T401A) also reduced CYP11B1 activity by 23 to 37%, respectively.

CONCLUSION

Functional analysis results allow for the classification of novel CYP11B1 mutations as causative for classic and nonclassic 11OHD, respectively. Four partially inactivating mutations are predicted to result in nonclassic 11OHD. These findings double the number of mild CYP11B1 mutations previously described as associated with mild 11OHD. Our data are important to predict phenotypic expression and provide important information for clinical and genetic counseling in 11OHD.

KLB, encoding β-Klotho, is mutated in patients with congenital hypogonadotropic hypogonadism

Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic form of isolated gonadotropin‐releasing hormone (GnRH) deficiency caused by mutations in > 30 genes. Fibroblast growth factor receptor 1 (FGFR1) is the most frequently mutated gene in CHH and is implicated in GnRH neuron development and maintenance. We note that a CHH FGFR1 mutation (p.L342S) decreases signaling of the metabolic regulator FGF21 by impairing the association of FGFR1 with β‐Klotho (KLB), the obligate co‐receptor for FGF21. We thus hypothesized that the metabolic FGF21/KLB/FGFR1 pathway is involved in CHH. Genetic screening of 334 CHH patients identified seven heterozygous loss‐of‐function KLB mutations in 13 patients (4%). Most patients with KLB mutations (9/13) exhibited metabolic defects. In mice, lack of Klb led to delayed puberty, altered estrous cyclicity, and subfertility due to a hypothalamic defect associated with inability of GnRH neurons to release GnRH in response to FGF21. Peripheral FGF21 administration could indeed reach GnRH neurons through circumventricular organs in the hypothalamus. We conclude that FGF21/KLB/FGFR1 signaling plays an essential role in GnRH biology, potentially linking metabolism with reproduction.

Evaluation of SDHB, SDHD and VHL gene susceptibility testing in the assessment of individuals with non-syndromic phaeochromocytoma, paraganglioma and head and neck paraganglioma

OBJECTIVES

Research studies have reported that about a third of individuals with phaeochromocytoma/paraganglioma (PPGL) have an inherited predisposition, although the frequency of specific mutations can vary between populations. We evaluated VHL, SDHB and SDHD mutation testing in cohorts of patients with non-syndromic PPGL and head and neck paraganglioma (HNPGL).

DESIGN

Prospective, observational evaluation of NHS practice.

PATIENTS

Individuals with PPGL/HNPGL referred to a supraregional genetics testing service over a 10-year period.

MEASUREMENTS

Clinical (age, tumour site, malignancy, etc.), mutation frequencies and characteristics.

RESULTS

A total of 501 probands with PPGL (n = 413) or HNPGL (n = 88) were studied. Thirty-one percent of patients with PPGL presented had a pathogenic mutation in SDHB, SDHD or VHL. Mutation detection rates were highest in those with a positive family history (62%), malignancy (53%), multiple tumours (33%) or PGL (44%). Twenty-eight percent of individuals with a single sporadic phaeochromocytoma had a mutation. Overall, 63% of patients with HNPGL had a mutation (92% of those with a family history, 89% of those with multicentric tumours and 34% of those with a single sporadic HNPGL). Penetrance was calculated in 121 SDHB mutation-positive probands and 187 of their mutation-positive relatives. Most relatives were asymptomatic and lifetime penetrance in non-proband SDHB mutation carriers was <50%.

CONCLUSIONS

Practice-based evaluations of genetic testing in PPGL reveal high mutation detection rates. Although clinical criteria can be used to prioritize mutation testing, mutations were detected in 'low risk groups' indicating a need for comprehensive and inexpensive genetic testing strategies for PPGL and HNPGL.

Sotos syndrome: evolution of facial phenotype subjective and objective assessment

Sotos syndrome is characterised by pre- and post-natal growth acceleration, advanced bone age, developmental delay and a typical facial Gestalt. We have evaluated 45 individuals with Sotos syndrome who were between age 1 and 25 years, in order to better define the change in facial appearance over time. In each individual, a thorough assessment was made, serial photographs were reviewed, and a series of anthropometric craniofacial measurements was obtained. These were compared with age- and sex-matched normal standards. Both clinical and anthropometric evaluations show that the facial appearance which most clinical geneticists would regard as "classical" is established early in life. The head is large and dolichocephalic, with a rounded and prominent forehead, accentuated by frontoparietal balding. There is narrowing at the temples, fullness of the cheeks, and tapering to a pointed chin. With time, the normal process of facial change occurs, superimposed on that typical Gestalt. As the face lengthens, the dominance of the forehead diminishes and the chin achieves greater prominence. The mandible is long and narrow inferiorly, square or pointed, but prognathism is rare. In a small proportion of patients, a rounder face early in life may challenge diagnosis, but follow-up of these large newborn and older infants should allow diagnosis by early childhood. Visualisation of pattern profiles at different ages, supplemented by statistical measures of variability and similarity, support the clinical impressions outlined above.

Growth in Sotos syndrome

Although there are several reports on infant and childhood growth in patients with Sotos syndrome, there is little information on the final height achieved and puberty. Growth data on 40 patients (20 female and 20 male) aged 2-31 years were collected. These showed that patients with Sotos syndrome are excessively tall at birth, during infancy, and during childhood. Disproportionately long limbs constitute much of the increase in stature. However, the combination of advanced bone age and early onset of menarche led to a mean (SD) final height of 172.9 (5.7) cm in women. This is within the normal range for the population. Most of the men also attained a final height (mean, 184.3 cm; SD, 6.0) within the normal range, although exceptions were more likely in men than in women. Therefore, these results show that most patients with Sotos syndrome do not require intervention to limit their adult height.

Weaver syndrome

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Psychological characteristics of Sotos syndrome

A preliminary investigation of the psychological characteristics of 16 children aged between five and 15 years who met the strict diagnostic criteria for Sotos syndrome demonstrated that, while cognitive abilities vary, there are behavioural patterns that are characteristic of the disorder. The children were reported to have high rates of behavioural disturbance at home, particularly tantrums, destructiveness, social withdrawal, and eating and sleeping difficulties. The children were reported to present fewer problems in the school environment. Other difficulties expressed by parents are also described and quantified.

Autosomal dominant macrocephaly: benign familial macrocephaly or a new syndrome?

During the course of a clinical study of Sotos syndrome, six out of 79 probands failed to fit the phenotype of Sotos syndrome but showed remarkable similarities to each other and to a further 11 first- and second-degree relatives. Clinical features in these index cases included macrocephaly, greater than +3.5 SD; normal or near normal birth weight and length with subsequent relative obesity; variable developmental delay; and typical face, characterised by a square outline with frontal bossing, a "dished-out" mid-face, biparietal narrowing, and long philtrum. All recorded bone ages were less than the 75th centile, and two were below the 10th centile. The authors believe the original diagnosis was incorrect and that these cases likely represent a previously undescribed autosomal dominant macrocephaly syndrome.

Small cell lung carcinoma in a patient with Sotos syndrome: are genes at 3p21 involved in both conditions?

A 22 year old female with Sotos syndrome and a small cell lung carcinoma is described. This case is of interest not only because of the somatic growth pattern, atypical of Sotos syndrome, but also because of the association with a rare tumour. Of significance is the possible role of mutations at 3p21 in the aetiology of Sotos syndrome and tumour development.

Language and behavior in children with Sotos syndrome

OBJECTIVE

To examine language and behavior in children with Sotos syndrome, an overgrowth syndrome involving advanced bone age, characteristic facies, and developmental disability.

METHOD

Twenty-seven children with Sotos syndrome were compared with 20 children with overgrowth, intellectual disability, and facies not characteristic of Sotos syndrome. Ages ranged from 5 to 16 years. Direct assessment was undertaken with standardized measures of intelligence and language abilities. Behavior was examined by parent and teacher report.

RESULTS

Children with Sotos syndrome had levels of intelligence in the severely disabled to average range, with the majority falling in the borderline range. Mean level of intelligence was significantly higher than that observed for children in the comparison group. Language abilities were developed to a level consistent with overall level of intelligence. Rates of parent- and teacher-reported behavior problems were significantly higher than normal, but, with the exception of temper tantrums, did not differ from those observed in children in the comparison group. Attention-deficit hyperactivity disorder was observed in 38% of children with Sotos syndrome. They were more irritable and had more stereotypic behavior and inappropriate speech than is expected in children with intellectual disabilities, and they were more withdrawn and had more stereotypic behavior than children in the comparison group.

CONCLUSIONS

Assessment of language abilities revealed no specific language impairment. High rates of behavior problems were observed, but these were not higher than those observed for other large, delayed, dysmorphic children.

Hypothalamic Reproductive Endocrine Pulse Generator Activity Independent of Neurokinin B and Dynorphin Signaling

CONTEXT

Kisspeptin-neurokinin B (NKB)-dynorphin neurons are critical regulators of the hypothalamic-pituitary-gonadal axis. NKB and dynorphin are hypothesized to influence the frequency of GnRH pulses, whereas kisspeptin is hypothesized to be a generator of the GnRH pulse. How these neuropeptides interact remains unclear.

OBJECTIVE

To probe the role of NKB in GnRH pulse generation and to determine the interactions between NKB, kisspeptin, and dynorphin in humans and mice with a complete absence of NKB.

DESIGN

Case/control.

SETTING

Academic medical center.

PARTICIPANTS

Members of a consanguineous family bearing biallelic loss-of-function mutations in the gene encoding NKB and NKB-deficient mice.

INTERVENTIONS

Frequent blood sampling to characterize neuroendocrine profile and administration of kisspeptin, GnRH, and naloxone, a nonspecific opioid receptor antagonist used to block dynorphin.

MAIN OUTCOME MEASURES

LH pulse characteristics.

RESULTS

Humans lacking NKB demonstrate slow LH pulse frequency, which can be increased by opioid antagonism. Mice lacking NKB also demonstrate impaired LH secretion, which can be augmented with an identical pharmacologic manipulation. Both mice and humans with NKB deficiency respond to exogenous kisspeptin.

CONCLUSION

The preservation of LH pulses in the absence of NKB and dynorphin signaling suggests that both peptides are dispensable for GnRH pulse generation and kisspeptin responsiveness. However, NKB and dynorphin appear to have opposing roles in the modulation of GnRH pulse frequency.

Aging, meaning, and well-being: musings of a cultural historian

The social integration and well-being of old people depends in part on a culturally viable ideal of old age. Growing out of widely shared images and social values, an ideal old age legitimates norms and roles appropriate to the last stage of life. This article discusses the "late Calvinist" and "civilized" models of old age that flourished in Protestant, middle-class America between 1800 and 1920. It argues that the growing cultural dominance of science and the accelerating pace of capitalist productivity undercut the essential vision underlying these models: the view of life as a spiritual journey. The result has been a serious weakening of social meaning in aging and old age.

Marshall-Smith syndrome: the expanding phenotype

We report a child of 3 years 9 months with the Marshall-Smith syndrome (MSS), characterised by the typical facial features, developmental delay, and advanced bone age. After the diagnosis was made at 5 months of age, careful observation for respiratory complications and failure to thrive was initiated. By 3 1/2 years of age, although our patient had no life threatening respiratory complications, investigation showed significant upper airway obstruction, which has been successfully treated. Aggressive treatment for failure to thrive has also allowed her to maintain a weight on the 50th centile. The purpose of this report is to suggest that early diagnosis and aggressive management may improve the ultimate prognosis with respect to the respiratory and feeding difficulties seen in this rare syndrome.